| 摘要 |
PURPOSE:To shorten the treating time required in the spheroidizing treatment of carbide in preparing rod steel and a wire material to a large extent, by re- raising a steel temp. by the processing heat generated during hot processing while applying controlled cooling to the heated steel or holding the same to a constant temp. after rolling. CONSTITUTION:Steel capable of containing alloying elements such as Si, Mn or the like and containing 2% or less of C is heated to an Ac1 temp. or more and thereafter subjected to hot rolling for adding deformation. In this case, this steel is cooled to a temp. region ranging from the Ac1 temp. or less to -200 deg.C or more prior to finish rolling and succeedingly subjected to plastic deformation of 10% or more by finish rolling to permit the same to reach a temp. region of the Ac3 temp. or less -Ac1-100 deg.C or more by the deformation heat. After deformation destruction is generated to carbide by this treatment, the steel is cooled at a cooling speed of 100 deg.C/min or less in a temp. region ranging from the deformation temp. to 500 deg.C to obtain a spheroidal structure. As a result, a spheroidizing annealing treatment time is shortened to a large extent and rod steel and a wire material each having a spheroidal structure is obtained. |
