Residual Stress

The residual stress eliminates the self-phase-balanced internal stress remaining in the object after the external force or the uneven temperature field. Both machining and strengthening processes can cause residual stresses. Such as cold drawing, bending, cutting, rolling, shot peening, casting, forging, welding and metal heat treatment, etc., due to uneven plastic deformation or phase change may cause residual stress. Residual stress is generally detrimental. For example, after improper heat treatment, welding or cutting, residual stress may cause warpage or distortion or even cracking of the part. Or after quenching and grinding, cracks may appear on the surface. The existence of residual stress sometimes does not appear as a defect immediately, and cracks and fractures occur when the part is superimposed on the strength limit due to the superposition of the working stress and the residual stress during the work. Most of the residual stress of the part can be eliminated by appropriate heat treatment. Residual stress can sometimes be beneficial as well, and it can be controlled to improve the fatigue strength and wear resistance of the part.

During the manufacturing process, the steel pipe will be affected and affected by various processes and other factors; when these factors disappear, if the above-mentioned effects and effects of the components cannot be completely disappeared, there are still some effects and effects remaining on the components. Inside, the effect and influence of this residue. Also called residual stress.

Residual stress is the stress that exists when the object remains in balance while there is no external factor.

Any stress that has no external action and maintains self-phase equilibrium inside the object is called the intrinsic stress of the object, or called initial stress, also known as internal stress.