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通过屈服强度和冲击韧性测试、组织分析,研究了两种焊接热输入条件下道间温度对10CrNi5MoV钢气体保护焊接头力学性能的影响。结果表明,随着道间温度从40℃提高到300℃,焊接热输入为8 kJ/cm和18 kJ/cm的焊缝金属屈服强度分别从868 MPa和855 MPa单调下降至728 MPa和693 MPa,-50℃冲击韧性分别从70 J和69 J升高至117 J和72 J(道间温度分别为200℃和100℃),然后降低至67 J和43 J;焊缝金属的组织差异是不同道间温度下焊接接头力学性能不同的原因。随着道间温度从40℃提高到300℃,焊缝金属中马氏体组织逐渐消失,粒状贝氏体组织逐渐增多,针状铁素体组织比例先增加再减少,含量最高时的道间温度与冲击韧性峰值水平相一致。
Through the yield strength and impact toughness test, microstructure analysis, the effects of the two kinds of welding heat input conditions on the mechanical properties of 10CrNi5MoV steel gas shielded welding joint were studied. The results show that as the interpass temperature increases from 40 ℃ to 300 ℃, the yield strength of weld metal with welding heat input of 8 kJ / cm and 18 kJ / cm decreases monotonously from 868 MPa and 855 MPa to 728 MPa and 693 MPa, respectively , The impact toughness at -50 ℃ increased from 70 J and 69 J to 117 J and 72 J respectively (the interpass temperatures were 200 ℃ and 100 ℃ respectively), then decreased to 67 J and 43 J; and the difference in microstructure of the weld metal was The reasons for the different mechanical properties of welded joints at different tunnel temperatures. With the increase of the interpass temperature from 40 ℃ to 300 ℃, the martensite in the weld metal gradually disappeared, the granular bainite gradually increased, the acicular ferrite increased first and then decreased, and the highest content of the interpass Temperature and impact toughness peak level consistent.