What is the difference between TIG welding and TIG welding as a root pass for pipes?
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This post was last edited by tanny1221 on 2009-10-22 at 14:20. What is the difference between TIG welding of pipes and using TIG welding for root pass? What are the performance differences between TIG welding of stainless steel pipes and using TIG welding for root pass?
TIG welding is generally used for the root pass on thicker pipes; the first layer is welded using TIG welding, and the surface is then smoothed with welding； For the thinner pipes, they are welded directly using TIG welding
There is no significant difference in terms of process between full TIG welding and TIG welding as a backing process; full TIG welding is suitable for thin-walled pipes with small diameters (usually DN50 and below, with a wall thickness of 4 mm), and its purpose is to ensure good quality and appearance of the weld root. When the pipe diameter is large and the wall thickness is thick, TIG welding should be used for the root pass while manual welding is used for the finish pass. The purpose of using manual welding for the finish pass is that, in cases of large pipe diameters, manual welding ensures better surface quality; it also offers higher productivity compared to TIG welding, with lower costs as well.
In my opinion, it’s probably just a difference in terminology; in pipe welding as I’ve experienced it, the inner core tube always requires TIG welding for the base layer and welding with a regular welder for the top layer.
In my opinion, it’s probably just a difference in terminology; in pipe welding as I’ve experienced it, the inner core tube always requires TIG welding for the base layer and welding with a regular welder for the top layer.
Personally, I think they are similar; however, TIG welding is suitable for thin-walled pipes with small diameters, while for pipes with larger diameters and thicker walls, TIG welding should be used for the root pass and manual welding for the finish pass
Tungsten inert gas welding is mainly used for pipes with a diameter of less than 4 inches (DN100). For larger pipes, it is generally necessary to use tungsten inert gas welding for the root pass and arc welding for the cover pass; this ensures the quality of the inner layer of the weld, improves production efficiency, and also results in better weld shape.
It’s just a matter of different terminology; TIG welding is used for pipes with smaller diameters, where welding is carried out directly using TIG welding. For pipes with larger diameters, TIG welding is used first as a base layer, followed by arc welding to complete the coating.
Large-diameter pipes are generally welded using a combination of argon welding and electric welding: argon arc welding is used for the root pass, followed by electric welding for the remaining parts. Smaller pipes can be fully welded using TIG welding.
Personally, I think TIG welding is used for pipes where it’s difficult to remove flux, slag, and other impurities, while manual welding offers higher efficiency, lower costs, and is easier to operate – these are the two main differences
The advantage of using TIG welding for the root pass is that it results in a good shape of the inner wall of the pipeline. For example, in oil transport pipelines, cleaning operations using cleaners are necessary after a few years of operation, and this approach helps to avoid blockages caused by debris. So generally, TIG welding is used for the root pass, while welding with an electric arc is used for the filling and finishing passes. As for thin-walled pipes with small diameters, TIG welding is used directly, as mentioned earlier, for pipes with a diameter of DN50 or less