An Overview of High Purity Welding
For October, we’re celebrating high purity welding here on CarmenElectrode.com, starting with this overview. High purity welding procedures are utilized in a variety of industries where the metal being welded requires a super clean environment in order to achieve optimal weld results.
In the aerospace industry, as you may well imagine, obtaining a super strong weld joint is imperative to the safety success of an aircraft. A while back, The Fabricator magazine featured an article on Orbital welding for the space program, where every weld must pass the “highest of purity and integrity tests.” These welds must hold up deep in space!
Nuclear piping is another industry where you don’t want any weld to fail. Titanium, a notably reactive metal, is a good choice for the nuclear power industry due its resistance to seawater corrosion—not to mention the strength of titanium, when welded correctly of course. Arc-Zone’s own Jim Watson (aka Joe Welder) prepared a good overview of titanium welding a while back.
Another industry that comes to mind for high purity welding is food processing (including dairy and breweries) where stainless steel pipe systems carry food product from one place in a factory to another. In food processing, the welds must all be smooth and free of any occlusions, or any little nooks and crannies where bacteria could grow. To achieve that kind of weld, the inside of the pipe—the backside of the weld—must be protected from oxygen as much as the front side. And you can’t stop with just a good weld—finishing is important too. Check out these tips, also from The Fabricator magazine, “Finishing stainless steel for food-grade applications.”
In piping systems where good clean water needs to be delivered, such as the pharmaceutical industry, the pipes must also be free of contamination, and not prone to rust. The semiconductor industry also requires high purity welding to ensure smooth welds (inside and out) and prevent contamination of the system. This video demonstrates the inspection of the inside of the weld…
Reactive metals, like stainless steel, titanium, and inconel also require attention not only to the weld process and specialized accessories, but to the weld environment as well. Some applications may require a Clean Shop with a dedicated area for storage of materials and a dedicated work area where air drafts and contamination can be minimized, or a purge chamber. For a run-down on accessories for creating high purity welds, check out the article on JoeWelder.com, “Overview of accessories for high purity welding.”