Although you may be an experienced welder, you may be faced with your first welding project involving alloy 20 pipes. Because these are constructed of highly durable nickel-based metal, welding them can present some challenges. Below are four tips that will help you get through your first time.
Use A Mixture Of Argon And Helium Gases
Because you will be using gas tungsten arc welding, or GTAW, when working on the pipes, your primary gas should be argon. However, since nickel alloy is a low conductor of heat, argon alone may not be hot enough to melt or cut the material.
In order to turn up the heat, use a combination of argon and helium gases. Helium is more combustible than argon, so it will increase the temperature. This enables you to heat up the pipes faster, increasing your chances of having a cleaner weld point.
Use A Large Gas Lens
While welding the nickel alloy, use a large gas lens to ensure a smoother, more even distribution of gas while you are working. Using the largest cup available that fits above your weld point creates a stable envelope of gas around the metal. It also creates an even, steady flow of your shielding gas.
Using a large gas lens decreases the risk of having a rough weld point. Also, having a stable flow of gas decreases the chances of contaminants, making your weld purer and keeping air pockets out of it. The purer the weld, the less likely it will break when exposed to changes in temperature and moisture, such as sudden cold snaps or ice storms.
Take Your Time While Welding
Once you start welding on a piece of pipe, take your time. Do not try to rush the job because it will take you longer to cut through nickel alloy than other materials such as galvanized steel or copper.
Because of its low heat conductivity level, the nickel will have a thicker puddle as it melts, even under high heat. To get through the thickness of the puddle, going slow is essential so you do not end up with an uneven or defective weld.
Do Not Increase Your Weld Current
Welding alloy 20 pipes can be a slow process. As a result, you may be tempted to turn up the weld current to help you slice through the thick nickel puddle faster. However, you may want to think twice about doing so.
When nickel alloy is overheated, the other elements within the metal are evaporated. Some of these prevent the pipes from rusting or corroding, such as chromium or stainless steel. If these are removed, the weld point and pipes surrounding it become weaker.
Not only does this increase the chance of breakage at the point, but that section of pipe will not last as long. This is because it is no longer protected by the other elements, causing it to break down quicker. This eventually leads to rust and corrosion, making replacing the pipe necessary sooner.
When welding the alloy, use low to moderate current through your tungsten and, as stated in the previous section, take your time. The low current and slow-moving rhythm will keep the other elements from evaporating, giving you a stronger, longer-lasting weld point.
Heeding the above tips can help increase your chances of a successful weld. However, if you get stuck or are having problems, you may want to seek out the assistance of a mentor who is experienced with welding alloy 20 pipes. They may be able to give you some pointers and show you the proper rhythm and technique. For more information about alley 20, visit websites like http://www.jamesduva.com/.