MMET 207 LAB FINAL EXAM
QUESTIONS AND ANSWERS ALL
CORRECT
What are the temperatures and time for pack carburizing? - Answer- 1650 degrees F for
8 hours
What is the grain size after pack carburizing? - Answer- large, and it must be refined
What is the two step heat treating process to refine grains? - Answer- first, you heat to
1650 for 30 minutes for small grains in the core and then to 1400 for 20 minutes for
small grains in the case
What kind of stainless steel was tested during the cold working lab? - Answer-
Austenitic stainless steel
What is the crystal structure of austenitic stainless steel? - Answer- FCC
As thickness of austenitic stainless steel was reduced, what happened to the hardness
and magnetism? - Answer- they both increased
What are the order of the grit stages on the sandpaper used for etching? - Answer- 240,
320, 400, and 600
What were the steels that were used during heat treating? - Answer- 1018, 4340, and
52100
What were the three quench methods that were used in heat treating? - Answer- water,
air, oil
What cooling method results in the hardest material? - Answer- water quench
What cooling method results in the least hard material? - Answer- air quench
How do tempering temperatures affect the material's hardness? - Answer- increases
ductility, decreases tensile strength, increases impact strength and decreases hardness
, Heating and cooling cycle for hardening - Answer- 1650-1700 degrees F for 1hr/in of
thickness; quench
Heating and Cooling cycle for tempering - Answer- 800-1000 degrees F for 2 hours; air
cool
What is the reason for hardness testing? - Answer- to measure a metal's resistance to
indentation
What are the three methods of hardness testing? - Answer- Rockwell, Brinell, and
Vickers
What is the minor load for the regular scale? - Answer- 10 kg
What is the minor load for the superficial scale? - Answer- 3 kg
What are the major loads for regular scale Rockwell? - Answer- 60 kg, 100 kg, and
150kg
What are the major loads for superficial scale Rockwell? - Answer- 15 kg, 30 kg, and 45
kg
What are the two types of indentors? - Answer- diamond cone (brale) or hardened steel
ball
What is the notation for Rockwell A? - Answer- HRA
When is the minor load applied in hardness testing? - Answer- while zeroing the scale
What composes an HRA reading? - Answer- diamond indentor, 60 kg major load
What composes an HRC reading? - Answer- 150 kg major load, diamond indentor
What Rockwell scales use the superficial scale? - Answer- N and T
What are the steps to tensile testing? - Answer- 1. place machined specimen in tensile
tester
2. apply tensile load, increasing until sample breaks
3. during loading, at intervals measure tensile load and length
4. after the sample breaks, but the broken ends together and measure length
How is stress calculated? - Answer- force/area
How is strain calculated? - Answer- (final length-original length)/ original length
QUESTIONS AND ANSWERS ALL
CORRECT
What are the temperatures and time for pack carburizing? - Answer- 1650 degrees F for
8 hours
What is the grain size after pack carburizing? - Answer- large, and it must be refined
What is the two step heat treating process to refine grains? - Answer- first, you heat to
1650 for 30 minutes for small grains in the core and then to 1400 for 20 minutes for
small grains in the case
What kind of stainless steel was tested during the cold working lab? - Answer-
Austenitic stainless steel
What is the crystal structure of austenitic stainless steel? - Answer- FCC
As thickness of austenitic stainless steel was reduced, what happened to the hardness
and magnetism? - Answer- they both increased
What are the order of the grit stages on the sandpaper used for etching? - Answer- 240,
320, 400, and 600
What were the steels that were used during heat treating? - Answer- 1018, 4340, and
52100
What were the three quench methods that were used in heat treating? - Answer- water,
air, oil
What cooling method results in the hardest material? - Answer- water quench
What cooling method results in the least hard material? - Answer- air quench
How do tempering temperatures affect the material's hardness? - Answer- increases
ductility, decreases tensile strength, increases impact strength and decreases hardness
, Heating and cooling cycle for hardening - Answer- 1650-1700 degrees F for 1hr/in of
thickness; quench
Heating and Cooling cycle for tempering - Answer- 800-1000 degrees F for 2 hours; air
cool
What is the reason for hardness testing? - Answer- to measure a metal's resistance to
indentation
What are the three methods of hardness testing? - Answer- Rockwell, Brinell, and
Vickers
What is the minor load for the regular scale? - Answer- 10 kg
What is the minor load for the superficial scale? - Answer- 3 kg
What are the major loads for regular scale Rockwell? - Answer- 60 kg, 100 kg, and
150kg
What are the major loads for superficial scale Rockwell? - Answer- 15 kg, 30 kg, and 45
kg
What are the two types of indentors? - Answer- diamond cone (brale) or hardened steel
ball
What is the notation for Rockwell A? - Answer- HRA
When is the minor load applied in hardness testing? - Answer- while zeroing the scale
What composes an HRA reading? - Answer- diamond indentor, 60 kg major load
What composes an HRC reading? - Answer- 150 kg major load, diamond indentor
What Rockwell scales use the superficial scale? - Answer- N and T
What are the steps to tensile testing? - Answer- 1. place machined specimen in tensile
tester
2. apply tensile load, increasing until sample breaks
3. during loading, at intervals measure tensile load and length
4. after the sample breaks, but the broken ends together and measure length
How is stress calculated? - Answer- force/area
How is strain calculated? - Answer- (final length-original length)/ original length
