Weld Hot Cracking and Corrosion Resistance of High Silicon Containing Stainless Steels : Study on Welding of High Silicon Containing Stainless Steels

The corrosion resistance and weld hot cracking of high silicon containing stainless steels were investigated from a metallurgical point of view. A stainless steel has good corrosion resistance due to the passive film. However the stainless steels differ from the intergranular corrosion in the high potential region, for example, in the boiling nitric acid solution containing strongly oxidizing ions. The addition of silicon into stainless steels is effective for the improvement of corrosion resistance in these evnironment. However, it has been reported that in the weld metals containing high level of silicon the selective corrosion and weld hot cracking very often occur. The effect of the solidification mode of weld metals on the weld hot cracking and the selective corrosion in the boiling solution of 8MHNO3 containing 0.2 g/l Cr6+ ion was investigated. The both of weld hot cracking and selective corrosion occurred due to the silicon enriched phase, which tended to form under the primary austenitic solidification, and can be prevented by the fully ferritic solidification even though with a silicon content of approx. 3.5%.