Important process for manufacturing seamless square tubes

Many defects of square tubes are caused in the perforation, so the transfer process in the billet is the key procedure for producing square tubes. The main difficulty in perforation of high alloy lies in the low perforation performance, in order to ensure the quality should be rational choice of perforation deformation parameters.

Small compression will cause the piercing process is not stable, so the critical compression amount of the top head should be in front of the compression amount of the general set at about seven percent, otherwise it will not bite, or even move to increase or front card. Increased compression in front of the top head will also form a hole cavity and sink sound inside the defects. So if you want to overcome the problem, the billet should also be centered, and the depth of the centering of the empty depth should be based on other steel to compare.

Hot-rolled rectangular tube, continuous casting billets, primary rolled plate as raw material, and then after the heating furnace, even in the use of high-pressure water, the surface of the phosphorus removal work, and then with the roughing mill, in the roughing mill is mainly cut off the head and tail of the rectangular tube, and then in the pipeline, and then fed to the finishing mill, computer-controlled precision rolling.

The square tubes are cooled in a laminar flow, rolled in a coiling machine, and then curled. However, when re-coiled, the thickness often appears as well as some sort of error in accuracy. This is no different than the edges are also prone to defects. Then the curling is done again, and after trimming there is a straightening process after the cutting head to ensure the thickness and accuracy of the rectangular tube.