How to stress annealing seamless steel tube
Seamless steel pipe is heated to a certain temperature (usually in the phase transition temperature or the recrystallization temperature or less), holding for some time, and then slowly cooled to remove the annealing process within a variety of precision seamless steel pipe stresses.
In the press working, casting, welding, heat treatment, machining and other processes, the article may produce stress. In most cases, after the end of the process, the metal will remain part of the internal residual stress. Residual stress can lead to rupture of the workpiece, deformation or dimensional change, residual stress also increases the chemical activity of the metal, in particular, the residual tensile stress is likely to cause intergranular corrosion cracking. Therefore, the residual stress will affect the performance of precision seamless steel tubes or cause premature failure of the workpiece.
When stress relief annealing, 15CrMo seamless steel pipe at a certain temperature by the action of internal local plastic deformation (when the stress exceeds the yield strength of the material at this temperature) or local relaxation (when the stress is less than the temperature of the material yield strength time) so that the residual stress relaxation and achieve the purpose of elimination. When stress relief annealing, the workpiece is generally slowly heated to a lower temperature (gray cast iron is 500 ~ 550 ℃, precision seamless steel pipe is 500 ~ 650 ℃, non-ferrous metal stampings for the recrystallization initiation temperature), for a period of time after slow cooling, in order to prevent new residual stress.
In the press working, casting, welding, heat treatment, machining and other processes, the article may produce stress. In most cases, after the end of the process, the metal will remain part of the internal residual stress. Residual stress can lead to rupture of the workpiece, deformation or dimensional change, residual stress also increases the chemical activity of the metal, in particular, the residual tensile stress is likely to cause intergranular corrosion cracking. Therefore, the residual stress will affect the performance of precision seamless steel tubes or cause premature failure of the workpiece.
When stress relief annealing, 15CrMo seamless steel pipe at a certain temperature by the action of internal local plastic deformation (when the stress exceeds the yield strength of the material at this temperature) or local relaxation (when the stress is less than the temperature of the material yield strength time) so that the residual stress relaxation and achieve the purpose of elimination. When stress relief annealing, the workpiece is generally slowly heated to a lower temperature (gray cast iron is 500 ~ 550 ℃, precision seamless steel pipe is 500 ~ 650 ℃, non-ferrous metal stampings for the recrystallization initiation temperature), for a period of time after slow cooling, in order to prevent new residual stress.
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