The continuous rolling process – using mandrel mills – has been successfully used as a method of producing seamless steel tubes since the 1970s. The mandrel mill comprises several two-roll stands, which roll the hollow longitudinally to form a shell. SMS PQF^® (Premium Quality Finishing) plants allow for operation at maximum efficiency, optimized operational costs, and reduced downtimes without compromising on productivity and high-quality results; while conventional seamless tube lines cannot viably compete with the high-precision PQF^® quality, nor with its levels of productivity.

A PQF^® mill consists of up to six stands, with three driven rolls each. The force is therefore applied more uniformly across the circumference of the rolls than it is with MPM (Multistand Pipe Mills) technology featuring a conventional two-roll arrangement.

Whether high-alloy steel tubes or particularly thin-walled precision tubes, our PQF^® technology is designed to produce even the highest-grade products efficiently and reliably. By using less material, it achieves better output than conventional solutions. This ensures savings in tool and energy costs thanks to low reheating during the rolling process and thus a smaller CO₂ footprint.