Material Properties of Alloys

Vocabulary flashcards for review

Steel

A hard, strong grey or bluish-grey alloy of iron with carbon and usually other elements, used as a structural and fabricating material.

Cast Irons

Ferrous material with 2.14-4 wt% C

Steels

Steel with 0.04-1.7 wt% C

High carbon steels

Steels with 0.6-1.4 wt% C

Medium carbon steels

Steels with 0.25-0.6 wt% C

Low carbon steels

Steels with 0.04-0.25 wt% C

Stainless steel

Iron with 13-26% Cr

Tool steel

Iron with W, Co

Low alloy steel

A1 = 727°C (eutectoid temp)

a-iron (ferrite)

bcc; Soft; Ferromagnetic to 1043 K; Max 0.2 % carbon

Fe3C (cementite)

Orthorhombic; Hard; Ferromagnetic to 480 K

g-iron (austenite)

fcc; High temp phase

Eutectoid

A reaction where a single solid phase breaks down into two solid phases during cooling

Cooling at eutectoid composition

Carbon diffuses out of some regions so that ferrite forms and into other regions to form cementite

Pearlite

A layered structure of ferrite and cementite

Hypoeutectoid compositions

C < 0.8 wt%, mixture of ferrite and pearlite

Hypereutectoid compositions

C > 0.8 wt% (up to 6.67 wt%), mixture of pearlite and cementite

Martensite

High strength, hardness and toughness

Tempering

Treatment at low temperature relaxes structure and allows carbides to form

Wrought steel

Steels shaped by deformation

High Strength-Low Alloy (HSLA) steels

Have small Al, Nb and V additions which gives grain size reduction and Makes carbide and nitride second phase precipitates

Manganese steel

Steel undergoing a phase change forming martensite at the surface when abraded and is very wear resistant, yet tough

2xxx Nickel steels

SAE designation when Includes Invar and strongly magnetic steels

3xxx Nickel-chromium steels

SAE designation when Tough, hard

4xxx Molybdenum steels

SAE designation when High toughness

5xxx Chromium steels

SAE designation when Stainless steel with Cr > 12 wt% (max 1.2 wt% C)

6xxx Chromium-vanadium steels

SAE designation when High wear resistance, high-speed steel

7xxx Tungsten steels

SAE designation when Exceptional heat, wear and corrosion resistance

8xxx Nickel-chromium-molybdenum steels

SAE designation when High toughness, corrosion resistance

9xxx Silicon-manganese steels

SAE designation when Includes magnetic materials for electrical transformers