Heat treatment process of steel saw pipe
First, make reasonable choices. The straight pipe joint should be made of a good micro-deformable material, and the cast steel with serious carbide segregation should be transferred reasonably by heat treatment. The bigger straight pipe steel which can not be cast can be treated by double refining heat treatment. Reasonable selection of heating temperature and control of heating speed can slow the heating of straight seam steel pipe and reduce the thermal deformation of heating balanced straight seam steel pipe by preheating.


Secondly, correct heat treatment process operation and reasonable heat treatment process are also effective ways to reduce the deformation of straight pipe joints. The reason for the deformation of straight-seam steel tube is often messy, but we only need to grasp the initial cause of deformation analysis, and choose the method to avoid the abnormal deformation of straight-seam joint can be reduced or controlled.


Thirdly, the straight seam steel pipe needs to be pre-heat-treated to eliminate the residual stress of the processing process. For straight seam steel pipe, low temperature vacuum heat treatment and quenching after quenching should be used as far as possible when conditions permit. On the premise of guaranteeing the hardness of the straight seam steel bar, the pre-cooling, step cooling and quenching or isothermal quenching process should be adopted as far as possible.


Fourth, the planning description of straight-seam steel pipe is reasonable, the thickness is not too thick, the shape is symmetrical, the straight-seam steel pipe joint large deformation master rules, spare margin, large, straight-seam steel pipe can be combined use plan. Pre-heat treatment, aging treatment, quenching and nitriding heat treatment can be used to control the accuracy of straight pipe joints for some precision and disordered straight seam steel pipes. When there are defects such as grit, pore, wear and tear in the straight seam of the patch, the repair equipment of small heat-affected patch such as cold welding can be selected to prevent the deformation process.