CLU process for Stainless Steel Production Dec28

CLU process for Stainless Steel Production...

CLU process for Stainless Steel Production Stainless steel production process has some basic features such as carbon (C) removal, deoxidation and desulphurization. In the production process, these operations are generally combined with some alloying with solid material as well as nitrogen (N2) control.  These requirements are met in different ways in various processes being deployed for the production of stainless steel. The CLU process is similar to the AOD (argon oxygen decarburization) process for making stainless steels. CLU refers to the Creusot-Loire Uddeholm process for stainless steel production. It also uses liquid steel from an electric arc furnace (EAF) or any other similar primary steel making furnace.  The major impetus for the development of the CLU process was the idea to use superheated steam as the diluting gas instead of argon (Ar) gas which is used in the AOD process. Superheated steam has been used as a process gas in stainless steel production since the early 1970s when this technology was developed at Uddeholms Degerfors steel plant in Sweden. In France a similar development took place within the Creusot-Loire group. The developed process was named Creusot Loire Uddeholm (CLU) process. The converter originally used in CLU process was a bottom blown converter thus differentiating it from the side blown AOD converter. However, presently CLU process with the use of a side blown converter is also available. The first commercial plant using the CLU process was built in 1973 by Uddeholm. Between 1973 and 2003 stainless steel was produced in Uddeholms Degerfors steel plant in an 80 ton converter where superheated steam, Ar, N2, oxygen (O2) and compressed air were used as process gases. The converter in the Degerfors steel plant was operated for 30 years as a CLU process for stainless steel production before...

Stainless Steel Manufacturing Processes May04

Stainless Steel Manufacturing Processes...

Stainless Steel Manufacturing Processes Stainless steels contain from 10 % to 30 % chromium. These steels also contain varying amounts of nickel, molybdenum, copper, sulphur, titanium, and niobium etc. The majority of production of stainless steel was through the electric arc furnace (EAF) till around 1970. With the use of tonnage oxygen in steel production, the EAF stainless steel making practice changed. Oxygen gas could be used for improving the decarburization rate. This could be achieved by injecting high oxygen potential but it was accompanied by the adverse reaction of extensive oxidation of chromium to the slag. This necessitated a well defined reduction period in which ferro silicon was used to reduce the oxidized chromium from the slag. Production of stainless steel started by duplex process with the successful development of argon oxygen decarburization (AOD) converter process. Though duplex process with AOD converter is the prominent one, there are several duplex processes are being used today for making stainless steels. In these processes there is an EAF or similar furnace that melts down scrap, ferroalloys and other raw materials to produce the liquid steel. This liquid steel, which contains most of chromium and nickel as well as some other alloying elements, is the charge of the converters. The converters are used to achieve low carbon stainless steels. The versatility of the EAF-AOD duplex process led steelmakers to re-examine the use of different converters for melting of stainless steels. This led to the development of several other converters for duplex processes. The development work to make stainless steels using conventional BOF (basic oxygen furnace) had begun in the late 1950s and early 1960s. By the mid 1960s, some steelmakers were using existing BOF converters for a partial decarburization followed by decarburization in a ladle under...