EASA B1.1 Module 6.1 Ferrous Metal PDF

EASA B1.1 : MODULE 6.1 FERROUS METAL 12 October 2024 Prepared By: M.Azlan Shafie 2  1- Aluminium alloys 2. Magnesium alloys 3. Alloy steel ~Save weight - light 4.Composite Materials...

EASA B1.1 : MODULE 6.1 FERROUS METAL 12 October 2024 Prepared By: M.Azlan Shafie 2  1- Aluminium alloys 2. Magnesium alloys 3. Alloy steel ~Save weight - light 4.Composite Materials ~ Strong ~ Not corrosive 5. Wood ~Safety Factor 6. Heavy alloys – copper alloy 3 Prepared By: M.Azlan Shafie Most materials in aircraft construction are non-ferrous, but, others like:  Aircraft engines, engine mounting, hydraulic lines, control cables and some other parts are made from ferrous metals. A metallic material that contains at least 50% iron is classified as a ferrous metal or alloy. The simplest ferrous metal is plain carbon steel, consisting of less than one percent carbon. Prepared By: M.Azlan Shafie 4  Ferrous and Non- Ferrous Metals Iron as the Base metal Base other than iron ( More than 50 % Iron ) Aluminium Copper Iron is the most Magnesium common metals used Light Alloys Heavy Alloys Iron Ore is mined producing IRON (Pig Iron)  GENERAL CHARACTERISTIC OF METAL The properties of a metal, which influence its suitability as a material for engineering use. 1. Brittleness  The property of a metal to break when bent, defamed or hammered.  It is the resistance to change in the relative position of the molecules within the material.  Cast iron, cast aluminium and very hard steel are examples of brittle metals. Prepared By: M.Azlan Shafie 2. Conductivity  The characteristic of a material, which makes it possible for it to transmit heat or electrical energy by conduction. 3. Ductility  The property, which allows metal to be drawn into thinner sections without breaking.  Ductility allows materials like aluminium and copper to be drawn into very small wires. 4. Elasticity  The capability of an object a material to be stretched and to recover it’s size and shape after it’s deformation. Prepared By: M.Azlan Shafie 5. Malleability The characteristic of a material that allows it to be stretched and shaped by beating with a hammer or passing through rollers without breaking. 6. Plasticity The property of assuming a new shape when subjected to pressure. The new shape being retained after the pressure has been discontinued. 7. Tenacity This is the resistance a material offers against being pulled apart Materials which have good tenacity have a high tensile strength. Tensile strength of steel is high where as that of lead is low. Prepared By: M.Azlan Shafie 8. Toughness Is the resistance to fracture by blows, bending or twisting loads. Tough materials usually have high tenacity combined with good ductility. Toughness decreases with heating. 9. Fatigue A weakening or collapse of metal due to the continuous application of alternating or varying stresses. Prepared By: M.Azlan Shafie 10. Hardness  The ability of a metal to resist scratch or indent by another metal or the ability to resist wears by abrasion. Aircraft Pressure Plate 11.Strength  The definition of strength would be the ability of a material that affects the strength it exhibits. Prepared By: M.Azlan Shafie  METALS (IRON) By virtue of their wide range of mechanical, physical, and chemical properties, ferrous metals and alloys are among the most useful of all metal. Ferrous metals and alloys contain iron as their base metal;  The general categories are carbon and alloy steels, stainless steels, tool and dies steels, cast irons, and cast steels. Prepared By: M.Azlan Shafie  IRON IS USED IN THREE FORMS CAST IRON WROUGHT IRON STEEL Pig iron re melted Purified pig iron Iron which contain and poured into a product ( Almost no carbon content) Carbon up to 1.7 % shape. - Up to 0.04 % only (0.1 – 1.7 % ) Pig and Cast iron is of similar constituents Prepared By: M.Azlan Shafie Cast iron Wrought iron Steel Hinge Prepared By: M.Azlan Shafie Production of Metals (Iron)  Raw material of Iron Ore, Coke and limestone are smelted in the Blast Furnace and Pig Iron is produce.  Pig iron reheated and refined in a small furnace called a cupola.  It produces grey cast iron, provided the liquid cast iron is allowed to cool slowly.  Grey cast iron contains about 3½ % carbon, which makes the cast iron brittle.  It fractures easily from sharp blows.  It has a grey crystalline colour where fractured.  It is used to make large pipes, steam radiators, water hydrants, frames for machines, etc. Prepared By: M.Azlan Shafie Iron Ores Blast Furnace Coke Limestone rock Prepared By: M.Azlan Shafie If liquid cast iron is rapidly cooled or chilled it would produce extremely hard cast irons. The carbon content ranges from about 2% to 3½ %. White cast iron is an example of hard cast irons. It is so hard that it cannot be machined, except by grinding. It's use is limited to castings requiring the surfaces to with stand abrasion and wear. Prepared By: M.Azlan Shafie White cast iron Prepared By: M.Azlan Shafie Prepared By: M.Azlan Shafie Prepared By: M.Azlan Shafie Pig Iron When the blast furnace is emptied, the melted iron flows out into a through and then into sand moulds. When it cools pigs are formed The moulds used in forming pig iron are a number of parallel trenches connected by a channel running at right angles to them. These are called ‘pigs’ , they are connected at one end to the long bar called the Sow (Mother pig) 93 % pure iron, 3 – 5 % Carbon Remainder –Silicon , Phosporous , Sulphur,Manganese Prepared By: M.Azlan Shafie Pig Iron Application and Use of Metals Application and Use of Metal If carbon is added to iron in percentages ranging up to approximately 1 percent, the product is vastly superior to iron and is classified as carbon steel. A base metal (such as iron) to which small quantities of other metals have been added is called an alloy. The addition of other metals will changes and improves the chemical and physical properties of the base metal for a particular use.  An Alloy An intentional mixture of two or more elements in which the major constituent is a metal A single metallic One or more substance which alloying elements constitutes more which may be than 50% of the present in large total mass or extremely small amounts By varying the nature and quantities of the alloying elements the properties of the steel can be controlled Table 1.1: Examples of metals, its terminology and the uses  STEEL Steel Steel is iron, which contains carbon in any amount up to about 1.5%. Carbon Steel There are two types of steel Alloy Steel Carbon Steels  Depends on carbon content itself for hardness. Dead Mild Steel Mild Steel (Low Carbon Steel) Four main groups Medium Carbon Steel High Carbon Steel (Tool Steel)  Four Main Group Of Carbon Steel Table 1.2: Four Group of Carbon Steel Alloy Steel Is harder than High Carbon Steel and depends on other alloying elements for it’s hardness and strength. Very suitable for making cutting tools that can withstand high speed and temperature. The following element when added will give the desired results. 1. Silicon Silicon when used as an alloying element has a strengthening effect. 2. Manganese Manganese when added, will give strength and toughness to steel. 3. Nickel Nickel when added, will give higher tensile strength together with increased ductility. 4. Chromium Chromium will give hardness to steel, toughens it, make the grain finer and causes it to resist rust. 5. Molybdenum Molybdenum, when added, will adds strength and hardness to steel and causes it to withstand heat and blows. 6. Vanadium Vanadium will gives lightness, toughness and strength and makes fine grain in steel. Vanadium steel can withstand great shocks.  In general, steel is a form of iron and it contains less carbon than cast iron, but considerably more than wrought iron The carbon content is from 0.03 to 1.7 percent. Basic carbon steels are alloyed with other elements, such as chromium and nickel, to increase certain physical properties of the metal. Steel has tensile strength of 45,000 psi (310,275 kPa) for low- carbon steel, 80,000 psi (551,600 kPa) for medium-carbon steel, 99,000 psi (692,605 kPa) for high-carbon steel, and 150,000 psi (1,034,250 kPa) for alloyed steel; and a melting point of 2800° F (1538°C). Some carbon Add carbon Wrought iron is taken from To + pig iron by Wrought Iron Pig iron burning + Scrap metals Melt them and control the amount of carbon content  Methods of Making Steel Open Hearth Furnace Bessemer Converter Crucible Furnace There are 5 basic ways of making steel Electric Furnace Basic Oxygen Process (BOP)  The 3 ways of making steel. 2. Open-Hearth Furnace 1. Bessemer Converter 3. Electric Furnace 1. Bessemer Converter This method is a quick way to make steel. The carbon and other impurities are burnt out of melted pig iron by blowing a current of cold air through it. This causes the carbon in the pig iron to unite with the oxygen in the air. When this happens, a more forceful burning takes place, burning out nearly all of the carbon. When the flame dies out, it is a sign that most of the carbon has been burnt out, and the air is then shut off. The exact amount of carbon necessary is then thrown in, thus making steel. This melted steel is poured into large buckets called ladles. Through a hole at the bottom of the ladle, the melted steel is then poured into ingot moulds, which are forms for making the steel into blocks. Bessemer Converter 2. Open Hearth Furnace This method is better than the Bessemer method because the melted metal can be tested for carbon content and more carbon can be added at any time during the heating. The Open Hearth Furnace is very similar to a Baker’s Oven. Pig iron, wrought iron, and old scraps of iron and steel are placed on a saucer- shaped hearth. Hot air and gas are used for heating. The flames touch the metal from above creating a very high temperature to keep the iron in a liquid form. Samples are taken to determine the correct amount of carbon desired. When the melted metal contains the right amount of carbon, it is poured into ingot moulds, and kept in the soaking pit at a high temperature. They may be rolled, drawn, or extruded in the next forming step. Open Hearth Furnace 3. Crucible Furnace The crucible process is the oldest method used for making high carbon steel and alloy steel. High-carbon steel is made by melting wrought iron and scrap steel in a crucible - a melting pot shaped like a barrel, made of graphite or clay, which can withstand great heat. The amount of carbon desired is then placed on top of the wrought iron and steel. A cover is placed tightly over the top, and a number of these crucibles are put in a hot furnace. The melted iron mixed with the carbon, thus making steel. The melted steel is then poured into ingot moulds. Alloy steel is made the same way except that additional materials such as chromium, vanadium, etc. are also put in the crucible The crucible furnace has been almost completely replaced by the electric furnace, which is a large arc-heated crucible. Crucible Furnace 4. Electric Furnace The electric furnace is used when close control of temperature and amounts of alloying elements is important. Higher temperatures can be reached with the electric furnace than are possible with other steel-making furnaces. High carbon steel, special alloy steel, and high-speed steel are made in this way. They are used for cutting tools, dies, etc. Electric arc furnaces give very close control of the grain structure of steel. Electric Furnace 5. Basic Oxygen Process Designed expressly to get the best results with oxygen in steel making, the basic oxygen furnace can produce steel amazingly fast. In a typical Basic Oxygen Process;  The charge of iron ore, steel scrap, and molten iron is refined into steel.  This is by blowing oxygen down from the top through a vertical lance extending to within five feet or so from the bath. During the blow, burnt lime, etc. are added as fluxing agents. Basic Oxygen Process Identification Coding for Steel Most general-purpose steels used for aircraft work are wrought steel products. In addition to the standard carbon and alloy steels, a substantial number of heat and corrosion resistant steels are used as well. SAE – Society of Automotive Engineers Table 1.3 Identification Code From Table 1-3 Example : 10xx  1st Digit  Indicates general classification  1 indicates carbon steel. From Table 1-1 Example : 2330 Indicates approximate percentage of the principal alloying element  2nd Digit 3 indicate 3% nickel  Last 2 digits Indicates approximate amount of carbon in one-hundredths of 1%. Identification Coding for Steel A. For ordinary carbon steel, the higher the carbon content, the greater is the hardness as well as brittleness. B. High carbon steels are used for cutting tools, springs, etc. CARBON Greater Hardness And Brittleness C. The most commonly used steel for aircraft structural purposes is SAE 4130 chromium- molybdenum (Chrome-moly) steel.  When properly heat-treated, it is approximately four times as strong as 1025 mild-carbon steel.  The tensile strength of 4130 steel will range from 90,000 psi to more than 180,000 psi depending upon heat treatment. hardenable easily machined heat treatable SAE 4130 readily weldable easily worked withstand high temperature Identification Coding for Steel The nickel-steels, SAE 23xx and 25xx contain from 3.5 to 5% nickel and a small percentage of carbon. The nickel increases the strength, hardness and elasticity of the steel without affecting the ductility. Nickel steel is used for making nuts, bolts, clevis pins and screws. Nickel-chromium and Chromium-Vanadium steels are used where still greater strength, hardness, and toughness are required. Such steels are often found in highly stressed machine parts, such as gears, shafts, spring and bearings. HEAT TREATMENT OF STEEL The internal structure of most forms of steel can be varied by carefully controlled cycles of heating and cooling known as……. Heat Treatment The object of heat treatment is to produce certain properties inherent in the untreated material and to reduce other less desirable properties.  925 o C 860 o AUSTENITE 906 o C 830 o UCT 800 o 780 o o 810 o 760 Ferrite + 745 o Cementite + 730 o Austenite Austenite 727 o 725 o C LCT 723 o C FERRITE + PEARLITE Pearlite + (Hypoeutectoid) Cementite TEMP (Hypereutectoid) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 CARBON CONTENT  Heat Treatment Processes The properties of steel can be varied over a wide range by heat treatment. The four main forms of heat treatment used on steel are :  The cycle of events in heat treating. 1.Controlled Heating 2.Soaking or Holding 3.Controlled Cooling (Quenching) The process of keeping Heating metal to a metal at an evaluated temperature Returning the metal temperature for a definite within or above it’s period of time. to room critical temperature. temperature So that it can become by means of air, thoroughly saturated water, oil, brine. with heat and the necessary changes in grain structure can take place. Annealing is a softening process 1) To relieve internal stress. 2) To bring the steel to the softest possible condition when cold. 3) To refine grain structure.  Two Methods of Annealing 1. Full Annealing Heat steel to between 300 and 500 C. above UCT of the steel Soak at this temperature approximately ½ to 1 hr. per inch thickness( To permit recrystallization to occur). Cool the steel very slowly by leaving it in the steel furnace and switch –off the furnace 2. Process Annealing Heat steel to between 5200 and 6200 C. Soak at this temperature ( To permit recrystallisation to occur). Cool the steel very slowly. NORMALISING  The purpose for normalizing is to : Produce maximum refinement of the grain structure. Relieve stress set up by machining, welding, etc. Normalizing is also used prior to other heat treatment process to ensure a fine grain structure. The normalizing process consists of : Heating the steel to between 300 to 800 C above UCT. Soaking for ½ to 1hour per inch of thickness. Cooling in still air. HARDENING Hardening produces a fine grain structure, great hardness, maximum tensile strength and minimum ductility. *Heat steel above the critical temperature *Soak between 15 to 30 minutes The hardening process *Rapid quenching through suitable medium Quenching medium used are : ~ Brine ( Salt Water or Sodium Chloride ) ~ Water ~ Oil ~ Air CASE HARDENING  Case hardening treatments are given to iron base alloys to produce a hard, wear-resisting surface, and at the same time, to leave the core of metal tough. Three common methods of case hardening. Carburizing Cyaniding Nitriding This is a fast method of producing Soak the metal at an evaluated surface hardness. Accomplished by soaking temperature while in contact with rich special alloy steels at carbonaceous material. temperatures below the The steel is immersed in a critical point in anhydrous Molten bath of cyanide salt. ammonia. or Nitrogen from the ammonia is absorbed into the surface of the steel as iron nitride and produces hardness on the surface. Powdered cyanide may be applied to the surface of the heated steel. TEMPERING  Tempering is often called drawing. It relieve internal strain in hardened steel and increases its toughness. Hardened steel is tempered to increase its toughness so that it will not crack or fracture under heavy stress, vibration or impact. Methods of tempering : *Heat the metal to a temperature below the LCT. *Soak between 1 to 1 1/2 hours. *Cool in air or quenched in water, oil or brine. The Purpose of Heat Treatment  Heat treatment is the process used to hardens or strengthens metal.  It will make the metal stronger and more resistant to impact  Heat treatment also can make a metal softer and more ductile.  The following are the types of heat treatment processes. 1. Hardening Process, which makes steel harder. 2. Tempering Process, which relieves internal strain in, hardened steel and thus increases it’s toughness. 3. Annealing Process, which is used to soften and improve machinability of hardeners steel. 4. Normalizing Process, which involves heating steel to the normalizing temperature soaking it at this temperature for a period of time and allowing it to cool in air. 5. Case Hardening Process, which involves hardening a thin surface layer on steel, while the inner layer remains quite soft. Uses of Different Heat Treated Materials All metals and alloys do not respond to heat treatment. Ferrous metals, iron and steel, can usually be heat-treated. Some alloys of aluminium are strengthened by heat treatment, but cold working must harden others. The high-temperature nickel-base alloys can be heat treated in some cases, depending upon their composition. The temperatures and processes of heat treatment vary considerably among the different metal. Uses of Different Heat Treated Materials The hardening of metal by heat treatment is usually the result of one of two phenomena. Some metal are allotropic, that is, their lattice structure will change at elevated temperatures. Allotropic - of or related to or exhibiting allotropism; "carbon and sulfur and phosphorus are allotropic elements" Steel is hardened through this process. Uses of Different Heat Treated Materials Aluminium is not allotropic. The hardening of aluminium is accomplished by alloying an element that is soluble only at higher temperature. At lower temperature, the alloy precipitates as a metallic compound, producing hardening effects. END OF 6.1: Anodic Treatment U.S Military specification MIL-A-8625 R covers three types of anodising. Type 1 – Chromic Anodise Coating  Chromic anodise coating will vary from a light to a dark grey colour depending on the alloy.  This coating is given a chromate treatment to seal the surface. Type 2 – Sulphuric Anodise Coating  Sulphuric anodise coating is the best coating for dying not dyed coating.  It will have a dull yellow-green (gold) appearance when sealed with a chromate treatment. Type 3 – Hard Anodising Coating  Hard anodising coating can be used as an:  electrical insulation coating  abrasion-resisting coating  Such devices use this type of anodising are:  hydraulic cylinders  actuator cams.  Objective: - At the end of this lesson the student will be able to identify the manufacturing methods of corrosion treatment. Corrosion Treatment During Manufacture: Metal Surface Treatment Cadmium Plating Cadmium plating is a non-porous, electrolytically deposited layer of cadmium that offers high corrosion resistance for steel Three types of cadmium plating are considered in this specification: Type 1  This type is pure silver-coloured cadmium plate without supplementary treatment  This type of cadmium coating was used on all steel aircraft hardware in the past. Type 2  This type consists of type 1 plating followed by a chrome treatment.  Type 2 plating is a light to dark gold colour.  It has improved corrosion resistance.  Procurement specifications for most aircraft now specify type 2 plating. Type 3  This is type 1 coating followed by a phosphate treatment.  It is used mainly as a paint base. Alodizing  Alodizing is a simple chemical treatment for all aluminium alloys  Use to increase their corrosion resistance and to improve their paint bonding qualities. Anodising  A formation of a hard, unbroken film of aluminium oxide on a surface of an aluminium alloy.  This hardens the surface, reduces porosity, increases abrasion resistance and give high dielectric strength. Objective: - At the end of this lesson the student will be able to identify corrosion. Corrosion Prone Areas  Some of the sections are most of the trouble areas common to all aircraft. They are: - Battery compartments and Battery vent openings Exhaust Tail Area Bilge Areas  landing gear Corrosion Prone Areas Wheel well corrosion area  Corrosion Prone Area Engine frontal areas and Water entrapment areas cooling air vents  Corrosion Prone Area External skin areas Wing flap and spoiler recesses Fwd and aft wing spars Wing flap and spoiler recesses  Example of other corrosions Blocked drain passages resulted F-16 Aircraft Main Fuel Shutoff Valve in accumulation of corrosion contaminates Objective: - At the end of this lesson the student will be able to perform a repair of corrosion parts. Corrosion Treatments During Repair Wire Brush Sand Buffers Blasting Parts made of carbon alloy steel and not highly stressed can be cleaned with: Steel Wool Abrasive paper Corrosion Treatments During Repair If corrosion remains in pits and crevices it may be necessary to use chemical inhibitors to arrest further corrosion. Unpainted steel parts are often coated with rust-inhibiting oil greases. Corrosion Treatments During Repair Structural Aluminium Alloy parts that have suffered severe intergranular corrosion must usually be replaced because of the loss of strength in the parts. Sometimes a small amount of intergranular corrosion can be removed from the outer surface of a part but treated chemically and then refinished. Magnesium parts are chemically treated with a 10% chromic-acid solution to which has been added a small amount of sulphuric acid.  FATIGUE Objective: - At the end of this lesson the student will be able to identify metal fatigue. Fatigue Fatigue is a weakening or collapse of metal due to the continuous application of alternating or varying stresses. Fatigue is a natural phenomenon and cannot be prevented. The ability to correctly predict it’s effects and take necessary action is the problem faced by aircraft design and maintenance personnel. Different metals have different fatigue characteristics. Fatigue is also affected by design characteristics, such as changes in cross sectional areas, holes, notches, and so on. Fatigue cracking will expose unprotected metal to the elements, which increases the possibility of corrosion. Fatigue Once begun, the constant working and growth of the fatigue cracks enhance the continued spread of corrosion. The combination of corrosion and fatigue can generate serious structural problems in a short period. With the aging of the airline fleet, the maintenance personnel role in detecting and preventing such problems has taken on an added significance. Prepared By: Mohd Ezwani Kadir 96