Which factors increase hardenability?

Q.  Which of the following factors increases hardenability of a metal?
- Published on 11 Sep 15

a. Alloying elements
b. Fine grain size
c. Very high carbon content in steel
d. All of the above

ANSWER: Alloying elements


  • Sravanthi    -Posted on 12 Nov 15
    Different factors affecting hardenability are as follows:

    1) Alloying elements: Hardenability increases due to presence of alloying elements in steel. Carbon, manganese, chromium, silicon, nickel, vanadium, etc are the different alloying elements used in steel.

    2) Austenitic grain size: Fine grain size reduces hardenability because they have large density of heterogeneous nucleation sites.

    - As grain size decreases hardness, yield strength, tensile strength, fatigue strength, etc increases. Fine grain steels have greater fatigue resistance.

    - Grain size can be determined by an optical microscope on a transverse metallographic mount by counting grains in a specific area.

    3) Very high carbon content in steel: High carbon content in steel decreases hardenability. Carbon in steel generally increases hardenability upto 0.65% but if used in high quantity it reduces toughness and increases brittleness.

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