Above: A weld of two tubes of 316L each with 0.008% sulfur.

Weld of 316L tubes. Top tube was 0.002% sulfur, lower tube was 0.014% sulfur.

This paper was presented at the SEMI Workshop on Stainless Steel in October, 2000. The discussion was concerned with the effects of sulfur on the autogenous orbital welding of 316L stainless steel tubing and pipe. Approaches to the successful orbital welding of low sulfur heats of stainless steel, including the use of insert rings made from heats of stainless steel with higher sulfur contents than the base material, and the use of pressure balancing to control the weld bead profile were presented.

The issue of the ideal sulfur content of 316L stainless steel for autogenous orbital welding is presently under discussion by both the SEMI Standards organization and the A.S.M.E. Bioprocessing Equipment Standard (BPE '97) committees. The outcome of decisions made by these groups will have a significant effect on the welding and fabrication practices in the semiconductor and pharmaceutical industries.


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