PRODUCTION OF STEEL MATERIAL WITH HIGH ATMOSPHERE CORROSION RESISTANCE FOR STEEL FRAME STRUCTURE EXCELLENT IN HIGH TEMPERATURE STRENGTH CHARACTERISTIC

摘要

PURPOSE: To produce a steel material for steel frame structure excellent in weldability and atmosphere corrosion resistance as well as in strength at high temp. ;CONSTITUTION: A steel having a composition which consists of 0.03-0.15% C, 0.05-0.90% Si, 0.30-2.00% Mn, 0.01-0.10% P, 0.05-0.60% Mo, 0.1-2.0% Cr, 0.1-0.5% Ni, 0.1-1.0% Cu, 0.005-0.1% sol.Al, and the balance Fe with inevitable impurities and in which Mo* represented by the undermentioned equation 1 and PCM represented by the undermentioned equation 2 are regulated to ≥0.4 and ≤0.25, respectively, is used as a stock and this stock is heated at 1000-1250°C and rolled at ≥30% at a temp. in the recrystallization temp. region to undergo the regulation of the structure in the surface layer into the structure in which bainite comprises ≥80% by area ratio: Mo* (%)=Mo+1.5C+(0.8+3Mo)V +(2+5Mo)Nb...1; PCM(%)+C+(Si/30)+(Mn/20)+(Cu/20)+(Ni/60)+(Cr/20)+(Mo/15)+(V/10)+5B...2. In the above equations, the atomic symbols represent their contents (wt.%), respectively.;COPYRIGHT: (C)1993,JPO&Japio