2 industries that require tig welding certification are:
- Industrial piping, (including boiler tubes)
- Aerospace and aviation (manufacture and overhaul/repair)
For tig welding certification in piping, pressure vessels, and boilers, ASME section IX of the “Boiler and Pressure Vessel Code” specifies the criteria for acceptable welding tests.
For Aerospace tig welding, the American Welding Society (AWS) D17.1 – “Specification for Fusion welding for Aerospace Applications” is the code for welding certification tests.
More often than not, a 6G position welding test is required to certify for Pipe welding jobs. On many boiler jobs, 2″ heavy wall tubing is tig welded all the way out in the 6G position making the welder either switch hands, or at least get in some uncomfortable positions. That is why 6G position Tig welding tests are considered the most difficult.
Most of the time, sheet metal test pieces in the 0.020″-0.125″ thickness range are used for aerospace welder qualification testing. The 6G welding test is only used occasionally because it does not accurately represent the scope of welding tasks performed for most aerospace and aviation welding applications. AWS D17.1 even has a provision for welders to certify on a scrap part or mock up of a weld that is not represented well by a plain groove or fillet weld.
ASME section IX Boiler and Pressure Vessel Code has been around for a very long time, but AWS D17.1 is relatively new and was written to replace 2 old Mil standards… 1595a and 2219.
One thing both welding certification specifications have in common is that the test welds that are selected to be used for certification tests only qualify the welder for a range of positions, thicknesses, and joint types. No single test qualifies for all the possible material, thickness, positions, and joint types that are possible. That is why some welders hold a dozen or more certifications.
One main difference in welding tests for these 2 industries is that the initial welding test for Pipe welding jobs are largely done using low carbon steel or stainless steel. Other materials like inconel are sometimes used also but not nearly as much as carbon steel and stainless.
In the Aerospace and aviation industries, It is not uncommon for a welder to be tested on carbon or low alloy steels, stainless steels, nickel alloys, aluminum, magnesium, titanium, cobalt alloys, and even some refractory alloys like Niobium…with separate welding tests required for each material category.
One of the main differences in Tig welding pipe and tig welding aircraft or aerospace parts is in the thickness of material. In Aircraft welding , most everything is thinner. and that means smaller electrodes, smaller filler wire, smaller torches…and in Aircraft and Aviation tig welding, a 1/16″ rod is considered pretty big.