Behind each of our tubes and pipes is a high-precision manufacturing process. From the selection of high-quality starting materials, through hot or cold forming, to precise machining, coatings, and comprehensive testing, every step of the manufacturing process is designed to achieve the highest quality. Using state-of-the-art production facilities, specialized materials technology, and quality assurance that far exceeds industry standards, we manufacture premium-quality steel tubes for applications where every detail counts.
Steel tubes from Mannesmann Precision Tubes are manufactured using two production routes. For seamless steel tubes, round-shaped continuous cast billets serve as the raw material; these are hot-rolled into so-called hollows, which are then further processed into high-quality precision steel tubes in the cold-drawing shops. The production of welded steel tubes, on the other hand, is based on hot-rolled wide strip, from which welded, dimensionally rolled precision steel tubes are first produced. Through subsequent cold drawing, these can be further refined into welded, cold-drawn precision steel tubes.
At Mannesmann Line Pipe, longitudinal seam welding is performed using the high-frequency induction (HFI) resistance pressure welding process. In this process, the strip is formed into an endless open-seam pipe and passed through a coil carrying a high-frequency current, which heats the edges of the strip to welding temperature. In the hot-strip edger mill, the heated edges are welded into a homogeneous longitudinal seam using pressure rollers without any filler metal, and the resulting inner and outer beads are immediately removed. A subsequent inductive heat treatment adjusts the microstructure of the seam to match that of the base material before the tube string is straightened, calibrated, and cut to length into individual tubes.
We have been successfully using the Helical Two Step (HTS) manufacturing process since 1986 and we continue to refine the process as the first company to adopt it. The key difference from conventional spiral tube manufacturing lies in the clear division of the process into two coordinated steps: First, the tube is formed using continuous tack welding; then, the inner and outer seams are submerged-arc welded on separate welding stations.