Welding Cast Iron by TIG and MIG

Stick Welding and Brazing are not only the two methods to weld or repair Cast Iron. TIG and MIG welding can also be successfully used to weld-repair cast iron jobs.

Welding Cast Iron by TIG welding is although limited but using MIG welding is widely adapted in the industries.

This article explains step-by-step guidelines on How to Successfully Carry out the welding of Cast Iron using TIG and MIG welding.

Welding Cast Iron by TIG Welding

First of all, remember that Cast Iron comes in a lot of variants, and out of those variants weldability of same can vary for old and new cast iron materials.

Read more: Best Cast Iron Welding Rod.

TIG welding rods for cast iron are not classified in any AWS Specification. For example, Stick Welding cast iron welding rods (such as Nickel 99 and Nickel 55) are classified in AWS A5.15 specification, but for TIG rods there are no such classification system.

Welding Cast Iron by TIG

Nevertheless, some welding consumable manufacturers have mastered Cast Iron TIG welding rods which you can use to carry out cast Iron TIG Welding.

Blue Demon ERNi55 and ERNi99 are two best options for Cast Iron TIG welding rods that gives machinable and satisafactorily welds.

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For TIG welding cast iron, you need to use 100% pure argon welding gas shielding to protect the molten pool from oxidation.

Techalloy 55 and Techalloy 99 (ERNi-CI) by Lincoln can be purchased in TIG and MIG wires. Even you can buy MIG Techalloy 99 and use it with TIG Welding without any issues.-

  • When TIG welding cast iron apply a preheat temperature of 350°F (175°C) and maintain this preheat throughout the welding.
  • Apply pinning on red hot metal to avoid cracking and relieve the stresses.
  • If you will not apply preheat during TIG welding cast iron, you can face cracking in the weld toe or underbead cracks.
  • If TIG welding does not work for your cast iron, another best option is to try Cast Iron Brazing.

Welding Cast Iron by MIG Welding

Cast iron is a difficult metal to weld, but it can be done using the MIG welding process. In fact, lot of big casting repairs are usually carried out using MIG welding.

To MIG weld cast iron, You need to use a special type of filler wire that is made for welding cast iron such as ERNiFe-CI (Nickel 55) or ERNi-CI (Nickel 99).

Equipment setup mig mag

For MIG welding cast iron, you need to use (75-25 Welding gas) 75 argon-25 CO2 welding gas shielding to protect the molten pool from oxidation.

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Other Methods for Cast Iron Welding

  • Cast Iron can also be successfully welded using Stick Welding and Brazing. For the repair of cast iron, stick welding is a good option.

Two most common cast iron stick welding rods are:

  1. Nickel 55 and
  2. Nickel 99.

Check out my article on detailed guidelines for Cast Iron welding by Stick Welding.

  • You can also use Brazing to repair and weld difficult-to-weld cast irons. Brazing works by without melting the cast iron.

Different brazing rods are available in market for Cast Iron Brazing. Check out my article on Cast Iron Brazing in details.

One other option is to go for Cast Iron Cold repair. Cold repair of cast iron can be carried out using JB Weld.

JB Weld is the perfect solution for repairing cracked or broken cast iron. It is strong, durable and easy to use.

Simply mix the two part epoxy, apply it to the surface and let it cure. Once cured, JB Weld will be as strong as new and will last for years.

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