In complex piping systems, there are often difficulties due to space position conditions, resulting in installation difficulties: the formed pipe can not be loaded; bending over, coming over, making up the installed pipe will inevitably produce local Cold correction. Depending on the pipe diameter and the specific conditions on site, the amount of cold correction ranges from a few millimeters to tens of millimeters, and some hundreds of millimeters. Practice has proved that the larger the amount, the higher the internal stress, and the installation stress of these residues in the pipeline system is undoubtedly a great relief.
