Heat treatment process of LSAW steel pipe
First, a reasonable choice. Straight pipe joints should use a good micro-deformable straight seam steel pipe, for the serious segregation of carbide straight weld steel castings should be reasonable and heat treatment, the larger can not cast straight steel can be double-precision heat treatment. Reasonable choice of heating temperature control heating rate, the straight seam pipe can be slow heating, preheating and other ways to reduce heat balance straight seam pipe thermal deformation.
Second, the correct heat treatment process operation and reasonable heat treatment process is also an effective way to reduce the deformation of straight pipe joints. Longitudinal welded pipe deformation causes are often messy, but we only need to grasp the causes of deformation analysis, choose to avoid abnormal deformation method can reduce the deformation of straight pipe joints can also be controlled.
Third, straight seam steel should be pre-heat treatment to eliminate residual stress during processing. For straight seam steel pipe, where conditions permit, should be low-temperature vacuum heat treatment and quenching after quenching. Under the premise of ensuring the straight seam pipe hardness, try to use the pre-cooling, quenching or isothermal quenching process.
Fourth, the straight seam pipe planning should be reasonable, the thickness should not be too bad, the shape should be symmetrical, straight pipe joints to large deformation and deformation in order to master the law, to reserve the margin, the large, straight seam pipe can be a combination of programs. For some precision messy straight seam steel pipe, preheat treatment, aging heat treatment, quenching and nitriding heat treatment can be used to control the accuracy of the longitudinal welded pipe. When the patch straight seam trachoma, porosity, wear and other defects, choose cold welding and other small thermal impact repair equipment to prevent the occurrence of deformation process.