If you are a seasoned welder then you must be aware that one of the most challenging projects that you can undertake is cast iron TIG welding. Even experts and experienced welders find this to be very challenging. Cast iron has a high carbon content, it is usually between 3 to 8 percent. If you know anything about metals, that is a lot of carbon. The high carbon content of cast iron accounts for the characteristic brittleness and the difficulty that one encounters when welding. If you are really bent on welding with this material then you have to have exact controls when it comes to temperature and the process. You have to be careful so that the cast iron will not start cracking once you begin the process of welding it.
How to Prepare- Using a grinder you have to make sure that you are able to remove all rust and dust particles on the surface that you are planning on joining. Achieving a smooth surface can contribute to the quality of your weld. Before you start welding you need to preheat the materials to a temperature of up to 550 degrees Fahrenheit. This is needed because the material may start to crack the moment you start welding if the material is cold. If you will be doing a lot of welding to the material, then you have to keep on heating it as you are working, to make up for the cooling down. Remember that cast iron is a material that is highly sensitive to changes in the temperature.
The Welding Process- Aluminum bronze makes a very good filler material. If the material will be undergoing a lot of thermal changes then you can use nickel. Avoid too much heat on the arc by sticking to short welds instead of one constant long weld. While the weld is still red hot, you can use a little hammer to strike it. That will help relieve the stress on the weld. Use low current weld only to avoid stress from occurring.
Cooling Down- The cooling period is important when you are welding cast iron material. It is important that you allow it to cool slowly after welding. Cooling down quickly can cause the cast iron to harden and turn brittle and that is something that you do not want on your material.When your cast iron material becomes brittle there is little that you can do with it. The crucial period after the actual welding would 12 to 24 hours. You can either cover it up with insulating materials like sand or keep it in an oven while bringing down the heat gradually.
While TIG welding cast iron is a difficult undertaking it can be dome with the right tools, materials, and knowledge. If you are a skilled welder already you can certainly pull it off, just by using the steps that we have given here. Just keep these things in mind and you are sure to get the hang of the process in no time at all.