Hi
I have to weld a piece of mild steel to cast iron - its a pump impeller that a piece of it is broken and got lost. could you recommend what rods are suitable for the task?
Thanx.
Any good cast iron electrode will work well. If you were close to me i would mig weld it with cast iron mig wire but i don't think that wire is avail overseas...Bob
AAMM
Could you please let me know which mig wire do you use for such a weld? do you use argon/co2 mix or plain co2? any info you can provide - will be a great help.
As to rods - from what I found - there is the Ni55 which is recommended for cast iron, and then I've found a welding rod called GM which includes more copper and the manufacturer recommends it for welding mild steel to cast iron.
I was taught that there were 5 different types of rods that can be used for cast iron when I learnt the trade...nickel, nickel chrome, nickel iron, nickel bronze and low hydrogen. It all depends on the state of the casting as to what kind of result you'll achieve.
Poor casting which is porous, has inclusions or has spent time covered in oil can be a swine to weld. Rods may have moved on from my time, but if you have the skill gas welding was the first choice. But this in itself can be an art. If you go down the nickel based route then don't forget to peen it afterwards.