| 摘要 |
PURPOSE:To obtain uniformly dispersed annealing structure by performing heating to above hot working or austenitizing temp. then decomposing treatment of residual austenite followed by spheriodizing annealing. CONSTITUTION:After heating to hot working or austenitizing temp., cooling down to the temp. at which martensite transformation takes place is performed, thence decomposition treatment of residual austenite such as heating to above the temp. at which residual austenite decomposes or cooling down to below ordinary temp. is carried out, following to which spheriodizing annealing is performed. Thereby, the deposition of chainlike carbide is prevented and the uniformly fine carbide structure is formed. |
