MMET 207 LAB FINAL QUESTIONS AND ANSWERS
What is the reason for hardness testing? - Answers :to measure a metal's resistance to
indentation
What are the three methods of hardness testing? - Answers :Rockwell, Brinell, and
Vickers
What is the minor load for the regular scale? - Answers :10 kg
What is the minor load for the superficial scale? - Answers :3 kg
What Rockwell scales use the superficial scale? - Answers :N and T
What are the steps to tensile testing? - Answers :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? - Answers :force/area
How is strain calculated? - Answers :(final length-original length)/ original length
What is the modulus of elasticity? - Answers :stress/strain in the straight line portion of
graph; can't calculate when the graph isn't straight
What is percent elongation? - Answers :final strain *100%
What is the proportional limit? - Answers :when the behavior is elastic but not
proportional
What is the yield strength? - Answers :when the material begins plastic deformation
What is the tensile strength or UTS of a material? - Answers :the highest strength
achievable
What is the breaking strength? - Answers :the strength when the material breaks
What is ductility? - Answers :stretch, related to percent elongation
Modulus of elasticity measures what? - Answers :stiffness of a material
How do you find the 0.2% offset? - Answers :go to 0.2 on the strain axis (X) and draw a
line that's parallel to the modulus of elasticity
, What was the type of impact test used? - Answers :Charpy V notch
What was the impact testing machine set to before each test? - Answers :maximum
value
What is the value that is shown after a specimen is broken during an impact test? -
Answers :the absorbed energy in ft.lbs
What was the basic concept behind the impact testing lab? - Answers :to test the impact
strength of samples at different temperature and plot them on a graph
When plotting the graph for ductile to brittle transition temperature, what should the axis'
be labeled? - Answers :temperature on x, impact strength on y
What is ductile to brittle transition temperature? - Answers :the temperature at which the
fracture energy passes below a predetermined value
What are the major loads for regular scale Rockwell? - Answers :60 kg, 100 kg, and
150kg
What are the major loads for superficial scale Rockwell? - Answers :15 kg, 30 kg, and
45 kg
What are the two types of indentors? - Answers :diamond cone (brale) or hardened
steel ball
What is the notation for Rockwell A? - Answers :HRA
When is the minor load applied in hardness testing? - Answers :while zeroing the scale
What composes an HRA reading? - Answers :diamond indentor, 60 kg major load
What composes an HRC reading? - Answers :150 kg major load, diamond indentor
What type of materials have ductile to brittle transition temperatures? - Answers :BCC
materials
A 36 - Answers :ferrite and pearlite
Gray Cast Iron (GCI) - Answers :ferrite, pearlite and graphite flakes
1095 Water Quenched and Tempered - Answers :martensite, ferrite and cementite
4340 A - Answers :ferrite and pearlite
Ductile Cast Iron - Answers :ferrite, pearlite and graphite spheroids
What is the reason for hardness testing? - Answers :to measure a metal's resistance to
indentation
What are the three methods of hardness testing? - Answers :Rockwell, Brinell, and
Vickers
What is the minor load for the regular scale? - Answers :10 kg
What is the minor load for the superficial scale? - Answers :3 kg
What Rockwell scales use the superficial scale? - Answers :N and T
What are the steps to tensile testing? - Answers :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? - Answers :force/area
How is strain calculated? - Answers :(final length-original length)/ original length
What is the modulus of elasticity? - Answers :stress/strain in the straight line portion of
graph; can't calculate when the graph isn't straight
What is percent elongation? - Answers :final strain *100%
What is the proportional limit? - Answers :when the behavior is elastic but not
proportional
What is the yield strength? - Answers :when the material begins plastic deformation
What is the tensile strength or UTS of a material? - Answers :the highest strength
achievable
What is the breaking strength? - Answers :the strength when the material breaks
What is ductility? - Answers :stretch, related to percent elongation
Modulus of elasticity measures what? - Answers :stiffness of a material
How do you find the 0.2% offset? - Answers :go to 0.2 on the strain axis (X) and draw a
line that's parallel to the modulus of elasticity
, What was the type of impact test used? - Answers :Charpy V notch
What was the impact testing machine set to before each test? - Answers :maximum
value
What is the value that is shown after a specimen is broken during an impact test? -
Answers :the absorbed energy in ft.lbs
What was the basic concept behind the impact testing lab? - Answers :to test the impact
strength of samples at different temperature and plot them on a graph
When plotting the graph for ductile to brittle transition temperature, what should the axis'
be labeled? - Answers :temperature on x, impact strength on y
What is ductile to brittle transition temperature? - Answers :the temperature at which the
fracture energy passes below a predetermined value
What are the major loads for regular scale Rockwell? - Answers :60 kg, 100 kg, and
150kg
What are the major loads for superficial scale Rockwell? - Answers :15 kg, 30 kg, and
45 kg
What are the two types of indentors? - Answers :diamond cone (brale) or hardened
steel ball
What is the notation for Rockwell A? - Answers :HRA
When is the minor load applied in hardness testing? - Answers :while zeroing the scale
What composes an HRA reading? - Answers :diamond indentor, 60 kg major load
What composes an HRC reading? - Answers :150 kg major load, diamond indentor
What type of materials have ductile to brittle transition temperatures? - Answers :BCC
materials
A 36 - Answers :ferrite and pearlite
Gray Cast Iron (GCI) - Answers :ferrite, pearlite and graphite flakes
1095 Water Quenched and Tempered - Answers :martensite, ferrite and cementite
4340 A - Answers :ferrite and pearlite
Ductile Cast Iron - Answers :ferrite, pearlite and graphite spheroids
