Alloy 20, primarily made up of nickel but containing iron, chromium, molybdenum and copper, is a metal that can be used for a variety of industrial purposes because of its ability to resist a number of acids. If you are welding with this metal, however, stay aware of the following pointers so that your weld turns out well.
Add Helium Gas
If you are like many welders and plan to use tungsten arc welding for your project, your first thought may be to tackle the weld with argon gas. However, it is important to note that, as a nickel alloy, Alloy 20 doesn’t conduct heat very well. Argon may be unable to cut through the alloy or may take much longer than other gases, such as helium, which heat up more quickly.
For better results, it’s a good idea to use a mixture of helium and argon gases to cut through the alloy. The combination will allow you to get a sharper weld point on the piece you’re working on.
Avoid a Small Gas Lens
It is a good idea to avoid small gas lenses while you work with this alloy. With a large lens, you will be better able to control the immediate environment around the weld point, ensuring that the gas will constantly flow, which can keep out contaminants and help you avoid air pockets. Because the weld is purer, you can worry less about how the weld will perform over time.
Keep Weld Current Low
Even if you are using a helium/argon mix on your weld, because the alloy is so thick, you might be tempted to turn up the temperature to get through it quickly. However, if you do that, you run the risk of causing the entire pipe to weaken. That’s because as the metals melt and turn to liquid, heat that is too high may even cause some of the liquid metals to evaporate. Because in that case the pipe no longer has the same chemical makeup, it is weaker than other portions of pipe. As a result, the pipe might be more likely to rust or buckle.
Instead, make a conscious decision to keep the tungsten temperature low as you weld. Patience will give you good results and preserve the integrity of the pipe.
With the pointers in this article, you can be more confident about welding with Alloy 20. If you need assistance, talk to an expert (such as one from Tiger Metals, Inc.) who can help you with your project.