MEC 147N Lecture 2: Ferrous Metal Alloys

Iron-based alloys containing a maximum of 1.0 wt% carbon and optional alloying elements. The strength and ductility of these alloys vary significantly depending on the carbon content and heat treatment applied.

Steels that have a carbon content of less than 0.25 wt% and are not strengthened by heat treatments that form martensite. They are soft and weak but exhibit excellent ductility and toughness.

The ability of a material to resist external forces without failure.

The capacity of a material to deform plastically before reaching its breaking point.

The resistance of a material to localized plastic deformation, such as a scratch or indent.

A type of steel containing less than 0.25 wt% carbon and not strengthened by heat treatment. It is soft, weak, but very ductile and easy to work with.

An increase in the strength of a material by mechanical deformation, usually through hammering or rolling.

A material with the ability to absorb significant energy before fracturing.

A process that allows metal to be shaped by applying heat and controlled cooling.

A type of steel with a carbon content between 0.25% and 0.60% that can be strengthened by heat treatment.

Steels containing only small amounts of impurities, including carbon and manganese.

The first two digits of the AISI/SAE designation indicate the alloy content. 10 represents plain carbon steels, while other two-digit combinations like 13, 41, 43 indicate alloy steels.

The last two digits of the AISI/SAE designation represent the carbon content multiplied by 100. For example, 1060 steel contains 0.60 weight percent carbon.

Steels containing specific amounts of alloying elements like copper, vanadium, nickel, and molybdenum, enhancing their strength compared to plain low-carbon steels.

They are more resistant to corrosion than plain carbon steels in normal environments, making them suitable for structural applications like bridges and towers.

Achieved by heat-treating medium-carbon steels with chromium, nickel, and molybdenum, resulting in stronger alloys but with reduced ductility and toughness.

They have carbon contents ranging from 0.60 to 1.4 wt%. They are known for their hardness, strength, and limited ductility.

A specific type of high-carbon steel, which typically includes alloying elements like chromium, vanadium, tungsten, and molybdenum. These steels are used for tools and dies due to their superior strength and wear resistance.

Ferrous alloys containing over 2.14 wt% carbon, typically between 3.0 and 4.5 wt%. These alloys are usually brittle and most conveniently fabricated through casting.

Cast irons containing graphite flakes, formed during slow cooling, which give the fractured surface a gray appearance. They are known for their vibration damping properties and high fluidity at casting temperature.

The presence of graphite flakes in gray cast iron provides excellent damping properties. This means it absorbs vibration energy effectively.

A type of cast iron where magnesium (Mg) and/or Ce or Ca are added before casting, producing a microstructure with nodules instead of flakes. This results in improved ductility and mechanical properties compared to gray cast iron.

Steels that are highly resistant to corrosion, especially in the ambient atmosphere. They contain at least 11 wt% chromium, and often nickel and molybdenum for enhanced corrosion resistance.

Stainless steels are classified based on their microstructure: martensitic, ferritic, or austenitic. Each class has distinct characteristics and properties.

A type of stainless steel characterized by its high strength and hardness due to the martensitic phase. It finds applications in cutting tools, dies, and high-strength wire.

A type of stainless steel known for its good corrosion resistance and ductility. It commonly contains chromium and sometimes molybdenum.

A type of stainless steel characterized by its excellent ductility, weldability, and resistance to corrosion, even at high temperatures. It contains large amounts of nickel.

Alloying elements, like chromium and nickel, that are added to steel to enhance specific properties like corrosion resistance, strength, and hardness.

Graphite in cast iron forms as nodules or spheres instead of flakes, giving the alloy high ductility and machinability.

A type of cast iron formed by rapidly cooling the molten metal, preventing graphite flakes from forming. This results in a very hard and brittle material with high wear resistance.

Produced by heat treatment of white cast iron. It is a more ductile and malleable form of cast iron, often used for applications requiring strength and impact resistance.

The formation of cementite (Fe3C) within the microstructure of cast iron, resulting in a white, hard and brittle material.

A type of cast iron where the graphite flakes are oriented randomly, resulting in an isotropic material with good wear resistance.

A type of cast iron where the graphite flakes are aligned in a specific direction, resulting in a material that is strong along the grain direction but weaker perpendicular to it.

The process of rapidly cooling molten cast iron, preventing the formation of graphite flakes and resulting in a hard and brittle material with high wear resistance.

The ability of a material to deform plastically before fracture, meaning it can bend and stretch without breaking.

The resistance of a material to scratching or indentation, often determined by a hardness test.