1, bubbles
This situation generally occurs in the weld center position, is mainly due to the presence of hydrogen bubbles form. To eliminate such defects, it is necessary to remove the impurities in the wire and weld, including rust, oil, water and moisture, such as material. Then the moisture removal, plus appropriate current increase and decrease of welding speed and slow down the melting metal solidification rate, there will be significantly improved.
2, sulfur crack
This is because the sulfide in the sulfur segregation band is brought into the weld metal in the welding process, which produces a number of cracks. In order to prevent this, as long as the use of sulfur segregation with a small semi killed or killed steel can be, but do not forget the weld surface and flux cleaning and drying is also very necessary.
3, thermal crack
To eliminate the crack is relatively simple, as long as the arc and the arc extinguishing installation of a pad, also in volume of at the end of the weld, the spiral welded steel pipe is reversed and the welding stitch welding. And this crack in the welding seam stress is very large, it is particularly easy to appear, so be sure to control the stress of the welding seam.
Easily identify the defects in the weld zone, we can promptly put the crisis to kill, to ensure that our spiral welded steel pipe is not defective.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)
