一、引言全世界每年生产5亿多吨各种金属,其中钢铁约占95%,而铝、铜、钛、镍等其它金属总共只占5%左右.因而,在可以预见的将来,钢和铁作为结构材料仍将保持其主导地位.高强度低合金钢(国内称作普通低合金钢),是近十几年来发展很快的钢类.其基本化学成分大多为:0.1～0.3%C;0.6～1.7%Mn;Cr、Mo、Cu、Si、Ni、 I. INTRODUCTION More than 500 million tons of various metals are produced each year in the world, of which steel accounts for about 95%, while other metals such as aluminum, copper, titanium and nickel make up only about 5% of the total. Therefore, for the foreseeable future, Iron as the structural material will still maintain its dominance.High-strength low-alloy steel (commonly known as domestic low-alloy steel), is developed rapidly over the past decade the steel.Its basic chemical composition mostly: 0.1 ~ 0.3% C ; 0.6-1.7% Mn; Cr, Mo, Cu, Si, Ni,