MMET 207 FINAL REVIEW QUESTIONS
Stainless Steels - Answers :Alloys of Fe, Cr, and other elements that resist corrosion
The minmum amount is 11.5%Cr for stainless steels
(Increasing Cr) = (Decreases Corrosion)
Much Exhibit Passivity
Stainless Steels (3 Types) - Answers :- Ferritic
- Martensitic
- Austenitic
Sigma Phase - Answers :- a hard brittle compound of 50 atomic % Fe and 50 atomic %
Cr
- It is an undesirable phase, reduces corrosion resistance, lowers mechanical properties
- limiting factor of Cr
*Ferritic Steels*
- structure
- carbon contents
- chromium contents
- hardenable
- weldability and notch sensitivity
- magnetic?
- other props - Answers :- BCC Structure
- Normally less than 0.2% C
- Cr contents (16 - 20%)
- Non-Hardenable (cannot form martensite through heat treating)
- Poor Weldability and Notch Sensitivity
- Magnetic (Ferrite)
- Excellent Corrosion Resistance in Seawater
- Not very susceptible to stress corrosion cracking
Applications of Ferritic Steels - Answers :- Atmospheric Corrosion
- Elevated Temperatures
- Decorative Applications
Notch Sensitivity - Answers :The extent to which the sensitivity of a material to fracture
is increased by the presence of a surface inhomogeneity such as a notch, a sudden
change in section, a crack, or a scratch
What does adding more Cr and N do to the ternary diagram? - Answers :Expands the
gamma loop
,*Martensitic Steels*
- structure
- carbon contents
- chromium contents
- hardenable
- weldability and notch sensitivity
- magnetic?
- other props - Answers :- BCT Structure
- High Carbon (up to 1.2%)
- Cr content (12 - 18%)
- Hardenable
- Poor Weldability and Notch Sensitivity
- Magnetic
- Cr Carbides (Holds Edges)
- Will have a phase change (Martensitic Stucture)
- use oil or air quench and its considered non equilibrium cooling
- high carbon content used to further expand gamma loop so it will transform to
Austenite, making quench hardening possible
- Large Cr Contents allow this steel to reach 100% martensite with as low as 0.7% C
during hardenability
Applications of Martensitic Steels - Answers :- Structural Components
- Tooling Applications
- Cutting and Surgical Devices
*Austenitic Steels*
- structure
- magnetic?
- carbon contents
- chromium contents
- Nickel Contents
- hardenable
- weldability and notch sensitivity
- other props - Answers :- FCC
- Non-Magnetic
- Very low C
- Cr typically 16-26%
- Nickel 8-24%
- Non-Hardenable
- Weldable
- Harden through cold working
,Alloying Elements: Fe, Cr, C, Ni
(Austenizer) (Change on X-axis)
Applications of Austenitic Steels - Answers :- Chemical Processing
- Tanks
- Piping
- Welding Structures
18/0 Ferritic
18/18 Austenitic
18/10 - Answers :18% Cr, 0% Ni
18% Cr, 18% Ni
18% Cr, 10% Ni
Chromium Iron - Answers :- hard sharp edged
- used in cutting applications
- hard to resharpen
3XX - Answers :Austenitic Steels
4XX - Answers :Either Martensitic or Ferritic
Suffixes (A, B, C) most carbon to least carbon (order of hardness) - Answers :C, B, A
F and S - Answers :Improves machinability
#'s of Ferritic Steels - Answers :430, 430F, and 446
430 - Answers :Basic type, Cr 17%
- For rust resistant on decorative and nonfunctional parts
430F - Answers :S added to improve machinability
446 - Answers :Cr much higher for improved scaling resistance
#'s of Martensitic Steels - Answers :403, 410, 416, 420, 440C
403 - Answers :Cr 12% adjusted for special physicals
410 - Answers :basic type, Cr 12%
416 - Answers :S added for machinability
- used for jigs, fixtures, and base plates
, 420 - Answers :C higher for cutting purposes
- used for tools that don't need wear resistance
440C - Answers :C higher for cutting purposes (wear resistance)
- used for cutting devices, devices, punches, dies
#'s of Austenitic Steels - Answers :302, 303, 304, 304 L, 316, 316 L
302 - Answers :Basic type, Cr 18% Ni 8%
303 - Answers :S added for machinability
- dont want to weld this (S)
- used for fasteners and and shafts
304 - Answers :C lower to avoid carbide precipitation
- lower carbon content to improve weldability
- used for chemical immersion
304L - Answers :C lower for welding application
- even lower carbon content
- used for chemical immersion
316 - Answers :Mo added for corrosion resistance
- used for chemical immersion
316L - Answers :Mo added and less C for welding applications
- used for chemical immersion
Density of Stainless Steels - Answers :about the same as carbon steels
Structure of Stainless Steels - Answers :Ferritic = Magnetic
Austenitic = Non-Magnetic
Martensitic = Magnetic
Conductivity and Electrical Resistivity of Stainless Steels - Answers :Poor conductors
Thermal Conductivity = less than 1/2 that of carbon steels
Stainless Steels - Answers :Alloys of Fe, Cr, and other elements that resist corrosion
The minmum amount is 11.5%Cr for stainless steels
(Increasing Cr) = (Decreases Corrosion)
Much Exhibit Passivity
Stainless Steels (3 Types) - Answers :- Ferritic
- Martensitic
- Austenitic
Sigma Phase - Answers :- a hard brittle compound of 50 atomic % Fe and 50 atomic %
Cr
- It is an undesirable phase, reduces corrosion resistance, lowers mechanical properties
- limiting factor of Cr
*Ferritic Steels*
- structure
- carbon contents
- chromium contents
- hardenable
- weldability and notch sensitivity
- magnetic?
- other props - Answers :- BCC Structure
- Normally less than 0.2% C
- Cr contents (16 - 20%)
- Non-Hardenable (cannot form martensite through heat treating)
- Poor Weldability and Notch Sensitivity
- Magnetic (Ferrite)
- Excellent Corrosion Resistance in Seawater
- Not very susceptible to stress corrosion cracking
Applications of Ferritic Steels - Answers :- Atmospheric Corrosion
- Elevated Temperatures
- Decorative Applications
Notch Sensitivity - Answers :The extent to which the sensitivity of a material to fracture
is increased by the presence of a surface inhomogeneity such as a notch, a sudden
change in section, a crack, or a scratch
What does adding more Cr and N do to the ternary diagram? - Answers :Expands the
gamma loop
,*Martensitic Steels*
- structure
- carbon contents
- chromium contents
- hardenable
- weldability and notch sensitivity
- magnetic?
- other props - Answers :- BCT Structure
- High Carbon (up to 1.2%)
- Cr content (12 - 18%)
- Hardenable
- Poor Weldability and Notch Sensitivity
- Magnetic
- Cr Carbides (Holds Edges)
- Will have a phase change (Martensitic Stucture)
- use oil or air quench and its considered non equilibrium cooling
- high carbon content used to further expand gamma loop so it will transform to
Austenite, making quench hardening possible
- Large Cr Contents allow this steel to reach 100% martensite with as low as 0.7% C
during hardenability
Applications of Martensitic Steels - Answers :- Structural Components
- Tooling Applications
- Cutting and Surgical Devices
*Austenitic Steels*
- structure
- magnetic?
- carbon contents
- chromium contents
- Nickel Contents
- hardenable
- weldability and notch sensitivity
- other props - Answers :- FCC
- Non-Magnetic
- Very low C
- Cr typically 16-26%
- Nickel 8-24%
- Non-Hardenable
- Weldable
- Harden through cold working
,Alloying Elements: Fe, Cr, C, Ni
(Austenizer) (Change on X-axis)
Applications of Austenitic Steels - Answers :- Chemical Processing
- Tanks
- Piping
- Welding Structures
18/0 Ferritic
18/18 Austenitic
18/10 - Answers :18% Cr, 0% Ni
18% Cr, 18% Ni
18% Cr, 10% Ni
Chromium Iron - Answers :- hard sharp edged
- used in cutting applications
- hard to resharpen
3XX - Answers :Austenitic Steels
4XX - Answers :Either Martensitic or Ferritic
Suffixes (A, B, C) most carbon to least carbon (order of hardness) - Answers :C, B, A
F and S - Answers :Improves machinability
#'s of Ferritic Steels - Answers :430, 430F, and 446
430 - Answers :Basic type, Cr 17%
- For rust resistant on decorative and nonfunctional parts
430F - Answers :S added to improve machinability
446 - Answers :Cr much higher for improved scaling resistance
#'s of Martensitic Steels - Answers :403, 410, 416, 420, 440C
403 - Answers :Cr 12% adjusted for special physicals
410 - Answers :basic type, Cr 12%
416 - Answers :S added for machinability
- used for jigs, fixtures, and base plates
, 420 - Answers :C higher for cutting purposes
- used for tools that don't need wear resistance
440C - Answers :C higher for cutting purposes (wear resistance)
- used for cutting devices, devices, punches, dies
#'s of Austenitic Steels - Answers :302, 303, 304, 304 L, 316, 316 L
302 - Answers :Basic type, Cr 18% Ni 8%
303 - Answers :S added for machinability
- dont want to weld this (S)
- used for fasteners and and shafts
304 - Answers :C lower to avoid carbide precipitation
- lower carbon content to improve weldability
- used for chemical immersion
304L - Answers :C lower for welding application
- even lower carbon content
- used for chemical immersion
316 - Answers :Mo added for corrosion resistance
- used for chemical immersion
316L - Answers :Mo added and less C for welding applications
- used for chemical immersion
Density of Stainless Steels - Answers :about the same as carbon steels
Structure of Stainless Steels - Answers :Ferritic = Magnetic
Austenitic = Non-Magnetic
Martensitic = Magnetic
Conductivity and Electrical Resistivity of Stainless Steels - Answers :Poor conductors
Thermal Conductivity = less than 1/2 that of carbon steels
