Stainless Steel Pipe Welding

by Darcy Singh manager Seamless Stainless Steel Pipe welding is gravy work. Always has been. Always will be. If you can do it and do it well, you are the man and you will never go hungry. But it takes some attention to detail to do it right. The main thing that separates the men from the boys or should I say, the real welders from the rod burners is the willingness to follow procedures for welding stainless steel. Procedures like waiting for the pipe to cool in between passes, keeping the hot tip of the rod shielded with argon, snipping the tip of the tig welding rod when it gets crapped up, keeping your tungsten sharp. One of the main procedures I am talking about is PURGE. Welded Stainless Steel Mechanical Tube absolutely has to be purged with argon gas in order to prevent sugaring. Sugaring is also called granulation but it is severe oxidation no matter what you call it. You cant even get away with tack welding without an argon purge that shield the back side or inside of the pipe. So how do you do it? How do you protect the back side with argon? Usually it is done with aluminum duct tape. The ends of a stainless steel pipe are taped shut and the whole inside is purged with argon gas. Even the opening in the pipe joint itself is taped so that argon can fill the entire pipe and push out any oxygen. The tape is peeled back just enough to get a tack once the pipe is purge enough. What is enough? www.3sstainless.com The only way to tell for sure is with an oxygen analyzer. A bic lighter will not do the trick. Even 2% oxygen content will blow out a bic lighter. And 2% oxygen will result in a black root pass. There are some other down and dirty ways to check the purge but an oxygen analyzer is the sure way. Here are a few tips that will help you get a good purge on the stainless steel pipe you weld. Make sure there is no water inside the pipe...not even a drop. One single drop of water will throw a monkey wrench in your purging until it evaporates. Remember Once you verify a good purge, you are ready to tack. Peel the tape back just enough to tack and let cool a bit and re tape. Then tack again 180 degrees apart. Continue until all tacks are in place.

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Created on Dec 31st 1969 18:00. Viewed 0 times.

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