Welding Of Cast Iron Slideshare. When welding cast-iron by the metallic arc process with cast-iron electrodes it is usually necessary to preheat the casting. During the welding of cast irons the iron immediately adjacent to the weld metal is heated to its fusion or melting point.
The tensile and compressive strength of cast iron of average quality is 150Nmm²and 600Nmm² resp. Its a good option to minimize the extreme heating and cooling of the electric welding processes and its easier to maintain the temperatures of the components with it. The formation of hard and brittle HAZ structures make cast irons particularly prone to HAZ cracking during post-weld cooling.
Opinions on the use of cast iron welding from the use of special filler rods to their complete unsuitability due to open arc such as TIG without the possibility of carbon migration.
Cast iron welding is done by using stick electrodes like Lincoln Ferrowed rods or it can be brazed by use of bronze filler rods. It is very important to understand the challenges involved in cast iron welding. Due to Carbons presence 2-4 the cast iron which is two times more than steel and it behaves as graphite characteristics and the properties of these type cast iron are prevalent as grey cast iron. Stick welding is the alternative method for welding cast iron where the electrode with flux is used.