The Varying Personalities of Exotics and Alloy Steels FEATURED STORY

An Interview With Travis Field – Rig Welder and Welding Supervisor Part Two of Two

Did you know that every metal has its own unique personality, nuances, quirks, and mannerisms? Did you know that a welder should be a kind of ‘metal-psychiatrist’ to be able to do the welding job correctly? This is something that Travis Field of Legion Piping Fabricators, has become acutely aware of during his career.

In part two of this interview, Stainless Steel World Americas was happy to speak with Field about the psychological approach he applies to welding, and his excitement for passing on knowledge and experiences to a new generation of Welders.

By Editorial Team

Welding Procedures

When it comes to welding different metals, there are three very distinct welding techniques – including variations and movements of a technique, as well.

On carbon steel and chrome of 1.25% and 2.25%, as the material flows and is washed out with minimal effort, and as there is no internal purge, the best technique to use for position welding is a continuous feed technique. If filler metal is added then removed from the weld puddle, the tip of the filler metal will oxidize in the presence of the open atmosphere inside the pipe. When reintroducing the oxidized tip of the filler metal into the weld puddle, the weld puddle will become very sluggish. It should be noted that the formation of oxides effect and influence the weld puddle in different ways, including the oxides of different metals themselves behaving very differently. For roll welding, continuous feed or lay wire technique is effective.

Stainless steel 304L, which is a very common stainless alloy, can be welded with a continuous feed technique with good control. Simply use a finer side to side movement to keep the overall puddle in a relatively liquid state with good puddle movement. “Stainless is actually very versatile; you can use different techniques with great control and success. Stainless steel is very complimentary of the lay wire technique for roll welding. You can form a very aesthetic root pass internally inside the pipe simply by washing over top the filler metal that is situated atop the bevel tips and sinking the puddle down through the gap.”

When you start to get into 316 stainless steels, more sluggish stainless alloys, including duplex, super duplex, nickel alloys such as Hastelloy, Monel, Inconel, and variations including Titanium, the welder will have immense and great success when using the dab technique or the break surface tension technique. Filler metal can be internally fed inside the pipe on position welding, and often for roll welding, the filler metal will be held outside of the pipe (same as lay wire for carbon, chrome and stainless steel alloys) but consumed via one of two techniques.

“When using a dab technique, your line of sight will be in a position where you can see both the internal and external leading edge of the weld puddle, as it is being pulled towards your vision. The TIG torch on the outside of the pipe will move to the leading edge of the weld puddle to open a keyhole. The outside leading edge will turn to a liquid as it is closest to the heat source of the tungsten, with the internal leading edge turning to a liquid a split second later. Take the filler metal which is a solid mass, and simply add the tip of the filler metal to the liquid, internal leading edge of the weld puddle, and now pull away. This is ‘dabbing’,” Field explains. “Essentially, the mechanics of this particular technique is that the weld puddle is a liquid mass, and the filler metal is a solid mass. You have a given amount of energy from the TIG torch, which is keeping the weld puddle as a liquid, and once the solid mass of the filler metal is added in, and removed, there is just enough energy to break down and remove some material from the solid mass of the filler metal to be consumed into the weld puddle. This is not enough energy to keep the entirety of the weld puddle as a liquid, and therefore the tail end of the weld puddle will thus turn to a solid mass. If welding current is increased, then there will be too much energy, thus keeping the weld puddle as a liquid. When the solid mass of the filler metal is added momentarily and then removed, the weld puddle will only then remove metal from the filler and become larger and more agitated. In contrast, if the welding current is decreased, there will not be enough energy to keep the welding puddle as a liquid. In this case, when the solid mass of the filler metal is added momentarily, the weld puddle will simply turn to a solid because there is not enough energy to break down the solid mass of the filler metal and partially remain liquid as a weld puddle.”

When talking about the break surface tension technique, this technique has the very same mechanics and structure as the dabbing technique, however the distinct difference is simply, when you add the solid mass of the filler metal to the liquid weld puddle, you allow the filler metal to remain in place and it will be the weld puddle itself which will melt and pull away enough material from the filler, breaking the surface tension in the process. “In short, with dabbing, the filler metal being removed breaks the surface tension, while with this latter technique, the weld puddle pulls away, thus breaking the surface tension.”

A common weld test used to trip welders up is to set up three individual pipe test coupons of different material. Stainless 317 is one pipe setup, Inconel 625 is another pipe setup, and 9% chrome is the last pipe setup. The stainless will be quite runny while the chrome will be very sluggish. The Inconel will fall in the middle of the two. Dab technique and break surface tension technique will be used to weld these materials. “If set to a lower welding current, you can take advantage of dabbing. If current is slightly higher, you can use break surface tension technique, and what it comes down to realistically is control of the weld puddle using the solid mass of the filler metal as a heat sink, as means to chill out and lower the energy used to keep the weld puddle as a liquid, and manipulate its rate of solidification and liquification. The filler metal is a solid, the weld puddle is a liquid and it takes a given amount of energy to turn a solid into a liquid, as well a given amount of energy to keep a liquid as a liquid, otherwise it will turn into a solid. With this knowledge, you will be able to manipulate the welding puddle as desired.”

Travis Field's first time in Houston, TX, on the set of Weldtube showing how to weld Titanium.
One of Travis Field's welding coupons in Legion Piping Fabricators.

Ensuring Proper Knowledge Transfer

What role will Field have in training new talent in the welding industry? “In neural linguistics programming, when you are dealing with a technique or pattern of movements, you need to break them down into their intricate mechanic parts so that everything is simplified and easy to understand,” Field says. “This way, you can see a working relationship of how everything comes together.”

He continues, “I will be working along side welders when I am in Houston, TX as a Welding Supervisor. I plan to first talk about the welding techniques and teach them the pattern of my movements, explaining what I am looking for and paying attention to. I will have them take over, allowing them a familiarity with the metal and helping them to gain some confidence. I will have more resources available to me when down in Texas, including being able to send the welder to the South Coast Welding Academy for training. If a welder is struggling, I will help them out, whether I need to watch them rerun a spot, fix a spot, look over an X-ray with them, help them with a repair, or help them work on techniques or different metals. Welders should be comfortable confiding in a supervisor without the worry that they may lose opportunities.”

Final Words

Becoming a welder changed Travis Field’s life. He concludes, “I found something that I was really great at. I have made some really good connections and built great relationships working and travelling throughout my career. I am excited to see what new opportunities await!”

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Sara Mathov is a feature editor contributing to Valve World Americas, Stainless steel World Americas and other related print & online media.