Novel Casting Technology Preventing Slab Transverse Corner Cracks of Typical Micro-alloyed Steels

Abstract

A novel casting technology based on chamfered mould was successfully developed in order to control slab transverse corner cracks of typical micro-alloyed steels. By using the established models for the typical niobium, vanadium, titanium micro-alloyed steels, the slab casting process during solidification and straightening can be simulated for both conventional and chamfered moulds. The simulation results provide guidelines for designing chamfered mould with optimum geometry in terms of heat transfer, slab strain and controlling of slab cracks. Results from the industrial applications over last few years confirm that the slab corner temperature at straightening segment is about 100 ℃ higher by using a chamfered mould than the conventional mould. Consequently, the slab transverse corner cracks can be reduced by more than 99.5% during casting of micro-alloyed steel, such as X65 (yield strength is 450 MPa), Q550D (yield strength is 550 MPa) and Q690 (yield strength is 690 MPa). This novel casting technology with chamfered mould has been successfully applied by more than 20 major steel plants in China such as Shougang Jingtang Iron and Steel Company, Handan Iron and Steel Company, Anshan Iron and Steel Company, etc. and brought enormous economic benefits to the users.