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针对西气东输二线X80高强度高韧性厚壁管线钢管双面埋弧焊接工艺特点,采用Gleeble1500热模拟试验和实物焊接试验,研究分析了内焊缝(一次焊缝)受到外焊(二次焊接)热循环后组织与性能变化情况。通过SEM、光学显微镜等进行了微观组织分析并做力学性能测试。结果表明,一次焊缝受到二次焊接热循环峰值温度在(α+γ)两相区范围时发生脆化,韧性降低22%;而一次焊缝在外焊二次热输入为20 kJ/cm时,冲击韧性最好;二次焊接在一次焊缝中形成了焊接临界粗晶区(WICHAZ),呈现粗大的条状铁素体,板条间为排列成行M-A组元或渗碳体,硬度由212HV5迅速增加到261HV5,韧性也随之变差。
According to the characteristics of double-sided submerged arc welding process of X80 high strength and high toughness thick-walled pipeline steel pipe for West-to-East Gas Pipeline Project, Gleeble1500 thermal simulation test and physical welding test were conducted. The internal weld (primary weld) Welding) thermal cycling organization and performance changes. Through SEM, optical microscopy and other microstructure analysis and mechanical properties test. The results show that the primary weld embrittlement occurs when the peak temperature of the secondary welding thermal cycle is in the range of (α + γ), and the toughness decreases by 22%. When the secondary weld heat input is 20 kJ / cm , The best impact toughness; secondary welding in a weld to form a critical weld grain area (WICHAZ), showing coarse strip ferrite, slats arranged in rows MA elements or cementite, hardness 212HV5 rapidly increased to 261HV5, toughness also will be worse.