PURPOSE: To improve the mass effect of a titled cast iron and to prevent the deterioration of the mechanical properties thereof by increasing the content of Mo and Mn and prolonging the time for holding the cast iron at the bainitization temp.
CONSTITUTION: The spheroidal graphite cast iron is held at the austenitization temp. and is then quickly cooled in a process for producing the bainite-base spheroidal graphite cast iron contg. either one or both of Mo and Mn and contg. 0.2W1.0wt% in total. The time held for the bainitization temp. is made 2W4 times the holding time when the Mo and Mn is below the above-mentioned content. The inside of even the thick walled casting is thereby made bainite and therefore the mass effect (hardenability) is improved and segregation is decreased. The machineability is eventually improved and the improvement of the elongation and tensile strength is made possible.
TOMITA TAKETOSHI
INADA MITSURU
| JPS5842721A | 1983-03-12 |