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Titanium Welding – Weld Colors Tell A Story If You’re Listening

Titanium welding colors can teach you something. Even if you don’t weld titanium, there is a cool trick where titanium welding colors help test the gas quality of your torch. Stay with me here and learn the trick.

Discoloration of titanium from the heat of welding is due to oxidation and the different colors are due to the varying thickness of the oxide layers.

The great thing about titanium weld colors is that they are predictable. In other words, we can determine what temperature the metal titanium reached when it was exposed to oxygen in the atmosphere.

The colors blue, purple, green, gray, and white occur at gradually higher temperatures.

There are also some intermediate colors and here is the progression.

The first titanium weld color is straw, followed by brown, then brownish blue, violet blue, green and blue, dull salmon pink, gray, and white oxide.

Some codes allow blue discoloration, but the best practice is to prevent titanium welds from fading beyond straw.

Titanium welds are often critical enough to maintain standards higher than the minimum allowed by a code.

But like I said at the beginning, even if you don’t need to weld titanium, you can use this information to test the shielding gas coming out of your tig torch.

Titanium begins to discolor around 500 degrees F. The hotter it gets without being protected by an inert gas like argon, the more it oxidizes and changes color starting with the straw and ending with the chalky white oxide.

But when protected by argon until it cools below 500 ° F, titanium will be shiny and silver even when heated beyond its melting point, which is roughly 3135 F, depending on the alloy grade.

What this means to you is that you can test the shielding gas coming out of your tig torch by simply puddling it and letting it cool and then evaluating the discolored titanium metal.

This is how you do it …

Set your tig welding machine to approximately 50 amps to weld titanium. Set your post-flow protection timer to 15 seconds. Hold the tig torch at a 90 degree angle with dead nuts to the titanium test piece and turn it on. Create a puddle approximately 1/4 “to 3/8”, keep the arc as short as the diameter of the tungsten used and wait about 7 seconds. Release pedal amperage control and hold torch still until weld and heated area cool completely … about 15 seconds.

If your argon is not contaminated, your electrode and the titanium pool will be completely silver.

There will be a circular area around the puddle weld where the argon sheath shielding protected the titanium, which is discolored. That’s fine as long as it’s symmetrical and at least as large as the inside diameter of the tig cup.

An oddly shaped halo of titanium weld colors too close to the weld could indicate a clogged diffuser in the gas lens nozzle body or other problem … and if the weld puddle and electrode are not silver shiny, you may have bad argon or a leak.

It is very important to know these kinds of things before doing a critical weld.