Porosity Causes of LSAW Steel Pipe

As we all know, the weld quality determines the quality of the pros and cons of the pipe, once the weld pipe stoma, which not only affect the pipeline weld tightness, resulting in pipeline leakage, and will become the trigger point of corrosion, seriously reduce the weld strength and toughness. In general, the moisture, dirt, scale and iron filings in the flux, the composition and thickness of the welding, the surface quality of the steel plate, the side plate treatment, the welding process and the lsaw steel pipe forming process may be the cause of the porosity. Therefore, when the welding temperature is high, the weld is excessively burned to form a through-hole. When an appropriate amount of CaF2 and SiO2 are contained, the reaction absorbs a large amount of H2 to form HF, which is highly stable and does not dissolve in the liquid metal.

To prevent the formation of hydrogen pores; weld forming coefficient is too small, the shape of the weld narrow and deep, gas and inclusions are not easy to float, easy to form pores and slag; steel plate edge should be set up rust and burr clearance device, in order to reduce the possibility of generating pores. Welding temperature is a key parameter affecting the quality of the weld, the location of the removal device is best installed in the milling machine and the disc shears, the device structure is the side of the two upper and lower position adjustable gap of the active wire wheel, flux accumulation thickness is generally 25-45mm, flux particle size, the density of the thickness of the stacking time to take the maximum value, while the minimum; high current, low welding speed stacking thickness to take the maximum value, in addition, the summer or In order to reduce the impact of magnetic bias blow, should make the connection position of the welding cable on the workpiece only possible away from the welding terminal, to avoid part of the welding cable in the workpiece to produce secondary magnetic field; It should be appropriate to reduce the welding speed or increase the current, thus delaying the weld pool of metal crystallization rate in order to facilitate the escape of gas at the same time, if the strip delivery location is not stable, should be adjusted in time to prevent frequent fine-tuning front or rear, the bridge to maintain forming, resulting in gas escape difficult;