大直径厚壁螺旋埋弧焊管钢带对接焊缝裂纹分析

针对输水及热力管线大直径厚壁螺旋埋弧焊管生产过程中，保留钢带对接焊缝出现的裂纹缺陷问题，结合钢带对接埋弧焊的工艺和设备特点，分析了裂纹产生的原因。分析指出，钢带对接焊缝裂纹主要是由于焊缝中低熔点夹杂物、焊缝熔池的拘束应力和热轧钢卷板材头尾部分未矫平、在合缝对焊时产生的变形应力以及剪切头尾断面存在超过70％的撕裂等现象的影响。最后提出了避免裂纹产生的措施。

Crack Analysis of Butt Weld Seam of Large Diameter Thick Wall Spiral Submerged Arc Welding Pipe Steel Belt

Aiming at the production of large diameter thick-wall spiral submerged arc welding pipe of water and heat transmission pipeline, the crack defects of steel belt butt welding are preserved, and the causes of crack are analyzed in combination with the technology and equipment characteristics of butt welding. The analysis show that the crack of steel belt butt welding is mainly due to the low melting point inclusion in the weld, the constraint stress of the weld pool, the non-straightening and leveling of the head and tail parts of the hot-rolled coil sheet, the deformation stress generated during the joint welding, and the tearing of over 70% of the shear head and tail section. The measures to avoid cracks are put forward.