TISCO Group's stainless steel cold rolling production line successfully rolled off the first 8.0mm ultra-pure steel hot coils. It means that TISCO's thick ultra-pure ferritic stainless steel has broken through the limit specification design capability. The core competitiveness of TISCO's products continues to increase, and the market benefits are further highlighted while meeting the market variety application. Thick ultra-pure ferritic stainless steel is mainly used for high-end automotive flanges and other parts. Its annual domestic demand is about 5,000 tons, and the export order volume is about 1,000 to 2,000 tons.

TISCO has always used the process route of "hot rolling mill rolling shearing + hot rolling mill annealing and pickling" to open the flat plate to produce thick ultra-pure ferritic stainless steel, and its thickness specification is >6.0mm. Not long ago, TISCO Stainless Steel Cold Rolling Plant received an order for trial production of ultra-pure ferrite with a thickness specification of 8.0mm. The thickness of the steel plate only increased by 2.0mm, which is a great test for the entire R&D team. To meet customer needs, the whole R&D team launched technical research from the production process. The welding of ultra-pure ferrite with a thickness of 8.0mm is more difficult, which makes it critical to master the requirements of various performance parameters of online annealing furnaces and welds. After receiving the task, the factory organized the main welders and experienced masters to readjust the welding process parameters and track and analyze the welding situation on site. The welding process parameters were finally confirmed through tensile and bending tests and sampling analysis after welding. After welding, the welds of thick ferritic stainless steel are easily opened when passing through the online annealing furnace, and the subsequent bending of the line is prone to open welding, and the uncertainty of production is high. After tracking and observing, the factory team took measures to track the welds along the entire line so that problems could be found and dealt with in time.

The 8.0mm thick ultra-pure ferrite has strict requirements for the annealing process. Problems such as narrow process windows and inappropriateness are very likely to cause brittle fractures. After multiple sampling and analysis and laboratory test research with product engineers from the technical center, a reasonable annealing process was finally determined. At present, the product performance surface is significantly better than the quality of previous products, and user feedback is also good, realizing the ultra-pure and stable production of this specification thickness. TISCO will continue to face the market actively visit users, timely optimize and adjust product variety structure, and improve operations according to market changes.