合金元素对09MnNiDR钢焊接热影响区韧性的影响

Effect of Alloying Agent on the Heat Affected Zone Toughness of 09MnNiDR

通过对不同成分焊接试板进行力学性能测试、金相组织分析及热影响区第二相粒子透射电镜观察,研究了Ni,Ti两个关键合金元素对09MnNiDR钢热影响区韧性的影响规律,从而达到改善热影响区低温韧性的目的.结果表明：通过增加Ni含量改善热影响区韧性的效果不明显且成本较高,而通过将Ti质量分数由0.016％增加到0.021％～0.026％,可在不增加Ni含量的前提下使热影响区冲击韧性显著改善;Ti元素改善09MnNiDR钢热影响区韧性的机制是随着Ti含量增加高熔点第二相粒子的数量增加、尺寸细化、热稳定性提高,从而达到提高第二相粒子抑制热影响区晶粒长大,减小热影响区宽度的作用,进而改善热影响区韧性.

Through testing the mechanical properties of welding joint, and observing the metallurgical structure and second phase in heat affected zone （HAZ）, the influence of Ni, Ti to the impact ductility of 09MnNiDR＇s HAZ was discussed, and the impact ductility of 09MnNiDR＇s HAZ is obviously improved. The research results indicate that the method that improves the impact ductility of HAZ by increasing Ni content is not effective and uneconomical, however, the method that improves HAZ toughness by increasing the content of micro alloy element Ti from 0.016 % to 0. 021%-0. 026 % is highly effective. By TEM and Thermo-calc thermodynamic software, the mechanism that Ti improves HAZ toughness is studied. The results indicate that when Ti content is increased, the amount of second is phase increased, its grain size is refined, and the thermal stability of second phase is improved. So the grain size of CGHAZ is refined and the width of CGHAZ is shortened. Finally the toughness of HAZ is improved.