中俄东线-45℃低温环境油气管道工程用X80钢级Φ1422 mm×33.8 mm感应加热弯管研发

Development of X80 Φ1 422 mm×33.8 mm Induction Heating Bend for China-Russia East Nature Gas Pipeline Project in-45 ℃ Low Temperature Environment

为了解决低温环境下弯管脆断的问题,满足我国长输油气管道低温站场用钢管的需求,针对油气输送用X80钢级直缝埋弧焊管焊接接头在回火热处理后,焊缝金属夏比冲击韧性存在明显回火变脆的现象,对多丝单道焊和单丝多道焊的直缝埋弧焊管焊接接头进行了焊后箱式炉热模拟研究,并选用整体热煨制方式,试制了感应加热弯管,进行了理化性能评价。结果显示,焊缝中细小的针状铁素体板条随回火温度升高而合并粗化,是导致焊缝低温韧性显著降低的原因;采用淬火+回火热处理方法,可有效抑制焊缝夏比冲击韧性随回火加热温度的递增而恶化的趋势;X80钢级Φ1422mm×33.8mm单丝多道焊感应加热弯管母管经淬火+回火热处理后,完全满足-45℃低温条件下中俄东线低温管道工程设计要求。

In order to solve the problem of brittle fracture of the bend in the low temperature environment and meet the demand of low temperature steel pipes for long-distance oil and gas pipelines in China, aiming at the phenomenon that the Charpy impact toughness of weld metal of X80 longitudinal submerged arc welded pipe becomes brittle after tempering heat treatment, the thermal simulation of the welded joints of longitudinal submerged arc welded pipe with multi-wire single-pass welding and single-wire multi-pass welding are carried out in a box tape furnace after welding, the induction heating bend is manufactured by whole hot-bending method, and the physical and chemical properties of the bend are evaluated. The results show that the coarsening of fine acicular ferrite lath in weld with the increase of tempering temperature is the reason for the decrease of the low temperature toughness of weld. The worsening trend of Charpy impact toughness of weld with the increasing tempering temperature can be effectively suppressed by quenching and tempering heat treatment. X80 Φ1 422 mm×33.8 mm induction heating main pipe with single-wire multi-pass welding after quenching and tempering heat treatment can fully meet the requirements of low temperature pipeline engineering design of China-Russia East nature gas pipeline project at -45 ℃.