When you think of ground-breaking and game changing, a lot of things undoubtedly come to mind. For welders, it might be titanium welding. In its early days, all titanium welding used to be carried out inside glove boxes – significantly limiting the size of projects a titanium welder could undertake. Not anymore.
The Limitations of an Emerging Science
Titanium is a difficult material that is especially sensitive to contamination. To shield titanium from the embrittling effects of elements like nitrogen, hydrogen and oxygen, virtually everyone in the industry used to conduct all titanium welding inside of glove boxes. These are airtight boxes filled with inert gas and fitted with rubber gloves, which the welder engages with while standing outside of the box. This limited manufacturers to welding only parts that were small enough to fit inside of these boxes, which is horribly insufficient for larger critical-use applications.
The Titanium Welding Revolution
- It is possible to create high-quality welds in the open-shop environment.
- Welds must be protected while they are solidifying, and the reverse side of welds must also be shielded.
- Trailing shields that use inert gases like argon or helium can protect welds from contamination.
- Local purges offer more flexibility than purging large volumes.
- Shielding gases must be clean and devoid of moisture.
- Titanium welding requires a higher degree of cleanliness than is required for other metals. Lint-free paper towels and acetone works best.
- Ductile welds cannot be produced by oxygen acetylene welding, or any method using active gases, coated electrodes or traditional fluxes.
- The best results usually come from gas tungsten-arc welding, laser beam welding or electron beam welding, however, gas metal-arc, spot, seam and flash welding may all be used depending on the demands of the application.
- There should be no surface colors on finished welds, and different colors indicate different severities of problems that corrupted the welding process. Under no circumstances should a welder make a second pass if the first pass resulted in surface discoloration until the problem has been corrected.
Through brainstorming, experimentation and a whole lot of trial and error, a few crucial discoveries were made that would go on to liberate titanium welders from the confines of glove boxes, including:
When these discoveries were shared with welders across the world, the practices developed quickly became standard in the industry. The entire industry benefits from shared knowledge. Firms that don't regularly work with titanium can continue to design inferior shields, fail to clean well enough and produce low-quality welds, which are unreliable and prone to failure in the field. Anyone who works with titanium is encouraged to learn about the history of the craft and the evolution of techniques that are now considered common best practices.
Gone are the days of being forced to limit your welding to what can fit inside a certain space. With the knowledge and skills available today, titanium welders are able to think outside the (glove) box.