轧制和焊接的管材，其金属晶格发生畸变，且产生大量的晶格缺陷，如点缺陷、位错、亚晶界、堆垛层等．这些缺陷使金属内部的能量升高，内应力增大，同时在轧制过程中也会造成管材外表面粗糙、麻坑、尺寸改变等，严重地影响了管材的使用性能．采用退火工艺以后，可消除变形和焊 Rolled and welded pipe, the metal lattice distortion, and produce a large number of lattice defects, such as point defects, dislocations, subgrain boundaries, stacking layers. These defects make the energy inside the metal increase, the internal stress increases, while the pipe will also cause rough outer surface of the pipe, manger, size changes, seriously affecting the performance of the pipe. After the annealing process, the deformation and welding can be eliminated