Manufacturing Processes Questions and Answers – Normalizing & Tempering

«
»

This set of Manufacturing Processes Multiple Choice Questions & Answers (MCQs) focuses on “Normalizing & Tempering”.

1. In normalizing of hypoeutectoid steel, the component is heated to a temperature above _____
a) 535⁰C
b) 610⁰C
c) 800⁰C
d) 910⁰C
View Answer

Answer: d
Explanation: Normalizing process consists of three steps. The first step involves heating the steel component above the 910⁰C temperature for hypoeutectoid steels and above Acm (upper critical temperature for cementite) temperature for hypereutectoid steels by 30⁰C to 50⁰C.
advertisement

2. In normalizing, components are cooled _____
a) using water
b) using oil
c) in still air
d) in furnace
View Answer

Answer: c
Explanation: The final step in normalizing involves cooling the hot steel component to room temperature in still air. Due to air cooling, normalized components show a slightly different structure and properties than annealed components.

3. Normalizing is used for _____
a) alloy steels
b) high carbon steels
c) tool steels
d) aluminium alloys
View Answer

Answer: b
Explanation: Normalizing is used for high-carbon (hypereutectoid) steels to eliminate the cementite network that may develop upon slow cooling in the temperature range from point Acm (upper critical temperature for cementite) to point A1 (lower critical point temperature).
advertisement
advertisement

4. Normalizing is not used for relieve internal stresses by which of the following processes?
a) Casting
b) Drilling
c) Welding
d) Forming
View Answer

Answer: b
Explanation: Normalizing is also used to relieve internal stresses induced by heat treating, welding, casting, forging, forming, or machining. Normalizing also improves the ductility without reducing the hardness and strength.

5. Martensite obtained after hardening is extremely _______
a) hard
b) ductile
c) brittle
d) soft
View Answer

Answer: c
Explanation: The hardened steel is not readily suitable for engineering applications. It possesses few drawbacks, which are as follows:
• martensite obtained after hardening is extremely brittle and will result in failure of engineering components by cracking
• Formation of martensite from austenite by quenching produces high internal stresses in the hardened steel.
advertisement

6. Structures obtained after hardening consists of _______
a) martensite
b) cementite
c) perlite
d) carbon
View Answer

Answer: a
Explanation: Structures obtained after hardening consists of martensite and retained austenite. Both these phases are metastable and will change to stable phases with time which subsequently results in a change in dimensions and properties of the steel in service.

7. Tempering is achieved by heating hardened steel to a temperature in the range of ______
a) 100⁰C – 150⁰C
b) 100⁰C – 680⁰C
c) 200⁰C – 375⁰C
d) 300⁰C – 835⁰C
View Answer

Answer: b
Explanation: Tempering is achieved by heating hardened steel to a temperature below lower critical temperature, which is in the range of 100⁰C – 680⁰C, hold the component at this temperature for a soaking period of 1 to 2 hours (can be increases up to 4 hours for large sections and alloy steels), and subsequently cooling back to room temperature.
advertisement

8. Highly alloyed tool steels are tempered in the range of ______
a) 100⁰C – 190⁰C
b) 180⁰C – 300⁰C
c) 450⁰C – 620⁰C
d) 500⁰C – 600⁰C
View Answer

Answer: d
Explanation: The tempering temperature is decided based on the type of steel. Highly alloyed tool steels are tempered in the range of 500⁰C – 600⁰C. Low alloy steels are tempered above 400⁰C to get a good combination of strength and ductility. Spring steels are tempered between 300⁰C – 400⁰C.

9. Increase in the tempering temperature ______
a) increases hardness
b) increases ductility
c) decreases conductivity
d) increases toughness
View Answer

Answer: d
Explanation: It is observed that the increase in the tempering temperature decreases the hardness and internal stresses while increases the toughness. But after a particular temperature, there is no significant change in hardness and toughness.
advertisement

10. Normalizing takes less time than that for annealing.
a) True
b) False
View Answer

Answer: a
Explanation: The properties of normalized components are not much different from those of annealed components. However, normalizing takes less time and is more convenient and economical than annealing and hence is a more common heat treatment in industries.

11. Perlite formed during normalising is coarse in nature.
a) True
b) False
View Answer

Answer: b
Explanation: Pearlite formed during normalizing is fine and usually appears unresolved with an optical microscope. Whereas, pearlite during annealing is coarse and usually gets resolved by the optical microscope.

12. In normalizing, grain size distribution ______
a) is uniform
b) is less uniform
c) varies directly with temperature
d) varies with time
View Answer

Answer: b
Explanation: If we compare annealing and normalizing, the following point can be made:
In annealing,
• Grain size distribution is more uniform
• Internal stresses are least
• Less hardness, tensile strength and toughness
In normalizing,
• Grain size distribution is slightly less uniform
• Internal stresses are slightly more
• Slightly more hardness, tensile strength and toughness.

Sanfoundry Global Education & Learning Series – Manufacturing Processes.

To practice all areas of Manufacturing Processes, here is complete set of 1000+ Multiple Choice Questions and Answers.

Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

advertisement
advertisement
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter