148) which of the following is a case hardening process?

149) The process of inducing carbon to ______ Carbon steels in order to give it a hard surface is known as carburizing.

150) The process in which carbon and nitrogen both are absorbed by the metal surface to get it hardened is known as

151) quenching is not necessary when hardening is done by

152) which of the following generally decreases in the steel after quench hardening?