Measures to Prevent the SSAW Steel Pipe Heat Cracks
Date:2019-05-30 View(s):1261 Tag:Measures to Prevent the SSAW Steel Pipe Heat Cracks
In SSAW pipe welding process, there are many welding factors. It is necessary to dynamically weld curves in space. Moreover, the adjustment of forming and welding is relatively high. If the adjustment is appropriate, the hot crack can be avoided and the welding quality can be guaranteed.
1. Shaping control should be adjusted in the following aspects:
Firstly, it is necessary to ensure the accurate calculation of forming process parameters and release appropriate adjustments; secondly, fine adjustment and control of the deformation of the bending steel strip to minimize the curvature difference of the output side of the free edge; thirdly, correctly adjust the height of the welding pad to avoid excessive local stress of the joint.
2. Controlling welding factors:
(1) It is impossible to use the welding position when welding uphill. There is downhill welding in practice, because the internal weld of the spiral submerged arc welded pipe is not the main deformation zone. If the uphill welding is adopted, the deformation in the pipe is seriously insufficient and the tear in the weld is the easiest.
(2) Intra-articular deviation should not be too far from the center. Because it is too far away from the center, it is shown in the welding mushroom shape, high saddle ratio. Such a shape is not conducive to the discharge of welding impurities (slag cracking induction), stress and poor health.
(3) On the premise of ensuring overlap, the welding parameters should not be too large. For twin wire welding, the wire spacing should not be too large, too large or too large spacing of specification parameters, and the length of weld should be extended. Pipeline will inevitably be subjected to vibration and pull, tension, torsion and other impact forces in the process of advance, resulting in a slight increase in the possibility of crack growth.