Mo元素对船用高强钢碱性焊条熔敷金属组织和性能的影响

Influence of Mo on Mechanical Properties and Microstructures of Deposited Metal of Basic Electrode for High Strength Marine Steel

测试5种不同Mo含量的船用高强钢焊条的熔敷金属力学性能,采用光学显微镜和透射电镜进行微观组织观察和分析,并采用Jamtpro软件模拟计算熔敷金属的焊接CCT图。结果表明,随着Mo含量增多,熔敷金属屈服强度和抗拉强度显著提升,但冲击韧性及塑性呈下降趋势;焊接CCT曲线逐渐向右下方移动,熔敷金属的组织由韧性较好的针状铁素体逐渐向硬脆的贝氏体和马氏体转变;当Mo含量高于0.482%时,熔敷金属中会产生对韧性不利的M-A组元,当Mo含量高于0.887%时,熔敷金属中会析出Mo的碳化物,造成严重脆化。

The mechanical properties of deposited metals of five high strength marine steel electrods with different Mo contents were tested, the microstructures were observed and analyzed by optical microscope and transmission electron microscope, and the welding CCT diagrams of deposited metals were also analog computed by Jamtpro software. The results showed that with the increasing of Mo content, the yield strength and tensile strength of deposited metal significantly enhanced, while the ductility and toughness decreased evidently; welding CCT curves moved down to the right gradually, the microstructure of the deposited metal turned from acicular ferrite of good toughness to the brittle bainite and martensite ; the M-A phase which would deteriorate deposited metal＇s toughness appeared when Mo content exceeded 0.482%, and the Mo carbide would precipitate when Mo con- tent exceeded 0. 887%. leadinz to severe embrittlement of deoosited metal.