In the past, most welders would never even think about TIG welding cast iron due to the unpredictability of such repairs but times have changed and it can now be done albeit with utmost care. Welding cast iron was difficult because iron contains carbon which makes it extremely hard and suffers from cracking problems as the cast iron is brittle. Instead of bending when heated, it breaks.
Nickel rods, also called Ni rods are the most preferred and popular in welding rods for the TIG welding cast iron. Some of the reasons this is considered the perfect choice for cast iron welding include:
The carbon content does not cause unwarranted hardening of the weld deposit. The metal cannot crack easily near the weld are because the weld metal used doesn’t have shrinkage stresses. The welding rods, in this case aluminum bronze, are strong as the steel and ensure that the welded area holds and the TIG weld happens as planned. When welded using AC, the aluminium bronze rods do not all get diluted from the iron metal because they wet easily and thus can flow with ease! In terms of cost, aluminum bronze welding rods are cheaper than the Nickel rods which can make TIG welding cast iron procedure pocket friendly. TIG welding cast iron requires absolute concentration and careful temperature monitoring to limit the possibility of cracks in the brittle cast iron. The process to do this effectively follows:
Make sure the surface or weld location thoroughly cleaned to get rid of impurities like dust and rust. A clean surface will aid in ensuring a strong weld formation. The parts should then be pre-heated to prevent a possibility of the cast iron cracking. If the procedure is projected to take the longer then the cast iron should continue to be heated, at a constant rate during this duration, since it is very sensitive to temperature shifts.
For the TIG welding cast iron procedure, select the aluminum bronze if the iron being welded will not experience further heating during its use afterwards but if it will, go with the Nickel filler rods as they can withstand heat, example of this is engines. The use of low current is recommended to discourage residual pressure and stress from building up. Do many short welds instead of a continuous one to regulate the temperature then hit the weld with a hammer to relieve the accumulating pressure?
After completing the welding, the iron should be left to cool down slowly to prevent the hardening. To achieve this efficiently, the part should be put in an oven then the temperature can be lowered slowly as time goes by. This constitutes a perfect TIG welding cast iron mission.
Clean Metal Surface
The main TIG welding tip demands that the metal being welded should be free from paint, rust or any other barrier. Bad weather, especially windy conditions, are not favorable for efficient TIG welding.TIG welding rods contain silicon and other deoxidizers that remove impurities from the weld area so do not use any other rods as this will expose you as being unprofessional.
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