Stainless Steel

The CLU converter process, which is a further development of the AOD process, is the most flexible process for stainless steel refining. Through the use of steam as an additional process gas all grades of stainless steel can be produced with low argon consumption, high productivity and low refractory wear.

CLU Process
The fundamentals of using steam in the converter lie in the reduction of steam. The effect of steam is twofold. When superheated steam is introduced in the converter it is decomposed into oxygen and hydrogen. The formed hydrogen gas will act as an inert gas to replace argon or nitrogen while the oxygen will take part in the carbon oxidation. Hence by using steam the consumption of the more expensive argon gas can be reduced. This can lead to considerable cost savings depending on the amount of steam introduced (use of 1 kg of steam substitutes 1.25 Nm3 Ar(or N2) and 0.625 Nm3 O2 in the converter).

The second effect comes from the fact that the reduction of steam consumes heat. This means an additional cooling benefit is obtained by utilizing steam in the process. Hence the CLU process gives a more flexible overall melting where solid material and steam is optimized to reduce cost and increase productivity (1 kg of steam replace 10 kg of scrap in terms of cooling capacity). A better temperature control and reduced refractory contact time through the effective use of steam also leads to lower refractory wear.

CLU Characteristics
• Argon consumption is low
• Need of expensive coolant material is reduced
• Process control is simplified
• Lining life is high
• Process time is reduced