DeP converter from Siemens commences operation at Tangshan

A DeP converter from Siemens has commenced operation at the Chinese steel producer Tangshan Stainless Steel Co. Ltd., a subsidiary of Tangshan Iron & Steel Group Co. Ltd. The converter installed at the Tangshan plant serves to reduce the crude steel's phosphorus content. Thus, Tangshan can produce high-grade carbon steels, which are processed further to high-strength sheets for the automobile industry at a cold rolling complex newly constructed by Siemens.

Tangshan Iron and Steel belongs to the Hebei Iron and Steel Group, China's largest steel producer with annual production of around 46 million metric tons (2013). Last year, Siemens had received the order from Tangshan Iron and Steel to supply a complete cold rolling mill for the Tangshan location in the Hebei province. The plant is designed for annual production of 1.6 million metric tons of cold rolled strip. As an excessive phosphorus content increases the steel's brittleness, this content must already be clearly reduced in the liquid phase.

To achieve this goal, Siemens converted an existing AOD converter to the DeP converter. In it, dephosphorization takes place via a two-stage process. First, oxygen is blown in to oxidize the phosphorus. In a second step, the oxidized phosphorus is bonded to lime and is gathered in the slag. Six bottom blowers support and accelerate the chemical reaction.

The converter possesses a tapping weight of 110 metric tons and can also be used for decarburization. Siemens was responsible for engineering, supplied the process automation and supervised installation and commissioning. Moreover, Siemens advised the operating personnel on how to handle the new process.

Further information about solutions for steel plants, rolling mills and processing lines can be found at www.siemens.com/metals.