MMET 207 Exam 2 Actual study set with
Questions and correct/verified Answers
Cold Work - ANSWER-O, W, A, D
O series - ANSWER-Oil Hardening
O1, O2, O6, O7
W series - ANSWER-Water Hardening
W1, W2, W5
A series - ANSWER-Medium Alloy Air Hardening
A2, A4, A6, A8, A9, A10, A11
D series - ANSWER-High Carbon, High Chromium
D2, D3, D4, D5, D7
Shock Resisting - ANSWER-S series
S1, S2, S4, S5, S6, S7
Hot Work - ANSWER-H, P
H Series - ANSWER-H10-H19 Chromium Types
H20-H39 Tungsten Types
H40-H59 Molybdenum Types
P series - ANSWER-Molded
P6, P20, P21
High Speed - ANSWER-M, T
M series - ANSWER-Molybdenum Types
M1, M2, M3-1, M3-2, M4, M6, M7, M10, M33, M36, M41, M46, M50
T series - ANSWER-Tungsten Types
T1, T4, T5, T6, T8, T15
Special Purpose - ANSWER-L series
L2, L6
Carbon steel Hardening Properties - ANSWER-Hardenability: Biggest back curve/worst hardenability
Hardness: Sharp drop as Temper Temp Increases
Abrasion Resistance: Wear volume grows the most over time
Alloy Steel Hardening Properties - ANSWER-Hardenability: Middle Largest Back curve/middle
hardenability
Hardness: Slow decline
Abrasion Resistance: Medium wear volume amount
Tool Steels - ANSWER-Hardenability: Smallest Back curve/best hardenability
Hardness: Goes down a little, then back up, then sharp drop
Abrasion Resistance: Least amount of wear volume
,Safety in Hardening - ANSWER-Risk of Damaging from hardneing (quench cracks)
Eutectic Structures - ANSWER-spread out carbide structures
Eutectic Networks - ANSWER-Long multiple chains of carbide structures
Severe Banding - ANSWER-One long carbide chain structure
Why are eutectic things made? - ANSWER-Caused by lack of hot work or problems in processing or
alloying
Makes the tool steel crack easier
Hardening Characteristics - ANSWER-Safety in Hardening
Depth of Hardening
Size change in hardening
Resistance to decarburization
Depth of Hardening - ANSWER-through hardening, Hardenability
Size change in hardening - ANSWER-Very important for design
Resistance to decarburization - ANSWER-Scale oxidation of surface during heat treatment
Use Characteristics - ANSWER-Resistance to heat softening
Wear Resistance
Toughness
Machinability
Resistance to heat softening - ANSWER-If enough heat is generated during operations that could cause
tempering, softening of tool steels
Wear resistance - ANSWER-Difficult to quantify, dependent upon scientific application or wear criteria
Toughness - ANSWER-All tool steels have little or no toughness, some are just worse than others
Machinability - ANSWER-Difficult to quantify, very subjective
Body centered Tretraganol - ANSWER-BCT
Elongated compared to BCC
BCC has low carbon content, BCT has carbon stuck in it because of rapid cooling
Martensite is this
Acicular - ANSWER-needle like structures
BCT 100% Martensite
Martensite has: - ANSWER-High tensile & high hardness
lowest ductility & lowest impact strength
Heat treatments - ANSWER-Tempering
Stress Relieving
Spheroidizing
Austempering
Martempering
Normalizing
,Annealing
Hardening
Tempering - ANSWER-After hardening process
Gains more impact strength/ductility & lose less tensile strength/hardness (trade off is much less)
800-1000 F; air cool
Stress relieving - ANSWER-used alot throughout industry
residual stress: stress leftover from a process (ex: cold working); Aims to get rid of this
900-1250 F
1 hr/inch of thickness; air cool
Spheroidizing - ANSWER-Improves machinablitiy & resistance to fracture
used if we tempered much to long
1200 F; 96+ hrs
Raise to temp right before austenite transition temp and then hold it there for very long
releases carbon from BCT, change to BCC ferrite + cementite spheroids
Makes "spheroidized Martensite"
-No actual martensite in it; composed of BCC ferrite + cementite spheroids
Austempering - ANSWER-Stops quench cracks & hardens material
cool in two steps
-first cool in molten salt (high liquid temp)
-then cool in water
Makes bainite
-looks like very tempered martensite(very hard)
Martempering - ANSWER-2 stages of cooling
-Molten salt bath with lower temp than austempering
-cool in water
Makes untempered martensite
*in order to get martensite, Austenite must be made first*
Flame hardening system - ANSWER-Martensite on just the surface
Selective hardening- works best with medium carbon steel
martensite on outside, ferrite & pearlite on inside
Difusion - ANSWER-Change chemistry of surface while solid
low carbon and low alloy steels
Must have this to occur:
*-difference in concentration*
*-material with low carbon*
Carburizing - ANSWER-Pack metal in carbon or carbon based gas and heat it up so that the metal soaks
up carbon
, two types:
-pack
-gas
Nitriding - ANSWER--Just like carburizing, but use nitrogen instead
dont go nearly as hot (nitrogen can get in without steel being FCC(can stay BCC))
Nitrides end up on surface (very hard & unwearable)
Dont need to temper
Brittle white layer that must be removed after nitriding process
takes longer than carburizing
thickness is smaller than carburizing
no grain growth in nitriding, only in carburizing
Manganese (identification) - ANSWER-13xx
15xx
Nickel (identification) - ANSWER-23xx
25xx
Nickel-Chromium (identification) - ANSWER-31xx
33xx
Molybdenum (identification) - ANSWER-40xx
41xx Chromium & Molybdenum
43xx Nickel & Chromium
46xx
48xx
Chromium (Identification) - ANSWER-51xx
52xx Chromium
Chromium-vanadium (identification) - ANSWER-61xx
Multiple Alloy (identification) - ANSWER-86xx, 87xx, 92xx, 93xx, 94xx, 94Bxx
Carbon Steel - ANSWER-SAE 1006-1095 General Purpose
SAE 1108-1151 Free Machining
SAE 1513-1572 High Manganese
A611, A619, A620 ASTM Grades
Aluminum - ANSWER-Aids nitriding
Restricts Grain Growth
Removes oxygen in steel melting
Sulfur and Phosphorus - ANSWER-Adds Machinability
Reduces Weldability, ductility, & toughness
Increases resistance to corrosion & oxidation
Chromium - ANSWER-Increases hardenability (big effect)
Questions and correct/verified Answers
Cold Work - ANSWER-O, W, A, D
O series - ANSWER-Oil Hardening
O1, O2, O6, O7
W series - ANSWER-Water Hardening
W1, W2, W5
A series - ANSWER-Medium Alloy Air Hardening
A2, A4, A6, A8, A9, A10, A11
D series - ANSWER-High Carbon, High Chromium
D2, D3, D4, D5, D7
Shock Resisting - ANSWER-S series
S1, S2, S4, S5, S6, S7
Hot Work - ANSWER-H, P
H Series - ANSWER-H10-H19 Chromium Types
H20-H39 Tungsten Types
H40-H59 Molybdenum Types
P series - ANSWER-Molded
P6, P20, P21
High Speed - ANSWER-M, T
M series - ANSWER-Molybdenum Types
M1, M2, M3-1, M3-2, M4, M6, M7, M10, M33, M36, M41, M46, M50
T series - ANSWER-Tungsten Types
T1, T4, T5, T6, T8, T15
Special Purpose - ANSWER-L series
L2, L6
Carbon steel Hardening Properties - ANSWER-Hardenability: Biggest back curve/worst hardenability
Hardness: Sharp drop as Temper Temp Increases
Abrasion Resistance: Wear volume grows the most over time
Alloy Steel Hardening Properties - ANSWER-Hardenability: Middle Largest Back curve/middle
hardenability
Hardness: Slow decline
Abrasion Resistance: Medium wear volume amount
Tool Steels - ANSWER-Hardenability: Smallest Back curve/best hardenability
Hardness: Goes down a little, then back up, then sharp drop
Abrasion Resistance: Least amount of wear volume
,Safety in Hardening - ANSWER-Risk of Damaging from hardneing (quench cracks)
Eutectic Structures - ANSWER-spread out carbide structures
Eutectic Networks - ANSWER-Long multiple chains of carbide structures
Severe Banding - ANSWER-One long carbide chain structure
Why are eutectic things made? - ANSWER-Caused by lack of hot work or problems in processing or
alloying
Makes the tool steel crack easier
Hardening Characteristics - ANSWER-Safety in Hardening
Depth of Hardening
Size change in hardening
Resistance to decarburization
Depth of Hardening - ANSWER-through hardening, Hardenability
Size change in hardening - ANSWER-Very important for design
Resistance to decarburization - ANSWER-Scale oxidation of surface during heat treatment
Use Characteristics - ANSWER-Resistance to heat softening
Wear Resistance
Toughness
Machinability
Resistance to heat softening - ANSWER-If enough heat is generated during operations that could cause
tempering, softening of tool steels
Wear resistance - ANSWER-Difficult to quantify, dependent upon scientific application or wear criteria
Toughness - ANSWER-All tool steels have little or no toughness, some are just worse than others
Machinability - ANSWER-Difficult to quantify, very subjective
Body centered Tretraganol - ANSWER-BCT
Elongated compared to BCC
BCC has low carbon content, BCT has carbon stuck in it because of rapid cooling
Martensite is this
Acicular - ANSWER-needle like structures
BCT 100% Martensite
Martensite has: - ANSWER-High tensile & high hardness
lowest ductility & lowest impact strength
Heat treatments - ANSWER-Tempering
Stress Relieving
Spheroidizing
Austempering
Martempering
Normalizing
,Annealing
Hardening
Tempering - ANSWER-After hardening process
Gains more impact strength/ductility & lose less tensile strength/hardness (trade off is much less)
800-1000 F; air cool
Stress relieving - ANSWER-used alot throughout industry
residual stress: stress leftover from a process (ex: cold working); Aims to get rid of this
900-1250 F
1 hr/inch of thickness; air cool
Spheroidizing - ANSWER-Improves machinablitiy & resistance to fracture
used if we tempered much to long
1200 F; 96+ hrs
Raise to temp right before austenite transition temp and then hold it there for very long
releases carbon from BCT, change to BCC ferrite + cementite spheroids
Makes "spheroidized Martensite"
-No actual martensite in it; composed of BCC ferrite + cementite spheroids
Austempering - ANSWER-Stops quench cracks & hardens material
cool in two steps
-first cool in molten salt (high liquid temp)
-then cool in water
Makes bainite
-looks like very tempered martensite(very hard)
Martempering - ANSWER-2 stages of cooling
-Molten salt bath with lower temp than austempering
-cool in water
Makes untempered martensite
*in order to get martensite, Austenite must be made first*
Flame hardening system - ANSWER-Martensite on just the surface
Selective hardening- works best with medium carbon steel
martensite on outside, ferrite & pearlite on inside
Difusion - ANSWER-Change chemistry of surface while solid
low carbon and low alloy steels
Must have this to occur:
*-difference in concentration*
*-material with low carbon*
Carburizing - ANSWER-Pack metal in carbon or carbon based gas and heat it up so that the metal soaks
up carbon
, two types:
-pack
-gas
Nitriding - ANSWER--Just like carburizing, but use nitrogen instead
dont go nearly as hot (nitrogen can get in without steel being FCC(can stay BCC))
Nitrides end up on surface (very hard & unwearable)
Dont need to temper
Brittle white layer that must be removed after nitriding process
takes longer than carburizing
thickness is smaller than carburizing
no grain growth in nitriding, only in carburizing
Manganese (identification) - ANSWER-13xx
15xx
Nickel (identification) - ANSWER-23xx
25xx
Nickel-Chromium (identification) - ANSWER-31xx
33xx
Molybdenum (identification) - ANSWER-40xx
41xx Chromium & Molybdenum
43xx Nickel & Chromium
46xx
48xx
Chromium (Identification) - ANSWER-51xx
52xx Chromium
Chromium-vanadium (identification) - ANSWER-61xx
Multiple Alloy (identification) - ANSWER-86xx, 87xx, 92xx, 93xx, 94xx, 94Bxx
Carbon Steel - ANSWER-SAE 1006-1095 General Purpose
SAE 1108-1151 Free Machining
SAE 1513-1572 High Manganese
A611, A619, A620 ASTM Grades
Aluminum - ANSWER-Aids nitriding
Restricts Grain Growth
Removes oxygen in steel melting
Sulfur and Phosphorus - ANSWER-Adds Machinability
Reduces Weldability, ductility, & toughness
Increases resistance to corrosion & oxidation
Chromium - ANSWER-Increases hardenability (big effect)
