Cast Iron Electrode
Cast irons are a family of iron-carbon alloys. Their high carbon content (usually 2-4%) determines the hardness of cast iron. However, this difficulty is achieved at the expense of plasticity loss. It is less ductile than steel or wrought iron. Heating and cooling cycles during welding cause the metal to expand and contract, causing tensile stress. Cast iron does not stretch or deform when heated or pressed - instead, they crack, making them difficult to weld. This feature can be improved by adding different alloys.
Electrode Selection
If the part is to be machined after welding, a nickel-type electrode will be required. Use Lincoln Softweld® 99Ni stick electrode for single pass, high dilution welds. Softweld 55 Ni is preferred for multiple pass welds. Sometimes, root passes are put in with Softweld 99 Ni, followed by fill passes with Softweld 55 Ni. For welds where machining is not required, and where the weld is expected to rust like the cast iron, Lincoln Ferroweld® stick electrode can be used.
