10) A punch is made out of alloyed steel. After hardening it, a crack takes place. What can be the reason to develop this crack ?
The punch is heated too little
Related Heat Treatment MCQ - Machinist(Set-1) with Answers
To produce certain desired properties
Parts to be hardened by case hardening process are made from a steel with a carbon content of 0.15% so that they will not respond to direct hardening.
The steel is subjected to treatment in which the carbon content of the surface layer is increased to about 0.9%.
When the carburised steel is heated and quenched, only the surface layer will respond, and the core will remain soft and tough as required.