Cast Iron is a challenging material for Welding, even for the experienced welder. So how to select the best Welding Rod for Cast Iron Welding to ease your troubles.
The reason for difficulty in Cast Iron Welding is– Different type of cast Irons and their different metallurgy that affects the weldability, its brittle & hard microstructure and presence of high carbon.
Related Reading: Types of Cast Irons, Identification & their Welding
Best Cast Iron Welding Rods
Best Welding Rod to use for Cast Iron are one that resist cracking during welding. The best cast iron welding rods are Nickel base welding rods such as Nickel 55 and Nickel 99.
Nickel 99 Cast Iron Welding Rod
Nickel 99 (AWS specification & Classification: A5.15- ENi-CI) is a high nickel base cast iron rod. ENi-CI rod contains up to 2% Carbon, 2.5% Manganese, 4% Silicon, 8% Iron and a minimum of 85% Nickel.
Nickel-55 cast iron welding rod can be used for welding of gray cast iron, cast iron to carbon steel, cast iron to stainless steel or any ferrous & non-ferrous metals.
Nickel 99 rods are having good machinability but lower strength compared to Nickel 55 cast iron welding rods.
Complete chemical composition of ENi-CI (Nickel 99) Cast Iron Welding rod is given in the below table:
Nickel 55 Cast Iron Welding Rod
Nickel 55 (AWS specification & Classification: A5.15- ENiFe-CI) is a Iron-nickel base cast iron rod. ENiFe-CI rod contains up to 2% Carbon, 2.5% Manganese, 4% Silicon, 45- 85% Nickel and balance Iron (Fe).
Nickel 55 cast iron welding rod can be used for welding of nodular cast iron, Gray Cast Iron, cast iron to carbon steel, cast iron to stainless steel or any ferrous & non-ferrous metals. They can also be used for welding of cast iron with higher phosphorus level.
ENiFe-CI-A is a improved version of Nickel 55 welding rod with higher amount of silicon allowing better slag coverage and characteristics.
The chemical composition of Nickel 55 or ENiFe-CI (SFA 5.15) cast iron welding rod is given in the below table:
Should you use E7018 or E6013 Welding Rod for Cast Iron Welding?
No, you should not use E7018 or E6013 Welding rod for cast iron welding as it is not crack resistant alike Nickel 99 or Nickel 55 Rod.
Many people who say E7018 or E6013 can be used for Cast Iron is actually use it on Cast Steel (Carbon steel but in casting form). This cast steel is readily weldable with mild steel rods such as E6013 or E7018.
Welding Cast Iron with E7018 is not advised unless there are no other options available. E7018 may able to produce a weld pool but will lack in good fusion with cast iron material as it does not have sufficient Nickel to hold excess carbon from cast iron.
Stick Welding Polarity for Cast Iron Welding- AC or DC?
You can use Cast Iron Welding rods with AC or DCEP polarity. Welding using DCEP polarity with low welding amperage (Current) that gives good weld bead profile, good fusion and smooth welding operation.
What is the best Welding Process or way to Weld Cast Iron?
The best welding process method or way to weld Cast Iron is Stick Welding (SMAW) using Nickel base welding rods such as Nickel 55 or Nickel 99. These welding rods gives good weld fusion, weld ductility and crack resistance welds.
Best way to clean Cast Iron before Welding
The best and effective way to clean cast iron before welding is by heating it to 750°F (400°C). Heating Cast iron before welding at this temperature will remove all grease, oils, dirt or any other impurities (e.g., lead) that can reduce the cast iron weldability. At 750°F (400°C) temperature, these impurities will be flushed out in gaseous form.
Best Welding rod for Cast Iron to Mild Steel
The best stick welding rod for welding of Cast Iron to Mild steel is Nickel 55 (ENiFe-CI or ENiFe-CIA). Nickel 55 gives a strong, machinable and ductile weld joint between the cast iron and mild steel material.
What is Cast Iron Electrode Number & Name
The mostly used Cast Iron Welding electrodes with their numbers and Name are:
- Nickel 55: ENiFe-CI (SFA 5.15)
- Nickel 99: (ENi-CI) (SFA 5.15)