By now you have heard us talk about our expertise in high purity welding. But, do most people really understand what High Purity Welding is? We will explain what high purity welding is, along with some of the acceptable standards for these high purity welds.
High purity welding is used in the semi-conductor, medical, and aerospace industries, to name a few. High purity welding is done in a cleanroom setting where there is a controlled environment, preventing fewer contaminants from entering the weld area. This is important because the gases or fluids going through the tubing need to remain very clean. We have a great video that explains this as well.
Weld quality and integrity is based mainly upon the penetration, oxidation, and bead of the weld. A weld is at its strongest when the bead fully penetrates the inner wall of the tubing. A partially penetrated weld is proven to be weaker.
In the industries that demand high purity welding, like semi and medical, the oxidation of the weld is another solid gage to the level of weld quality. Dirty welds, or welds with heavy oxidation, lead to contaminates getting into the contents of the system the tubing is servicing. To eliminate dirty welds, the welder purges them with an inert gas on the inside and outside, which helps reduce the oxidation levels to make a cleaner weld.
If your industry or project calls for a superior high purity weld, send it to a shop that has cleanroom capabilities. Saving time or cutting corners to reduce cost by going to just any weld shop will only come back to your desk in the end.
A trained eye can look at the beading of the welded joint and quickly tell the difference between a good weld and a bad weld. A good weld is very consistent in both spacing and width throughout the entire weld. If you inspect a bad weld, you will find a wide variation in the bead width and even the length.
*Comparison of weld beads: picture from autospeed.com