800 MPa级高强钢焊缝金属热处理组织与性能

在10Ni5CrMoV高强结构钢焊接中,为了获得良好的强韧性匹配,焊后需要进行热处理来改善焊缝金属的组织和性能.试验采用富氩气体保护焊焊接10Ni5CrMoV钢,分析了不同调质热处理工艺下焊缝组织、性能的变化规律.结果表明,焊缝金属焊态的组织主要是贝氏体、少量马氏体和残余奥氏体组织,调质热处理后焊缝组织主要为回火马氏体,随着回火温度的升高,焊缝中残余奥氏体减少,马氏体中碳化物析出长大并有球化趋势.调质态焊缝金属的强度随着回火温度的升高而逐渐降低,而韧性随着回火温度的升高而显著提高.

Microstructure and property of PWHT weld metal of 800MPa grade low alloy steel

In order to achieve good toughness and strength in welding 10Ni5CrMoV steel, heat treatment is usually carried out to improve the mechanical properties of the weld metal. 10Ni5CrMoV steel was welded with rich Ar shielding gas, and the microstructure and mechanical properties of the weld metal were investigated after different heat treatment. The results indicate that the microstructures of the weld metal are bainite, martensite and a small amount of retained austenite. After quenching and tempering, the microstructure of the weld metal is tempered martensite. The amount of retained austenite in the weld metal decreases and the size of carbide in the martensite increases with tempered temperature increasing. The strength of the weld metal decreases as tempered temperature increases, and the toughness is improved when tempered temperature is increased.