I have been presented the following scenario regarding a plasma welding "problem" and have been asked my solution. I have provided limited answers based on my knowledge, but would like to solicit additional feed back from those who may have better solutions to offer.

A company recently started receiving product from a new supplier. This supplied product is a perforated flat made out of 301 SS with a number 4 finish. The material is then rolled and plasma butt welded together to form a conical section. The original supplier took a flat blank and hard-tooled the perf pattern. The new supplier is using a perforating line that currently uses a Calgon water soluable lubricant to process.

Problem: With the old supplier’s product there were relatively few welding problems. With the new supplier’s material they are experiencing some welding problems. The weld starts out O.K., but about halfway through the weld “brown” spots are seen in the weld. It is believed that the spots are structurally acceptable, but cosmetically not.

Question: Is this a problem with new supplier’s processing method (eg. the lubricant)?

Any suggestions, solutions, or other potential areas to investigate would be appreciated.

Thanks,

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