The porosity of the large-diameter spiral pipe seam not only affects the fineness of the welding seam of the pipeline, causing leakage of the pipeline, but also becomes the induction point of corrosion, which seriously reduces the strength and resistance of the welding seam.The bubbles in the spiral steel pipe mostly occur in the center of the weld bead, the main reason is that the hydrogen is still hidden inside the weld metal in the form of bubbles.At the same time, the moisture, dirt, oxide scale and iron filings in the flux, the welding composition and covering thickness, the surface quality of the steel plate and the treatment of the steel plate side plate, the welding technology and the steel pipe forming technology may induce the generation of pores on the spiral steel pipe.

The control measures for the welding quality of ssaw steel pipes are mainly pre-control and in-process control.

Color penetrant inspection of welds is one of the effective methods to inspect the surface defects of welded joints. It can effectively and quickly check for defects in the welding of erw steel pipes.Compared with magnetic particle inspection of welds, it has the advantage that it is not limited to ferromagnetic materials, and its application range can be extended to non-magnetic materials such as austenitic stainless steel and alloys.

Seamless line pipes are mainly used to transport high-pressure oil and gas near the wellhead. With the deepening of oil and natural gas exploitation, there are more and more oil and gas wells with complex exploitation conditions and in sulfur-containing environments, and the problem of hydrogen sulfide corrosion is becoming more and more serious. The development of sulfur-resistant seamless line pipes is imminent. The addition of Cu and Ni can improve the HIC performance of the seamless line pipe material, reduce the S content in the steel, and reduce the sensitivity of hydrogen bubbling by spraying silicon calcium powder.

Rectangular tube, also known as square tube or rectangular tube, is a kind of square steel with a hollow section. At present, there are two main forming processes for square tubes, which are the round-to-square and the direct-to-square.

Eddy current testing and magnetic flux leakage testing are both commonly used non-destructive testing methods for seamless steel pipes. The two mainly detect the surface and near-surface defects of steel pipes. Both have their own focus and limitations. Choose according to the situation.