Manufacturing of square tube:

Many defects of square tubes are formed in the process of piercing, so the piercing process of tube blank is the key process of consuming square tubes. The main difficulty of high alloy piercing is the low piercing performance. In order to ensure the quality, it is necessary to rationally select the deformation parameters of piercing. A small tightening amount will cause instability in the piercing process, so the critical tightening amount per hour head should be set at about 7% of the previous tightening amount, or it will not bite, resulting in increased movement or front jamming. The increase of shrinkage in front of the plug will also form a cavity and sink the defects in the sound. Therefore, if the problem is to be suppressed, the billet should be centered, and the empty depth of centering should be compared according to other steel grades.