TIP TIG & ARC Weld Process ComparisonS BY EM CRAIG
To truly understand the benefits of a weld process, the weld shop needs to be aware of the positive feature benefits of that process, and especially how it competes with the well established arc weld processes.
A Comparison of the Traditional Arc Weld Processes, MIG - Flux Cored - GTAW and the Hot Wire Process, Versus TIP TIG.
As weld shops are aware, for many decades there has been TWO Semi-automated arc weld processes, MIG – Flux Cored, that account for approx 85 – 90% of all welds produced daily. However when the highest quality manual welds were requited, the GTAW process that lacks the semi-automated capability, would usually be the first choice. And when the best automated all position code quality weld was the requirement, the Hot Wire TIG process would be considered.
In N. America till 2009, weld shop never had a semi-automated process highly suited to meet all position, code quality welds that would not require weld re-work. TIP TIG is a semi-automated / automated arc weld process capable of providing the highest all position, arc weld energy in an inert atmosphere, while at the same time enabling the lowest welded part heat.
Think carefully about the highest weld energy generated in an inert atmosphere, along with the lowest welded part heat attributes. Give consideration to how the easy to use, all position TIP TIG attributes, not only benefit both the welds, and with all metals, the after weld, metallurgical properties. Think about those weld / part benefits on common alloys such as Stainless, Duplex, Hastelloy, and Inconel. These and most of other alloy steels and alloys, will all be sensitive to weld heat. All welds will have fusion, porosity, cracks, and weld solidification and weld fume concerns. All will have welded part mechanical and corrosion concerns. These are concerns that will no longer be an issue with either the semi-automated or automated TIP TIG welds.
AC/DC TIG in Comparison to TIP TIG
Developed when I was born in the 1940s, the AC/DC TIG process has always been the arc process that provided the best possible weld quality on all weldable metals. However, this process, which was poorly suited for automated welds, has also created many manual weld concerns.
- Highest Skills: When weld shops use TIG, they are using a process that requires the highest welder skills, and the skills & practices used will often vary from one welder to another, which influences weld quality uniformity.
- Lowest Deposition: Weld shops realize with TIG that they will be producing the lowest arc weld deposition rates that influence weld labor costs and weld travel rates.
- High Part Heat: While welders are using DCEN polarity, the polarity benefits are lost on the parts welded as a result of the very low weld speeds utilized.
Pulsed MIG in Comparison to TIP TIG
No matter how costly and sophisticated the electronics are in a Pulsed MIG power source, Pulsed MIG will never provide the weld quality or weld capability of the TIP TIG process.
- Too much-welded part heat: Pulsed MIG uses Reverse Polarity, and the concentrated plasma heat around the tip of the welding wire will always create welds with larger heat affected zones than welds with TIP TIG.
- Too little weld energy: Arc temperatures are much lower in a MIG weld than a TIP TIG weld, and with a Pulsed MIG weld, there is often not sufficient energy in the pulsed MIG weld for the weld mass-produced and the weld travel rates enabled. This is the reason why on X-Ray code quality, all position welds on parts > 5 mm thick will often reveal a lack of fusion or excess porosity.
- Too Reactive: Pulsed MIG requires a reactive gas mix that adds to weld oxidation and porosity. TIP TIG does not.
Hot Wire TIG in Comparison to TIP TIG
Add approx. 80 to 120 amps of current to a continuous fed wire that’s fed into a TIG arc, and you have the Hot Wire TIG process. The additional wire energy allows the wire to melt more rapidly, enabling more wire to be delivered, which then allows more weld current, which increases the plasma energy and density. So why is the Hot Wire TIG process mostly utilized with automated welds and poorly suited as a manual semi-automated arc weld process?
Two key issue with low to moderate current Hot Wire TIG applications are:
Even with high current Hot Wire applications, the arc length needs to be fixed or costly automated arc length adjustment is necessary. To find out what was required to change Hot Wire TIG into a process suited to manual welds, and an automated process no longer arc length sensitive, you may want to…
Flux Cored Vs. TIP TIG
Weld shops have limited arc weld process choices for all position code quality weld, SMAW, (stick), DC TIG, Pulsed MIG & the Gas Shielded Flux Cored process. With SMAW and well-qualified welders, there can never be a guarantee for the internal weld quality, high welder skills are required, and weld fumes always issue. With TIG, you will grow grey hair welding a few inches of good quality weld. The highly overrated Pulsed MIG process when used on all position steel and alloys welds on parts > 5 mm, will likely have weld fusion or porosity issues with excess weld heat into the parts. As you can see on the right even with optimum weld settings and weld practices, with the erratic flux to metal mix, with flux-cored, the welder will produce welds that often will reveal, trapped slag, worm tracks, excess porosity, lack of weld fusion, spatter, large heat-affected zones and always weld fume concerns…