Materials
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Questions and Answers

What is a primary advantage of using composite materials in aircraft construction?

  • High maintenance requirements
  • High thermal conductivity
  • Low corrosion resistance
  • High strength-to-weight ratio (correct)

    • What is a characteristic of ceramic materials used in aircraft applications?

  • Low strength-to-weight ratio
  • High thermal conductivity
  • Low corrosion resistance
  • High thermal resistance (correct)

    • Which steel alloy is commonly used in aircraft landing gear and engine components?

  • 6061-T6
  • 7075-T6
  • 4130 (correct)
  • 2024-T3

    • Which aluminum alloy is commonly used in aircraft skin and fuselage?

    <p>6061-T6</p> Signup and view all the answers

    What is a potential application of nanomaterials in aircraft construction?

    <p>High-temperature resistant coatings</p> Signup and view all the answers

    What is a consideration when welding aircraft materials?

    <p>Weld joint design</p> Signup and view all the answers

    Which type of material has structures or components on the nanoscale (typically 1-100 nm)?

    <p>Nanomaterials</p> Signup and view all the answers

    What is an advantage of using ceramic materials in aircraft applications?

    <p>Corrosion resistance</p> Signup and view all the answers

    Which aluminum alloy is commonly used in aircraft landing gear and engine components?

    <p>7075-T6</p> Signup and view all the answers

    What is a characteristic of composite materials used in aircraft structures?

    <p>Low maintenance requirements</p> Signup and view all the answers

    Which heat treatment process involves quenching steel in a molten salt bath or oil to achieve a specific microstructure?

    <p>Austempering</p> Signup and view all the answers

    What is the minimum percentage of chromium required in Martensitic Steel?

    <p>11.5%</p> Signup and view all the answers

    Which type of steel alloy contains chromium and molybdenum?

    <p>Chromoly</p> Signup and view all the answers

    What is the primary goal of the austempering heat treatment process?

    <p>To achieve a combination of high strength, toughness, and resistance to corrosion and fatigue</p> Signup and view all the answers

    Which type of steel alloy is often used in critical aircraft structures such as engine mounts and wing components?

    <p>High-strength Alloy</p> Signup and view all the answers

    What is the purpose of the tempering heat treatment process?

    <p>To reduce the hardness of steel and increase its toughness</p> Signup and view all the answers

    Which heat treatment process involves heating steel in a nitrogen atmosphere to achieve high surface hardness and wear resistance?

    <p>Nitriding</p> Signup and view all the answers

    What is a characteristic of Chromoly steel?

    <p>High strength and toughness</p> Signup and view all the answers

    Which heat treatment process involves heating steel to a critical temperature, then slowly cooling it to relieve internal stresses and achieve a specific microstructure?

    <p>Annealing</p> Signup and view all the answers

    What is a common application of Martensitic Steel?

    <p>Aircraft landing gear and engine mounts</p> Signup and view all the answers

    What is the name of the iron alloy that contains 2.1 to 4.3% carbon?

    <p>Carbon Steel</p> Signup and view all the answers

    Which microstructure is a combination of Ferrite and Cementite?

    <p>Pearlite</p> Signup and view all the answers

    What is the term for steels that contain Ferrite as the primary microstructure?

    <p>Ferritic</p> Signup and view all the answers

    What is the name of the microstructure that is formed when steel is rapidly cooled?

    <p>Martensite</p> Signup and view all the answers

    What is the term for steels that contain Austenite as the primary microstructure?

    <p>Austenitic</p> Signup and view all the answers

    Which alloy group has excellent corrosion resistance and high thermal and electrical conductivity?

    <p>1000 series</p> Signup and view all the answers

    What is the principal alloying element in the 2000 series alloy group?

    <p>Copper</p> Signup and view all the answers

    Which alloy group has moderate strength and good working characteristics?

    <p>3003</p> Signup and view all the answers

    What is indicated by the second digit in the alloy designation in the 2xxx through 8xxx alloy groups?

    <p>Alloy modifications</p> Signup and view all the answers

    Which element is a major impurity in the 1000 series alloy group?

    <p>Iron</p> Signup and view all the answers

    Which alloy group has optimum properties equal to mild steel after solution heat treatment?

    <p>2000 series</p> Signup and view all the answers

    Which alloy series is known for its good welding and corrosion resistant characteristics?

    <p>5000 series</p> Signup and view all the answers

    What is the primary alloying element in the 4000 series of aluminum alloys?

    <p>Silicon</p> Signup and view all the answers

    Which alloy series is heat-treatable and has corrosion resistant characteristics?

    <p>6000 series</p> Signup and view all the answers

    What is the principal alloying element in the 7000 series of aluminum alloys?

    <p>Zinc</p> Signup and view all the answers

    Which alloy is known for its very high strength and corrosion resistant characteristics?

    <p>7075</p> Signup and view all the answers

    What is the result of coupling zinc with magnesium in the 7000 series alloys?

    <p>Heat-treatable alloys of very high strength</p> Signup and view all the answers

    Which alloy series has a limited response to heat treatment when used in welding heat-treatable alloys?

    <p>4000 series</p> Signup and view all the answers

    What is the composition of the 6061 alloy?

    <p>0.25% Cu, 0.6% Si, 1.3% Mg, 0.25% Zn</p> Signup and view all the answers

    Which alloy has exceptional high strength, toughness, and corrosion resistance?

    <p>Manganese bronze</p> Signup and view all the answers

    What is the primary advantage of using cast aluminum bronze in bearings and pump parts?

    <p>High corrosion resistance</p> Signup and view all the answers

    Which alloy contains about 95 percent copper, 3 percent silicon, and 2 percent manganese, zinc, iron, tin, and aluminum?

    <p>Silicon bronze</p> Signup and view all the answers

    What is the approximate percentage of nickel in Monel?

    <p>68 percent</p> Signup and view all the answers

    Which property makes aluminum bronzes suitable for diaphragms, gears, and pumps?

    <p>Great strength, hardness, and resistance to both shock and fatigue</p> Signup and view all the answers

    What is the primary advantage of using cast aluminum bronze in areas exposed to salt water and corrosive gases?

    <p>Excellent resistance to corrosion, shock, and fatigue</p> Signup and view all the answers

    Which alloy can be formed, extruded, drawn, or rolled to any desired shape?

    <p>Manganese bronze</p> Signup and view all the answers

    What is the primary application of manganese bronze in rod form?

    <p>Machined parts for aircraft landing gears and brackets</p> Signup and view all the answers

    What is the carbon percentage range in medium carbon steel?

    <p>0.30 to 0.50 percent</p> Signup and view all the answers

    What type of steel is SAE 1035?

    <p>Medium carbon steel</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness?

    <p>Carbon</p> Signup and view all the answers

    What is the designation for Nickel-Chromium steel?

    <p>SAE 30xx</p> Signup and view all the answers

    What is the primary element added to steel to increase its corrosion resistance?

    <p>Chromium</p> Signup and view all the answers

    What is the designation for Manganese steel?

    <p>SAE 13xx</p> Signup and view all the answers

    What is the designation for Chromium-Molybdenum steel?

    <p>SAE 41xx</p> Signup and view all the answers

    What is the primary benefit of adding nickel to carbon steel?

    <p>Increased hardness and tensile strength</p> Signup and view all the answers

    What type of steel is commonly used for making flat springs and coil springs?

    <p>SAE 1095</p> Signup and view all the answers

    What is the primary characteristic of chromium steel?

    <p>High hardness and strength</p> Signup and view all the answers

    What is the primary advantage of using stainless steel in aircraft construction?

    <p>Increased strength and corrosion resistance</p> Signup and view all the answers

    What is the composition of 18-8 steel?

    <p>18% chromium, 8% nickel</p> Signup and view all the answers

    What is the primary use of SAE 2330 steel?

    <p>Aircraft parts such as bolts, terminals, keys, clevises, and pins</p> Signup and view all the answers

    What is the effect of cold working on 18-8 steel?

    <p>Increased strength</p> Signup and view all the answers

    What is the approximate percentage of nickel in Monel?

    <p>68</p> Signup and view all the answers

    What is the primary advantage of using K-Monel in aircraft?

    <p>Corrosion resistance and nonmagnetic properties</p> Signup and view all the answers

    What is the tensile strength of Monel when forged and annealed?

    <p>80,000 psi</p> Signup and view all the answers

    Which of the following is a characteristic of Nickel alloys?

    <p>High strength and corrosion resistance</p> Signup and view all the answers

    What is the primary application of Inconel alloys?

    <p>Exhaust systems that require high strength and corrosion resistance</p> Signup and view all the answers

    What is K-Monel used for in aircraft?

    <p>Gears and structural members</p> Signup and view all the answers

    What is the result of adding a small amount of aluminum to the Monel formula?

    <p>K-Monel</p> Signup and view all the answers

    What is the primary advantage of using chrome-molybdenum steel in aircraft construction?

    <p>High toughness and wear resistance</p> Signup and view all the answers

    What is the typical carbon content of chrome-molybdenum steel used in aircraft construction?

    <p>0.25 to 0.55 percent</p> Signup and view all the answers

    What is the purpose of adding molybdenum to chromium steel?

    <p>To raise the ultimate strength of steel without affecting ductility or workability</p> Signup and view all the answers

    What is the primary difference between Inconel and stainless steel?

    <p>Inconel has a higher nickel content</p> Signup and view all the answers

    What is the advantage of using SAE 6150 steel for making springs?

    <p>It has high toughness and resistance to wear and fatigue</p> Signup and view all the answers

    What is the typical application of chrome-vanadium steel with high carbon content?

    <p>Manufacturing ball and roller bearings</p> Signup and view all the answers

    What is the benefit of using chrome-molybdenum steel for welded structural parts and assemblies?

    <p>It is adaptable for welding and has high strength</p> Signup and view all the answers

    What is the primary reason why nickel Inconel alloys are used in turbine engines?

    <p>Their high corrosion resistance under extremely high-temperature conditions</p> Signup and view all the answers

    What is the purpose of applying a drop of cupric chloride and hydrochloric acid solution to a metal sample?

    <p>To identify the type of metal</p> Signup and view all the answers

    What is the most important consideration when selecting substitute metals for aircraft repair and maintenance?

    <p>Maintaining original strength</p> Signup and view all the answers

    What is the primary method of metalworking used for steel?

    <p>Hot working</p> Signup and view all the answers

    What is the result of the hot working process on an ingot?

    <p>The surface is solid, but the interior is still molten</p> Signup and view all the answers

    What is the purpose of the four requirements when selecting substitute metals?

    <p>To ensure the metal meets the original structural requirements</p> Signup and view all the answers

    What is the difference between the result of the cupric chloride and hydrochloric acid solution test on nickel Inconel and stainless steel?

    <p>Nickel Inconel turns shiny, while stainless steel turns copper-colored</p> Signup and view all the answers

    What is a characteristic of aluminum bronzes?

    <p>High degree of resistance to corrosion</p> Signup and view all the answers

    What percentage of aluminum is typically present in aluminum bronzes?

    <p>Up to 16 percent</p> Signup and view all the answers

    What is the primary application of cast aluminum bronze?

    <p>Bearings and pump parts</p> Signup and view all the answers

    What is the composition of Monel?

    <p>68 percent copper, 29 percent nickel, 0.2 percent iron, 1 percent manganese</p> Signup and view all the answers

    What is the primary advantage of using manganese bronze?

    <p>High strength and corrosion resistance</p> Signup and view all the answers

    What is the composition of silicon bronze?

    <p>95 percent copper, 3 percent silicon, 2 percent manganese, zinc, iron, tin, and aluminum</p> Signup and view all the answers

    What is the primary application of manganese bronze in rod form?

    <p>Machined parts for aircraft landing gears and brackets</p> Signup and view all the answers

    What is the primary advantage of using cast aluminum bronze in areas exposed to salt water and corrosive gases?

    <p>Good corrosion resistance and high strength</p> Signup and view all the answers

    What is the characteristic of silicon bronze?

    <p>High strength and great corrosion resistance</p> Signup and view all the answers

    What is the primary advantage of using aluminum bronzes?

    <p>Good corrosion resistance and high strength</p> Signup and view all the answers

    What is a characteristic of Chrome-Molybdenum steel?

    <p>It has high strength, toughness, and resistance to wear and fatigue.</p> Signup and view all the answers

    What is the advantage of using Chrome-Molybdenum steel in aircraft construction?

    <p>It has high strength and resistance to wear and fatigue.</p> Signup and view all the answers

    What is Inconel?

    <p>A nickel-chromium-iron alloy.</p> Signup and view all the answers

    What is the main characteristic of nickel steel?

    <p>High hardness, tensile strength, and elastic limit</p> Signup and view all the answers

    Why are identifying tests necessary for Inconel and stainless steel?

    <p>Because they have similar appearances.</p> Signup and view all the answers

    What is a characteristic of Chrome-Vanadium steel?

    <p>It has high carbon content.</p> Signup and view all the answers

    What is the primary use of SAE 1095 steel?

    <p>Making flat springs and coil springs</p> Signup and view all the answers

    What is the primary advantage of using Molybdenum in steel alloys?

    <p>It raises the ultimate strength of the steel without affecting ductility or workability.</p> Signup and view all the answers

    What is the main advantage of chromium steel?

    <p>High hardness, strength, and corrosion-resistant properties</p> Signup and view all the answers

    What is the main difference between Chrome-Molybdenum steel and carbon steel?

    <p>Chrome-Molybdenum steel has higher strength and resistance to wear and fatigue.</p> Signup and view all the answers

    What is the composition of 18-8 steel?

    <p>18% chromium, 8% nickel</p> Signup and view all the answers

    What is the main difference between stainless steel and mild steel?

    <p>Stainless steel expands more than mild steel</p> Signup and view all the answers

    What is the typical carbon percentage range in SAE 6150?

    <p>0.25 to 0.55%</p> Signup and view all the answers

    What is the primary application of chrome-vanadium steel?

    <p>Not mentioned in the content</p> Signup and view all the answers

    What is the main advantage of using stainless steel in aircraft construction?

    <p>Corrosion resistance and high thermal conductivity</p> Signup and view all the answers

    What is the effect of cold working on 18-8 steel?

    <p>It increases its strength</p> Signup and view all the answers

    What is the carbon percentage range in medium carbon steel?

    <p>0.30 to 0.50 percent</p> Signup and view all the answers

    What type of steel is SAE 1035?

    <p>Medium carbon steel</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness?

    <p>Carbon</p> Signup and view all the answers

    What series of steel contains Nickel 3.50% and Chromium 1.55%?

    <p>33xx</p> Signup and view all the answers

    What series of steel contains Molybdenum 0.20 or 0.25%?

    <p>40xx</p> Signup and view all the answers

    What series of steel contains Chromium 0.50, or 0.40 or 0.50%?

    <p>50xx</p> Signup and view all the answers

    What series of steel contains Nickel 0.30%, Chromium 0.40%, Molybdenum 0.12%?

    <p>81xx</p> Signup and view all the answers

    What series of steel contains Manganese 0.85%, Silicon 2.00%, Chromium 0 or 0.35%?

    <p>92xx</p> Signup and view all the answers

    What is the primary advantage of using chrome-molybdenum steel in aircraft construction?

    <p>It has high weldability and adaptability to high temperature service</p> Signup and view all the answers

    What is the percentage range of molybdenum in chrome-molybdenum steel used in aircraft construction?

    <p>0.15 to 0.25%</p> Signup and view all the answers

    Which of the following is a characteristic of chrome-molybdenum steel?

    <p>It is ductile and resistant to fatigue</p> Signup and view all the answers

    What is the primary application of Inconel in aircraft construction?

    <p>Exhaust systems and heat shields</p> Signup and view all the answers

    What is the method of identification used to distinguish between Inconel and stainless steel?

    <p>Electrochemical technique</p> Signup and view all the answers

    What is the primary advantage of using chrome-molybdenum steel over carbon steel in aircraft construction?

    <p>It is more weldable and adaptable to high temperature service</p> Signup and view all the answers

    What is the approximate carbon content range of SAE 6150 steel?

    <p>0.50 to 0.60%</p> Signup and view all the answers

    What is the primary alloying element in chrome-molybdenum steel?

    <p>Chromium</p> Signup and view all the answers

    What is the primary advantage of using chrome-nickel steel in aircraft construction?

    <p>It has high corrosion resistance</p> Signup and view all the answers

    What is the effect of nickel on the properties of carbon steel?

    <p>It increases the hardness, tensile strength, and elastic limit</p> Signup and view all the answers

    What is the approximate percentage of vanadium in chrome-vanadium steel?

    <p>1%</p> Signup and view all the answers

    Which type of steel is commonly used for making coil springs?

    <p>SAE 1095</p> Signup and view all the answers

    What is the primary alloy of stainless steel?

    <p>Chromium</p> Signup and view all the answers

    What is a common application of 18-8 steel in aircraft construction?

    <p>Fabrication of exhaust collectors</p> Signup and view all the answers

    What is the effect of cold working on 18-8 steel?

    <p>It increases its strength</p> Signup and view all the answers

    Which type of steel is high in hardness, strength, and corrosion-resistant properties?

    <p>Chromium steel</p> Signup and view all the answers

    What is the carbon percentage range in high carbon steel?

    <p>0.50 to 1.05 percent</p> Signup and view all the answers

    What is SAE 1035 steel used for?

    <p>Light forgings and rod ends</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness in 40xx series?

    <p>Molybdenum</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness in 50xx series?

    <p>Chromium</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness in 33xx series?

    <p>Nickel and chromium</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness in 46xx series?

    <p>Nickel and molybdenum</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness in 47xx series?

    <p>Nickel, chromium, and molybdenum</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness in 61xx series?

    <p>Vanadium</p> Signup and view all the answers

    What is the primary effect of adding nickel to carbon steel?

    <p>It increases the hardness and tensile strength</p> Signup and view all the answers

    What is the primary application of Chromium Steel?

    <p>Heat-treated forgings that require greater toughness and strength</p> Signup and view all the answers

    What is the corrosion-resistant degree of Chrome-nickel Steel determined by?

    <p>Surface condition of the metal, as well as composition, temperature, and concentration of the corrosive agent</p> Signup and view all the answers

    What is the principal alloy of Stainless Steel?

    <p>Chromium</p> Signup and view all the answers

    What is a distinctive feature of 18-8 Steel?

    <p>Cold working increases its strength</p> Signup and view all the answers

    What is the composition of Chrome-vanadium Steel?

    <p>Approximately 18 percent vanadium and 1 percent chromium</p> Signup and view all the answers

    What is a challenge when welding Stainless Steel?

    <p>It expands about 50 percent more than mild steel and conducts heat only about 40 percent as rapidly</p> Signup and view all the answers

    What can be used for almost any part of an aircraft?

    <p>Stainless Steel</p> Signup and view all the answers

    What is a characteristic of chrome-molybdenum steel when heat-treated?

    <p>It is deep hardening, easily machined, and readily welded</p> Signup and view all the answers

    What is the primary advantage of using chrome-molybdenum steel in aircraft construction?

    <p>It provides high strength, toughness, and resistance to wear and fatigue</p> Signup and view all the answers

    What is the purpose of adding molybdenum to chromium steel?

    <p>To raise its ultimate strength without affecting ductility or workability</p> Signup and view all the answers

    What is a characteristic of Inconel, a nickel-chromium-iron alloy?

    <p>It is closely resembling stainless steel in appearance</p> Signup and view all the answers

    What is the carbon percentage range in high carbon steel?

    <p>0.50 to 1.05 percent</p> Signup and view all the answers

    What is the carbon content range of the series of chrome-molybdenum steel commonly used in aircraft construction?

    <p>0.25 to 0.55 percent</p> Signup and view all the answers

    What type of steel alloy contains chromium and molybdenum?

    <p>47xx steel</p> Signup and view all the answers

    What is a use of SAE 6150 steel?

    <p>Making springs</p> Signup and view all the answers

    What is a benefit of using chrome-molybdenum steel in welded structural parts and assemblies?

    <p>It is especially adaptable for welding</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness?

    <p>Carbon</p> Signup and view all the answers

    What is a characteristic of heat-treated SAE X4130 tube?

    <p>It is approximately four times as strong as an SAE 1025 tube of the same weight and size</p> Signup and view all the answers

    What type of steel is especially adaptable for machining or forging and where surface hardness is desirable?

    <p>Medium carbon steel</p> Signup and view all the answers

    Which type of steel alloy contains nickel and chromium?

    <p>33xx steel</p> Signup and view all the answers

    What type of steel is SAE 1035?

    <p>Medium carbon steel</p> Signup and view all the answers

    Which series of steel alloys contains manganese?

    <p>13xx steel</p> Signup and view all the answers

    Which type of steel alloy contains nickel, chromium, and molybdenum?

    <p>43xx steel</p> Signup and view all the answers

    What is the carbon percentage range in high carbon steel?

    <p>0.50 to 1.05 percent</p> Signup and view all the answers

    Which type of steel contains chromium and molybdenum?

    <p>Chromium Steel</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness?

    <p>Carbon</p> Signup and view all the answers

    Which type of steel is SAE 1035?

    <p>Medium Carbon Steel</p> Signup and view all the answers

    What type of steel contains nickel and chromium?

    <p>Chrome-nickel Steel</p> Signup and view all the answers

    Which type of steel has a carbon percentage range of 0.30 to 0.50 percent?

    <p>Medium Carbon Steel</p> Signup and view all the answers

    What type of steel is commonly used in rod ends and light forgings?

    <p>SAE 1035 Steel</p> Signup and view all the answers

    Which type of steel alloy contains manganese?

    <p>13xx Steel</p> Signup and view all the answers

    What is the primary characteristic of the spark stream in low carbon steel?

    <p>Long, straight shafts with few white sprigs</p> Signup and view all the answers

    What is the carbon percentage range in low carbon steel?

    <p>0.10 to 0.30 percent</p> Signup and view all the answers

    What is the characteristic of the spark stream in nickel steel?

    <p>Small white blocks of light within the main burst</p> Signup and view all the answers

    What is the equivalent SAE number range for low carbon steel?

    <p>1010 to 1030</p> Signup and view all the answers

    What is the use of low carbon steel in sheet form?

    <p>Secondary structural parts and clamps</p> Signup and view all the answers

    What is the characteristic of the spark stream in wrought iron?

    <p>Long shafts that are straw colored as they leave the stone and white at the end</p> Signup and view all the answers

    What is the characteristic of the spark stream in cast iron?

    <p>Red sparks that turn to a straw color</p> Signup and view all the answers

    What happens to the spark stream as the carbon content of the steel increases?

    <p>The number of sprigs along each shaft increases</p> Signup and view all the answers

    What is the percentage of carbon content in steel beyond which there is no increase in wear resistance?

    <p>0.85 percent</p> Signup and view all the answers

    What is the temperature range in which carbon steel must be cooled to harden?

    <p>Below 1,000 °F in less than 1 second</p> Signup and view all the answers

    Why can't pure iron, wrought iron, and extremely low carbon steels be appreciably hardened by heat treatment?

    <p>They contain no hardening element</p> Signup and view all the answers

    What is the transformation that occurs when cast iron is cooled rapidly?

    <p>Formation of white iron</p> Signup and view all the answers

    What is the primary factor that influences the critical points of heat treatment in steel?

    <p>Composition of the steel</p> Signup and view all the answers

    What is the result of hardening treatment on the ductility of steel?

    <p>It decreases the ductility of steel</p> Signup and view all the answers

    What is the temperature range in which austenite begins to transform into fine pearlite?

    <p>Below 1,000 °F</p> Signup and view all the answers

    What is the purpose of rapid cooling in the hardening treatment of steel?

    <p>To increase the hardness and strength of steel</p> Signup and view all the answers

    What happens when cast iron is cooled rapidly?

    <p>Forms white iron, which is hard and brittle</p> Signup and view all the answers

    What is the maximum carbon content percentage beyond which there is no increase in wear resistance?

    <p>0.85%</p> Signup and view all the answers

    What is the temperature range below which carbon steel must be cooled in less than 1 second to achieve hardening?

    <p>900-1000°F</p> Signup and view all the answers

    What is the primary reason why pure iron, wrought iron, and extremely low carbon steels cannot be hardened by heat treatment?

    <p>They contain no hardening element</p> Signup and view all the answers

    What happens when the carbon content of steel is increased beyond 0.85%?

    <p>There is no increase in wear resistance</p> Signup and view all the answers

    What is the primary purpose of the heat treatment process in steel?

    <p>To increase the hardness and strength of steel</p> Signup and view all the answers

    What is the result of cooling steel rapidly during the hardening process?

    <p>The formation of very fine carbide particles</p> Signup and view all the answers

    What is the critical point in the heat treatment of steel?

    <p>The temperature at which the carbide particles are dissolved in austenite</p> Signup and view all the answers

    What is the carbon percentage range in medium carbon steel?

    <p>0.30 to 0.50 percent</p> Signup and view all the answers

    What type of steel is SAE 1035?

    <p>Medium carbon steel</p> Signup and view all the answers

    What is the primary element added to steel to increase its hardness?

    <p>Carbon</p> Signup and view all the answers

    Which type of steel alloy contains chromium and molybdenum?

    <p>41xx Chromium steel</p> Signup and view all the answers

    What is the purpose of the chromium addition in steel alloys?

    <p>To increase corrosion resistance</p> Signup and view all the answers

    Which type of steel alloy has excellent corrosion resistance and high thermal and electrical conductivity?

    <p>Nickel steel</p> Signup and view all the answers

    What is the primary advantage of using chrome-nickel steel in aircraft applications?

    <p>Excellent corrosion resistance</p> Signup and view all the answers

    Which type of steel alloy is often used in critical aircraft structures such as engine mounts and wing components?

    <p>Chrome-nickel steel</p> Signup and view all the answers

    What is the characteristic of the spark stream produced by nickel steel during spark testing?

    <p>It contains small white blocks of light within the main burst</p> Signup and view all the answers

    Which type of steel contains carbon in percentages ranging from 0.10 to 0.30 percent?

    <p>Low carbon steel</p> Signup and view all the answers

    What is the characteristic of the spark stream produced by wrought iron during spark testing?

    <p>It produces long shafts that are straw colored as they leave the stone</p> Signup and view all the answers

    What is the characteristic of the spark stream produced by cast iron during spark testing?

    <p>It produces long shafts that are red as they leave the stone</p> Signup and view all the answers

    What is the characteristic of the spark stream produced by low carbon steel during spark testing?

    <p>It produces long, straight shafts having a few white sprigs</p> Signup and view all the answers

    What is the use of low carbon steel in sheet form?

    <p>For secondary structural parts and clamps</p> Signup and view all the answers

    What is the use of low carbon steel in tubular form?

    <p>For moderately stressed structural parts</p> Signup and view all the answers

    What is the range of SAE numbers for low carbon steel?

    <p>1010 to 1030</p> Signup and view all the answers

    Study Notes

    Aircraft Materials

    Aluminum Alloys

    • Widely used in aircraft construction due to high strength-to-weight ratio, corrosion resistance, and low cost
    • Common alloys:
      • 2024-T3: high strength, used in aircraft structures
      • 6061-T6: moderate strength, used in aircraft skin and fuselage
      • 7075-T6: high strength, used in aircraft landing gear and engine components

    Steel Alloys

    • Used in high-stress applications due to high strength, high fatigue resistance, and low cost
    • Common alloys:
      • 4130: chromium-molybdenum alloy, used in aircraft landing gear and engine components
      • 15-5PH: precipitation-hardening alloy, used in aircraft fasteners and fittings
      • 17-4PH: precipitation-hardening alloy, used in aircraft engine components and fasteners

    Composite Materials

    • Made from a combination of materials, such as carbon fibers, glass fibers, and polymers
    • Advantages:
      • High strength-to-weight ratio
      • Corrosion resistance
      • Low maintenance
    • Used in aircraft structures, such as:
      • Wings
      • Fuselage
      • Control surfaces
      • Engine components

    Ceramic Materials

    • Used in high-temperature applications due to high thermal resistance and low thermal conductivity
    • Advantages:
      • High temperature resistance
      • Corrosion resistance
      • Low thermal conductivity
    • Used in aircraft components, such as:
      • Heat shields
      • Engine components
      • Thermal protection systems

    Nanomaterials

    • Materials with structures or components on the nanoscale (typically 1-100 nm)
    • Advantages:
      • High strength-to-weight ratio
      • High thermal resistance
      • Corrosion resistance
    • Potential applications in aircraft materials:
      • Lightweight structural components
      • High-temperature resistant coatings
      • Self-healing materials

    Aircraft Welding

    • Techniques used to join aircraft materials, including:
      • Gas tungsten arc welding (GTAW)
      • Gas metal arc welding (GMAW)
      • Resistance welding
      • Friction stir welding
    • Important considerations:
      • Material compatibility
      • Weld joint design
      • Welding process control
      • Post-weld heat treatment

    Aircraft Materials

    Aluminum Alloys

    • Used in aircraft construction due to high strength-to-weight ratio, corrosion resistance, and low cost
    • Common alloys:
      • 2024-T3: high strength for aircraft structures
      • 6061-T6: moderate strength for aircraft skin and fuselage
      • 7075-T6: high strength for aircraft landing gear and engine components

    Steel Alloys

    • Used in high-stress applications due to high strength, high fatigue resistance, and low cost
    • Common alloys:
      • 4130: chromium-molybdenum alloy for aircraft landing gear and engine components
      • 15-5PH: precipitation-hardening alloy for aircraft fasteners and fittings
      • 17-4PH: precipitation-hardening alloy for aircraft engine components and fasteners

    Composite Materials

    • Combine materials like carbon fibers, glass fibers, and polymers for:
      • High strength-to-weight ratio
      • Corrosion resistance
      • Low maintenance
    • Used in aircraft structures:
      • Wings
      • Fuselage
      • Control surfaces
      • Engine components

    Ceramic Materials

    • Used in high-temperature applications due to:
      • High thermal resistance
      • Low thermal conductivity
    • Advantages:
      • Corrosion resistance
      • High temperature resistance
    • Used in aircraft components:
      • Heat shields
      • Engine components
      • Thermal protection systems

    Nanomaterials

    • Materials with structures or components on the nanoscale (1-100 nm)
    • Advantages:
      • High strength-to-weight ratio
      • High thermal resistance
      • Corrosion resistance
    • Potential applications:
      • Lightweight structural components
      • High-temperature resistant coatings
      • Self-healing materials

    Aircraft Welding

    • Techniques for joining aircraft materials:
      • Gas tungsten arc welding (GTAW)
      • Gas metal arc welding (GMAW)
      • Resistance welding
      • Friction stir welding
    • Important considerations:
      • Material compatibility
      • Weld joint design
      • Welding process control
      • Post-weld heat treatment

    Austempering

    • Increases strength and toughness of steel through a heat treatment process
    • Involves heating steel to a critical temperature, then quenching it in a molten salt bath or oil
    • Achieves a specific microstructure, resulting in high strength, toughness, and resistance to corrosion and fatigue

    Martensitic Steel

    • High-strength steel alloy with a minimum of 11.5% chromium
    • Known for high hardness, strength, and resistance to corrosion and wear
    • Used in high-stress applications such as landing gear, engine mounts, and fasteners
    • Can be heat-treated to achieve high strength-to-weight ratios

    Chromoly

    • High-strength, low-alloy steel containing chromium and molybdenum
    • Known for high strength, toughness, and resistance to corrosion and fatigue
    • Used in aircraft landing gear, axles, and other high-stress components
    • Can be heat-treated to achieve high strength-to-weight ratios

    High-strength Alloy

    • Steel alloy containing chromium, molybdenum, and nickel
    • Known for high strength, toughness, and resistance to corrosion and fatigue
    • Used in critical aircraft structures such as engine mounts, fasteners, and wing components
    • Can be heat-treated to achieve high strength-to-weight ratios

    Heat Treatment Processes

    Annealing

    • Heats steel to a critical temperature, then slowly cools it to relieve internal stresses
    • Achieves a specific microstructure

    Hardening

    • Heats steel to a critical temperature, then quenches it in oil or water
    • Achieves high hardness and strength

    Tempering

    • Heats steel to a specific temperature to reduce its hardness
    • Increases toughness

    Nitriding

    • Heats steel in a nitrogen atmosphere to achieve high surface hardness and wear resistance

    Aircraft Materials

    • Aluminum alloys are widely used in aircraft construction due to their high strength-to-weight ratio, corrosion resistance, and low cost
      • Common alloys include 2024-T3, 6061-T6, and 7075-T6, each with unique properties and applications

    Steel Alloys

    • Steel alloys are used in high-stress applications due to their high strength, high fatigue resistance, and low cost
      • Common alloys include 4130, 15-5PH, and 17-4PH, each with unique properties and applications

    Composite Materials

    • Composite materials are made from a combination of materials, such as carbon fibers, glass fibers, and polymers
      • Advantages include high strength-to-weight ratio, corrosion resistance, and low maintenance
      • Used in aircraft structures, such as wings, fuselage, control surfaces, and engine components

    Ceramic Materials

    • Ceramic materials are used in high-temperature applications due to their high thermal resistance and low thermal conductivity
      • Advantages include high temperature resistance, corrosion resistance, and low thermal conductivity
      • Used in aircraft components, such as heat shields, engine components, and thermal protection systems

    Nanomaterials

    • Nanomaterials have structures or components on the nanoscale (typically 1-100 nm)
      • Advantages include high strength-to-weight ratio, high thermal resistance, and corrosion resistance
      • Potential applications include lightweight structural components, high-temperature resistant coatings, and self-healing materials

    Aircraft Welding

    • Aircraft welding techniques include gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), resistance welding, and friction stir welding
      • Important considerations include material compatibility, weld joint design, welding process control, and post-weld heat treatment

    Heat Treatment Processes

    • Austempering is a heat treatment process that increases strength and toughness in steel
    • Martensitic steel is a type of high-strength steel alloy that contains a minimum of 11.5% chromium
    • Chromoly is a type of high-strength, low-alloy steel that contains chromium and molybdenum
    • High-strength alloys contain a combination of elements such as chromium, molybdenum, and nickel
      • Each type of steel alloy has unique properties and applications
    • Heat treatment processes include annealing, hardening, tempering, austempering, and nitriding
      • Each process achieves a specific microstructure or property in steel alloys

    Alloying Elements and Composition

    • Aluminum alloys are classified into series based on their principal alloying element
    • 1000 series: 99% aluminum or higher, with iron and silicon as major impurities
    • 2000 series: Copper is the principal alloying element, with poor corrosion resistance unless clad
    • 3000 series: Manganese is the principal alloying element, generally non-heat treatable
    • 4000 series: Silicon is the principal alloying element, lowers melting temperature, and is used in welding and brazing
    • 5000 series: Magnesium is the principal alloying element, with good welding and corrosion-resistant characteristics
    • 6000 series: Silicon and magnesium form magnesium silicide, making alloys heat-treatable
    • 7000 series: Zinc is the principal alloying element, with high strength and heat-treatability when combined with magnesium and other elements

    Properties and Applications

    • 1000 series: Excellent corrosion resistance, high thermal and electrical conductivity, low mechanical properties, and excellent workability
    • 2000 series: Solution heat treatment, optimum properties equal to mild steel, but poor corrosion resistance unless clad
    • 3000 series: Moderate strength, good working characteristics, and high degree of resistance to corrosion
    • 4000 series: Limited heat treatment, used in welding and brazing
    • 5000 series: High temperatures or excessive cold working increase susceptibility to corrosion
    • 6000 series: Medium strength, good forming qualities, and corrosion-resistant characteristics
    • 7000 series: High strength, heat-treatable, and corrosion-resistant, with copper and chromium added

    Hardness Identification and Alloy Designation

    • Temper designation follows the alloy designation, separated by a dash (e.g., 7075-T6)
    • First digit in the alloy designation indicates the major alloying element:
      • 2xxx: Copper
      • 3xxx: Manganese
      • 4xxx: Silicon
      • 5xxx: Magnesium
      • 6xxx: Magnesium and silicon
      • 7xxx: Zinc
      • 8xxx: Other elements
    • Second digit in the alloy designation indicates alloy modifications
    • Last two digits in the alloy designation identify different alloys in the group

    Steel Properties

    • Strength, toughness, and resistance to wear and fatigue can be achieved through heat-treatment.
    • Chrome-vanadium with high carbon content is used for ball and roller bearings.
    • Molybdenum in small percentages is used in combination with chromium to form chrome-molybdenum steel, which has various uses in aircraft.

    Chrome-Molybdenum Steel

    • Raises the ultimate strength of steel without affecting ductility or workability.
    • Tough and wear resistant, and hardens throughout when heat-treated.
    • Especially adaptable for welding and used principally for welded structural parts and assemblies.
    • Has practically replaced carbon steel in the fabrication of fuselage tubing, engine mounts, landing gears, and other structural parts.

    Chrome-Molybdenum Steel in Aircraft Construction

    • Series containing 0.25 to 0.55 percent carbon, 0.15 to 0.25 percent molybdenum, and 0.50 to 1.10 percent chromium.
    • Deep hardening, easily machined, readily welded by either gas or electric methods, and adapted to high temperature service.

    Nickel Steels

    • Produced by combining nickel with carbon steel.
    • Steels containing from 3 to 3.75 percent nickel are commonly used.
    • Nickel increases the hardness, tensile strength, and elastic limit of steel without appreciably decreasing ductility.
    • Intensifies the hardening effect of heat treatment.

    Nickel Steels in Aircraft

    • SAE 2330 steel is used extensively for aircraft parts, such as bolts, terminals, keys, clevises, and pins.

    Chromium Steel

    • High in hardness, strength, and corrosion-resistant properties.
    • Particularly adaptable for heat-treated forgings, which require greater toughness and strength than may be obtained in plain carbon steel.
    • Used for articles such as the balls and rollers of antifriction bearings.

    Stainless Steel

    • The corrosion-resistant metal.
    • The anticorrosive degree is determined by the surface condition of the metal, as well as by the composition, temperature, and concentration of the corrosive agent.
    • The principal alloy of stainless steel is chromium.
    • 18-8 steel is commonly used in aircraft construction due to its high strength, corrosion resistance, and ability to be rolled, drawn, bent, or formed to any shape.

    Stainless Steel Applications

    • Fabrication of exhaust collectors, stacks, and manifolds, structural and machined parts, springs, castings, tie rods, and control cables.

    Chrome-Vanadium Steels

    • Made of approximately 18 percent vanadium and about 1 percent chromium.
    • Steel containing carbon in percentages ranging from 0.30 to 0.50 percent is classed as medium carbon steel.
    • SAE 1035 steel is used for certain rod ends and light forgings.

    High Carbon Steel

    • Steel containing carbon in percentages ranging from 0.50 to 1.05 percent.
    • The addition of other elements in varying quantities adds to the hardness of this steel.

    Series Designation Types

    • 10xx: Non-sulfurized carbon steels
    • 11xx: Resulfurized carbon steels (free machining)
    • 12xx: Rephosphorized and resulfurized carbon steels (free machining)
    • 13xx: Manganese
    • 23xx: Nickel 3.50%
    • 25xx: Nickel 5.00%
    • 31xx: Nickel 1.25%, chromium 0.65%
    • 33xx: Nickel 3.50%, chromium 1.55%
    • 40xx: Molybdenum 0.20 or 0.25%
    • 41xx: Chromium 0.50% or 0.95%, molybdenum 0.12 or 0.20%
    • 43xx: Nickel 1.80%, chromium 0.50% or 0.80%, molybdenum 0.25%
    • 44xx: Molybdenum 0.40%
    • 45xx: Molybdenum 0.52%
    • 46xx: Nickel 1.80%, molybdenum 0.25%
    • 47xx: Nickel 1.05%, chromium 0.45%, molybdenum 0.20 or 0.35%
    • 48xx: Nickel 3.50%, molybdenum 0.25%
    • 50xx: Chromium 0.25, or 0.40 or 0.50%
    • 50xxx: Carbon 1.00%, chromium 0.50%
    • 51xx: Chromium 0.80, 0.90, 0.95 or 1.00%
    • 51xxx: Carbon 1.00%, chromium 1.05%
    • 52xxx: Carbon 1.00%, chromium 1.45%
    • 61xx: Chromium 0.60, 0.80, 0.95%, vanadium 0.12%, 0.10% min., or 0.15% min.
    • 81xx: Nickel 0.30%, chromium 0.40%, molybdenum 0.12%
    • 86xx: Nickel 0.55%, chromium 0.50%, molybdenum 0.20%
    • 87xx: Nickel 0.55%, chromium 0.05%, molybdenum 0.25%
    • 88xx: Nickel 0.55%, chromium 0.05%, molybdenum 0.35%
    • 92xx: Manganese 0.85%, silicon 2.00%, chromium 0 or 0.35%
    • 93xx: Nickel 3.25%, chromium 1.20%, molybdenum 0.12%
    • 94xx: Nickel 0.45%, chromium 0.40%, molybdenum 0.12%
    • 98xx: Nickel 1.00%, chromium 0.80%, molybdenum 0.25%

    Monel

    • Adaptable to casting and hot or cold working, and can be successfully welded.
    • Has working properties like those of steel.
    • When forged and annealed, it has a tensile strength of 80,000 psi.
    • Can be increased by cold working to 125,000 psi.

    K-Monel

    • A nonferrous alloy containing mainly nickel, copper, and aluminum.
    • Corrosion resistant and capable of being hardened by heat treatment.
    • Nonmagnetic at all temperatures.

    Nickel and Nickel Alloys

    • Monel and Inconel are the two nickel alloys used in aircraft.
    • Monel contains about 68 percent nickel and 29 percent copper, plus small amounts of iron and manganese.
    • Inconel alloys of nickel produce a high strength, high temperature alloy containing approximately 80 percent nickel, 14 percent chromium, and small amounts of iron and other elements.
    • Inconel and stainless steel are similar in appearance and are frequently found in the same areas of the engine.

    Substitution of Aircraft Metals

    • Four requirements must be kept in mind when selecting substitute metals: maintaining the original strength of the structure, maintaining contour or aerodynamic smoothness, maintaining original weight, and maintaining the original corrosion-resistant properties of the metal.

    Metalworking Processes

    • Three methods of metalworking: hot working, cold working, and extruding.
    • The method used depends on the metal involved and the part required.

    Hot Working

    • Almost all steel is hot worked from the ingot into some form from which it is either hot or cold worked to the finished shape.

    Aluminum Bronzes

    • Wrought aluminum bronzes are almost as strong and ductile as medium carbon steel, and they possess a high degree of resistance to corrosion.
    • Readily forged, hot or cold rolled, and many react to heat treatment.
    • These copper base alloys contain up to 16 percent of aluminum (usually 5 to 11 percent), to which other metals, such as iron, nickel, or manganese, may be added.

    Cast Aluminum Bronzes

    • Have high strength combined with ductility and are resistant to corrosion, shock, and fatigue.
    • Used in bearings and pump parts.

    Manganese Bronze

    • An exceptionally high strength, tough, corrosion-resistant copper zinc alloy containing aluminum, manganese, iron, and occasionally, nickel or tin.
    • Can be formed, extruded, drawn, or rolled to any desired shape.
    • In rod form, it is generally used for machined parts for aircraft landing gears and brackets.

    Silicon Bronze

    • A more recent development composed of about 95 percent copper, 3 percent silicon, and 2 percent manganese, zinc, iron, tin, and aluminum.
    • Has high strength and great corrosion resistance.

    Steel Properties and Uses

    • Heat-treated steel has strength, toughness, and resistance to wear and fatigue.
    • Chromium-vanadium steel (SAE 6150) is used for making springs; chrome-vanadium with high carbon content (SAE 6195) is used for ball and roller bearings.
    • Molybdenum in small percentages is used in combination with chromium to form chrome-molybdenum steel, which has various uses in aircraft.

    Chrome-Molybdenum Steel

    • Raises the ultimate strength of steel without affecting ductility or workability.
    • Tough and wear-resistant, harden throughout when heat-treated.
    • Especially adaptable for welding, used principally for welded structural parts and assemblies.
    • Heat-treated SAE X4130 tube is approximately four times as strong as an SAE 1025 tube of the same weight and size.

    Inconel

    • Nickel-chromium-iron alloy closely resembling stainless steel (corrosion-resistant steel (CRES)) in appearance.
    • Used in aircraft exhaust systems.

    Nickel Steels

    • Produced by combining nickel with carbon steel.
    • Nickels increase the hardness, tensile strength, and elastic limit of steel without appreciably decreasing ductility.
    • Intensify the hardening effect of heat treatment.
    • SAE 2330 steel is used extensively for aircraft parts, such as bolts, terminals, keys, clevises, and pins.

    Chromium Steel

    • High in hardness, strength, and corrosion-resistant properties.
    • Particularly adaptable for heat-treated forgings, which require greater toughness and strength than plain carbon steel.

    Stainless Steel (Chrome-Nickel Steel)

    • Corrosion-resistant metal with a principal alloy of chromium.
    • The corrosion-resistant steel most often used in aircraft construction is known as 18-8 steel (18% chromium and 8% nickel).
    • Cold working may increase its strength.
    • Can be used for almost any part of an aircraft, such as exhaust collectors, stacks, and manifolds.

    Steel Designation Types

    • 10xx: Non-sulfurized carbon steels
    • 11xx: Resulfurized carbon steels (free machining)
    • 12xx: Rephosphorized and resulfurized carbon steels (free machining)
    • 13xx: Manganese
    • Other series designations have varying percentages of nickel, chromium, molybdenum, and carbon.

    Carbon Steel

    • Steel containing carbon in percentages ranging from 0.30 to 0.50% is classed as medium carbon steel.
    • Steel containing carbon in percentages ranging from 0.50 to 1.05% is classed as high carbon steel.

    Steel Properties and Uses

    • Heat-treated steel has strength, toughness, and resistance to wear and fatigue.
    • Chromium-vanadium steel (SAE 6150) is used for making springs; chrome-vanadium with high carbon content (SAE 6195) is used for ball and roller bearings.
    • Molybdenum in small percentages is used in combination with chromium to form chrome-molybdenum steel, which has various uses in aircraft.

    Chrome-Molybdenum Steel

    • Raises the ultimate strength of steel without affecting ductility or workability.
    • Tough and wear-resistant, harden throughout when heat-treated.
    • Especially adaptable for welding, used principally for welded structural parts and assemblies.
    • Heat-treated SAE X4130 tube is approximately four times as strong as an SAE 1025 tube of the same weight and size.

    Inconel

    • Nickel-chromium-iron alloy closely resembling stainless steel (corrosion-resistant steel (CRES)) in appearance.
    • Used in aircraft exhaust systems.

    Nickel Steels

    • Produced by combining nickel with carbon steel.
    • Nickels increase the hardness, tensile strength, and elastic limit of steel without appreciably decreasing ductility.
    • Intensify the hardening effect of heat treatment.
    • SAE 2330 steel is used extensively for aircraft parts, such as bolts, terminals, keys, clevises, and pins.

    Chromium Steel

    • High in hardness, strength, and corrosion-resistant properties.
    • Particularly adaptable for heat-treated forgings, which require greater toughness and strength than plain carbon steel.

    Stainless Steel (Chrome-Nickel Steel)

    • Corrosion-resistant metal with a principal alloy of chromium.
    • The corrosion-resistant steel most often used in aircraft construction is known as 18-8 steel (18% chromium and 8% nickel).
    • Cold working may increase its strength.
    • Can be used for almost any part of an aircraft, such as exhaust collectors, stacks, and manifolds.

    Steel Designation Types

    • 10xx: Non-sulfurized carbon steels
    • 11xx: Resulfurized carbon steels (free machining)
    • 12xx: Rephosphorized and resulfurized carbon steels (free machining)
    • 13xx: Manganese
    • Other series designations have varying percentages of nickel, chromium, molybdenum, and carbon.

    Carbon Steel

    • Steel containing carbon in percentages ranging from 0.30 to 0.50% is classed as medium carbon steel.
    • Steel containing carbon in percentages ranging from 0.50 to 1.05% is classed as high carbon steel.

    Steel Properties and Uses

    • Heat-treated steel has strength, toughness, and resistance to wear and fatigue.
    • Chromium-vanadium steel (SAE 6150) is used for making springs; chrome-vanadium with high carbon content (SAE 6195) is used for ball and roller bearings.
    • Molybdenum in small percentages is used in combination with chromium to form chrome-molybdenum steel, which has various uses in aircraft.

    Chrome-Molybdenum Steel

    • Raises the ultimate strength of steel without affecting ductility or workability.
    • Tough and wear-resistant, harden throughout when heat-treated.
    • Especially adaptable for welding, used principally for welded structural parts and assemblies.
    • Heat-treated SAE X4130 tube is approximately four times as strong as an SAE 1025 tube of the same weight and size.

    Inconel

    • Nickel-chromium-iron alloy closely resembling stainless steel (corrosion-resistant steel (CRES)) in appearance.
    • Used in aircraft exhaust systems.

    Nickel Steels

    • Produced by combining nickel with carbon steel.
    • Nickels increase the hardness, tensile strength, and elastic limit of steel without appreciably decreasing ductility.
    • Intensify the hardening effect of heat treatment.
    • SAE 2330 steel is used extensively for aircraft parts, such as bolts, terminals, keys, clevises, and pins.

    Chromium Steel

    • High in hardness, strength, and corrosion-resistant properties.
    • Particularly adaptable for heat-treated forgings, which require greater toughness and strength than plain carbon steel.

    Stainless Steel (Chrome-Nickel Steel)

    • Corrosion-resistant metal with a principal alloy of chromium.
    • The corrosion-resistant steel most often used in aircraft construction is known as 18-8 steel (18% chromium and 8% nickel).
    • Cold working may increase its strength.
    • Can be used for almost any part of an aircraft, such as exhaust collectors, stacks, and manifolds.

    Steel Designation Types

    • 10xx: Non-sulfurized carbon steels
    • 11xx: Resulfurized carbon steels (free machining)
    • 12xx: Rephosphorized and resulfurized carbon steels (free machining)
    • 13xx: Manganese
    • Other series designations have varying percentages of nickel, chromium, molybdenum, and carbon.

    Carbon Steel

    • Steel containing carbon in percentages ranging from 0.30 to 0.50% is classed as medium carbon steel.
    • Steel containing carbon in percentages ranging from 0.50 to 1.05% is classed as high carbon steel.

    Steel Classification

    • Steel containing 0.30-0.50% carbon is classified as medium carbon steel, suitable for machining or forging and requiring surface hardness.
    • Steel containing 0.50-1.05% carbon is classified as high carbon steel, with added elements increasing hardness.

    Series Designation Types

    • 10xx: Non-sulfurized carbon steels
    • 11xx: Resulfurized carbon steels (free machining)
    • 12xx: Rephosphorized and resulfurized carbon steels (free machining)
    • 13xx: Manganese 1.75%
    • 23xx: Nickel 3.50%
    • 25xx: Nickel 5.00%
    • 31xx: Nickel 1.25%, chromium 0.65%
    • 33xx: Nickel 3.50%, chromium 1.55%
    • 40xx: Molybdenum 0.20 or 0.25%
    • 41xx: Chromium 0.50% or 0.95%, molybdenum 0.12 or 0.20%
    • 43xx: Nickel 1.80%, chromium 0.5 or 0.80%, molybdenum 0.25%
    • 44xx: Molybdenum 0.40%
    • 45xx: Molybdenum 0.52%
    • 46xx: Nickel 1.80%, molybdenum 0.25%
    • 47xx: Nickel 1.05%, chromium 0.45%, molybdenum 0.20 or 0.35%
    • 48xx: Nickel 3.50%, molybdenum 0.25%
    • 50xx: Chromium 0.25, 0.40, or 0.50%
    • 51xx: Chromium 0.80, 0.90, 0.95, or 1.00%
    • 61xx: Chromium 0.60, 0.80, 0.95%, vanadium 0.12%, 0.10% min., or 0.15% min.
    • 81xx: Nickel 0.30%, chromium 0.40%, molybdenum 0.12%
    • 86xx: Nickel 0.55%, chromium 0.50%, molybdenum 0.20%
    • 87xx: Nickel 0.55%, chromium 0.05%, molybdenum 0.25%
    • 88xx: Nickel 0.55%, chromium 0.05%, molybdenum 0.35%
    • 92xx: Manganese 0.85%, silicon 2.00%, chromium 0 or 0.35%
    • 93xx: Nickel 3.25%, chromium 1.20%, molybdenum 0.12%
    • 94xx: Nickel 0.45%, chromium 0.40%, molybdenum 0.12%
    • 98xx: Nickel 1.00%, chromium 0.80%, molybdenum 0.25%

    Spark Testing

    • Spark testing is a method of identifying ferrous metals by their spark characteristics when held against a revolving grinding stone.
    • Each ferrous metal has its own peculiar spark characteristics.
    • Spark streams vary from a few tiny shafts to a shower of sparks several feet in length.

    Low Carbon Steel

    • Steel containing 0.10-0.30% carbon is classified as low carbon steel.
    • Equivalent SAE numbers range from 1010 to 1030.
    • Low carbon steel is used for making items such as safety wire, nuts, cable bushings, and threaded rod ends.
    • It is also used for secondary structural parts and clamps in sheet form and moderately stressed structural parts in tubular form.

    Hardening

    • Pure iron, wrought iron, and extremely low carbon steels cannot be appreciably hardened by heat treatment.
    • Cast iron can be hardened, but its heat treatment is limited.
    • In plain carbon steel, the maximum hardness depends almost entirely on the carbon content of the steel.
    • When the carbon content is increased beyond 0.85%, there is no increase in wear resistance.
    • Hardening treatment consists of heating the steel to a temperature just above the upper critical point, soaking, and then cooling rapidly by plunging into oil, water, or brine.

    Steel Classification

    • Steel containing 0.30-0.50% carbon is classified as medium carbon steel, suitable for machining or forging and requiring surface hardness.
    • Steel containing 0.50-1.05% carbon is classified as high carbon steel, with added elements increasing hardness.

    Series Designation Types

    • 10xx: Non-sulfurized carbon steels
    • 11xx: Resulfurized carbon steels (free machining)
    • 12xx: Rephosphorized and resulfurized carbon steels (free machining)
    • 13xx: Manganese 1.75%
    • 23xx: Nickel 3.50%
    • 25xx: Nickel 5.00%
    • 31xx: Nickel 1.25%, chromium 0.65%
    • 33xx: Nickel 3.50%, chromium 1.55%
    • 40xx: Molybdenum 0.20 or 0.25%
    • 41xx: Chromium 0.50% or 0.95%, molybdenum 0.12 or 0.20%
    • 43xx: Nickel 1.80%, chromium 0.5 or 0.80%, molybdenum 0.25%
    • 44xx: Molybdenum 0.40%
    • 45xx: Molybdenum 0.52%
    • 46xx: Nickel 1.80%, molybdenum 0.25%
    • 47xx: Nickel 1.05%, chromium 0.45%, molybdenum 0.20 or 0.35%
    • 48xx: Nickel 3.50%, molybdenum 0.25%
    • 50xx: Chromium 0.25, 0.40, or 0.50%
    • 51xx: Chromium 0.80, 0.90, 0.95, or 1.00%
    • 61xx: Chromium 0.60, 0.80, 0.95%, vanadium 0.12%, 0.10% min., or 0.15% min.
    • 81xx: Nickel 0.30%, chromium 0.40%, molybdenum 0.12%
    • 86xx: Nickel 0.55%, chromium 0.50%, molybdenum 0.20%
    • 87xx: Nickel 0.55%, chromium 0.05%, molybdenum 0.25%
    • 88xx: Nickel 0.55%, chromium 0.05%, molybdenum 0.35%
    • 92xx: Manganese 0.85%, silicon 2.00%, chromium 0 or 0.35%
    • 93xx: Nickel 3.25%, chromium 1.20%, molybdenum 0.12%
    • 94xx: Nickel 0.45%, chromium 0.40%, molybdenum 0.12%
    • 98xx: Nickel 1.00%, chromium 0.80%, molybdenum 0.25%

    Spark Testing

    • Spark testing is a method of identifying ferrous metals by their spark characteristics when held against a revolving grinding stone.
    • Each ferrous metal has its own peculiar spark characteristics.
    • Spark streams vary from a few tiny shafts to a shower of sparks several feet in length.

    Low Carbon Steel

    • Steel containing 0.10-0.30% carbon is classified as low carbon steel.
    • Equivalent SAE numbers range from 1010 to 1030.
    • Low carbon steel is used for making items such as safety wire, nuts, cable bushings, and threaded rod ends.
    • It is also used for secondary structural parts and clamps in sheet form and moderately stressed structural parts in tubular form.

    Hardening

    • Pure iron, wrought iron, and extremely low carbon steels cannot be appreciably hardened by heat treatment.
    • Cast iron can be hardened, but its heat treatment is limited.
    • In plain carbon steel, the maximum hardness depends almost entirely on the carbon content of the steel.
    • When the carbon content is increased beyond 0.85%, there is no increase in wear resistance.
    • Hardening treatment consists of heating the steel to a temperature just above the upper critical point, soaking, and then cooling rapidly by plunging into oil, water, or brine.

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