Method for manufacturing high strength component, and high strength component

TLDR: In this paper, a steel plate containing a composition consisting of, by mass, 0.1 to 0.55% C, 1 to 3% Mn, ≤ 1% Si, ≤ 0.03% S, ≤0.1% P, and ≤ 1.01% N and the balance Fe with inevitable impurities is heated up to a temperature of from the Ac3 point to the melting point.

Abstract: PROBLEM TO BE SOLVED: To provide a method for manufacturing a high strength component which has a strength of over 1200 MPa after forming by high temperature and is excellent in a hydrogen embrittlement resistance, and further to provide the high strength component. SOLUTION: The method for manufacturing the high strength component is carried out as follows. A steel plate containing a composition consisting of, by mass, 0.1 to 0.55% C, 0.1 to 3% Mn, ≤1% Si, ≤0.03% S, ≤0.1% P and ≤0.01% N and the balance Fe with inevitable impurities is heated up to a temperature of from the Ac3 point to the melting point. After that, the forming work is started at a temperature higher than the transformation temperatures for ferrite, pearlite, bainite, and martensite structure. After the forming work, the component is quenched by cooling it in a die to produce the high strength component. In a process that shearing work is carried out, when the heating atmosphere has the hydrogen content of ≤6% and the dew point of ≤15°C, the ratio of the length of the broken-out section of the cut surface to the thickness is ≤80%, and the ratio of the shear droop to the thickness is ≤7.0%. COPYRIGHT: (C)2009,JPO&INPIT