Micro-Controlling of Steel Quality through An Innovative Steel Making Process 830657
A lately established melting-refining-casting process for special steel and their qualities are described in this paper. The process consists of electric arc furnace melting, ladle furnace refining, vacuum degassing and continuous casting in this order. Such a complicated process has been put in the practice for the first time to manufacture particularly automobile steels.
One of the advantages of this process is the reduction of impurities such as oxygen and sulfur Oxygen is evacuated during vacuum degassing treatment and sulfur is controlled through ladle furnace refining. As a consequence, cold formability is improved significantly.
Mechanical reliability can be increased as well, and especially, it should be noteworthy that stress corrosion cracking of high strength fastners is able to be prevented by the reduction of sulfur.
Consistent quality is an another major advantage of the process. This is achieved with the minute control of chemistry through ladle furnace refining and vacuum degassing process. Continuous casting is also contributed to improve consistency through minimizing of segregation during solidification. An uniform-hardenability-steel and an uniform-heat treatment- distortion steel are examples of automobile steels taking this advantage.