MANUFACTURING METHOD OF HIGH-STRENGTH, HIGH-TOUGHNESS FERRITE/PEARLITE NON-HEAT-TREATED STEEL FORGING PART

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method of a ferrite and pearlite non-heat-treated steel forging part, capable of easily realizing a fine ferrite and pearlite structure through freezing and hardening of crystal grains, by using a ferrite and pearlite non-heat-treated steel containing V and suppressing process heat immediately after forging.;SOLUTION: In the manufacturing method of the high-strength, high-toughness ferrite and pearlite non-heat-treated steel forging part, the ferrite and pearlite non-heat-treated steel containing by mass, 0.05-0.50% V and comprising ≥90% of ferrite and pearlite structure is heated to a solution temperature of a V carbide, subsequently cooled to 700-950°C, subjected to forging at this temperature range so that the compression forming rate reaches ≥30% and the contact time with a die reaches ≥0.20 sec, and subsequently cooled so as to induce ferrite and pearlite transformation to obtain the forging part having a pearlite grain size of ≤18 μm.;COPYRIGHT: (C)2009,JPO&INPIT