The piercing process is at the top of the process chain, which starts with the solid steel billet and ends with the seamless tube. It is of crucial importance for the subsequent quality of the finished tube: the billet must demonstrate excellent surface and tolerance characteristics straight after piercing. Only then is it possible to produce high-quality tubes with flawless surfaces and high dimensional accuracy. The high-performance cross-rolling mills from SMS group are perfectly designed for this, enabling particularly cost-effective production at the same time.
Cross-roll piercing ranks as the leading piercing method for seamless tubes and offers considerable advantages compared to alternative methods such as piercing presses or press-piercing mills. Plant owners are able to process heavier billets as well as achieve measurably closer wall thickness tolerances.
As an alternative to the 2-roll piercing mill, 3-roll piercing mills are also used for the piercing process. This further improves the wall thickness quality of the hollow.
SMS group has continuously further developed the cross-roll piercing process with several inventions, such as hydraulic gap control. Today's high-performance cone-type piercers produce particularly thin-walled hollow blooms with very tight tolerances and highest productivity. These innovations give advantages during the subsequent processing stages in the production of seamless tubes: the loads on the elongating and sizing units are reduced and the production range can be increased. This enables tube manufacturers to produce more cost-effectively – even in the case of large dimensional ranges, small batch sizes and low capacities.