What Kind of Rod Is Compatible With Cast Iron & Mild Steel?

Welding Cast Iron

• Cast iron is a challenging material to attempt to repair because it will either break or harden when welded. It requires special materials and techniques for successful joining. Generally, pre-heating is recommended, bringing the piece to be welded to up to 900 degrees Fahrenheit in an oven, according to the LockNStitch website. Post-heating after welding may also help to reduce cracking problems in cast iron.

Welding Mild Steel

• Mild steel is much easier to weld and can be joined with a variety of rod types, including 6010, 6011, 6013, 7018 or 7024 low hydrogen rods, according to the RodOvens website. Mild steel rods, silicon bronze, nickel or a number of alloys can all be used on mild steel in either plate or sheet metal forms. When welding mild steel to less weldable metals, however, you will be limited by the needs of the more difficult material.

Nickel Rods

• Nickel rod is the type most frequently recommended for use in welding cast iron parts. These rods are more expensive than the other commonly used rods but provide the right composition to create joints on cast iron materials. Nickel alloyed with other materials are also used, such as Nickel #55 and #99, according to the Brazing website.

Bronze Rods

• Bronze can also be used to weld cast iron, though many people are not familiar with its use. Bronze is similar to cast iron in hardness and metal-to-metal wear resistance. Though cast iron has more tensile strength than bronze, bronze still makes an acceptable metal for joining cast iron to other materials.

Copper Alloy Rods

• Copper-zinc and other alloys are sometimes used for welding cast iron and steel, particularly in brazing operations. Copper-zinc is often used with oxyacetylene welding. It improves strength and corrosion resistance in the weld.

Low Carbon Rods

• Low carbon rods are often recommended for working with cast iron and mild steel, but this type of rod can give variable results that cannot withstand machining or other operations on the material after welding. Low fuming bronze bare is a general purpose rod that can be used for a variety of different materials, including for welding cast iron, mild steel and many alloys.