With no two pieces of cast iron being the same there are obvious challenges to arc welding cast iron. Most cast iron welding is due to maintenance and cracked casting repairs. The main two methods of welding cast iron is by using oxy acetylene welding processes or using stick / arc welders.
Cast iron may be welded using a covered steel electrode, however this technique ought to be applied as an emergency solution solely. Whenever using any steel electrode, a contraction with the steel weld material, any carbon acquired in the cast iron from the weld metal, and also the hardness in the weld metal due to quick cooling down has to be considered. Steel shrinks a lot more than cast iron if ceded from the molten into a solid condition.
Each time a steel electrode is employed, that unequal shrinking can cause stresses in the joint following welding. Whenever a great quantity of filler metal is used on the joints, the actual cast iron may possibly fracture just back from the line of fusion unless of course precautionary measures are undertaken. To beat a lot of these complications, the prepared joints ought to be welded by way of depositing any weld metal in small stringed beads, 0.70 to 1.0 in. long (20.0 to 25.5 millimeters).
These are typically made sporadically and, in some instances, with the back-step and skip method. To help prevent hard spots, your arc ought to be struck in the V, rather than on the surface area on the base metal. Every brief length of weld metal employed on any joints ought to be carefully peened whilst hot using a modest ball peen hammer, plus permitted to cool prior to further weld metal being applied. This peening activity forges the actual metal and also minimizes any cooling down strains.
Cooling can also be assisted by covering the casting with a specialized cooling blanket or by covering the casting with sand. Arc welding cast iron is a slow process relying on diligent peening and cooling processes.