CD CD Drafter Materials & Manufacturing Processes 1 — Questions and Answers
Question 1: Which material property describes a metal's ability to be drawn into a wire without breaking?
- Ductility (Correct answer)
- Brittleness
- Hardness
- Elasticity
Correct answer: Ductility
Ductility is the property that allows a material to be drawn into a wire or stretched without fracturing.
Question 2: On a technical drawing, a surface finish symbol with a value of 125 µin Ra indicates:
- A relatively smooth machined surface (Correct answer)
- A polished mirror surface
- A rough as-cast surface
- A ground surface
Correct answer: A relatively smooth machined surface
125 µin Ra is a standard machined surface finish commonly used for general-purpose machined parts.
Question 3: Which manufacturing process uses a rotating cutting tool to remove material from a stationary workpiece?
- Milling (Correct answer)
- Turning
- Drilling
- Grinding
Correct answer: Milling
Milling uses a rotating multi-tooth cutter to remove material while the workpiece is fed into it.
Question 4: What does the abbreviation 'HR' indicate when specified next to a material designation on a drawing?
- Hot Rolled (Correct answer)
- High Resistance
- Heat Resistant
- Hard Rolled
Correct answer: Hot Rolled
HR stands for Hot Rolled, indicating the steel was processed above its recrystallization temperature.
Question 5: A casting process that forces molten metal into a reusable steel mold under high pressure is called:
- Die casting (Correct answer)
- Sand casting
- Investment casting
- Centrifugal casting
Correct answer: Die casting
Die casting injects molten metal into permanent steel dies under high pressure, producing dimensionally accurate parts.
Question 6: Which heat treatment process hardens only the outer surface of a steel part while keeping the core tough?
- Case hardening (Correct answer)
- Annealing
- Normalizing
- Tempering
Correct answer: Case hardening
Case hardening (carburizing or nitriding) adds carbon or nitrogen to the surface layer, creating a hard exterior with a tough core.
CD CD Drafter Materials & Manufacturing Processes 1
Which material property describes a metal's ability to be drawn into a wire without breaking?