| 摘要 |
<p>PURPOSE:To obtain a structural member having sufficient strength and superior wear resistance at the surface layer part and high toughness at the central part by carburizing a structural member and carrying out a high frequency heat treatment. CONSTITUTION:When a structural member such as a shank rod for a rock drill is heat treated to harden the surface, the member is first carburized, and hardened after carburization, or tempered, after carburization and hardening, then a high frequency heat treatment is carried out. The treated member may be further tempered. The central part of the structural member is made of low carbon martensite and has high toughness. The surface layer part has sufficient hardness, and the grains are made fine.</p> |
