Cast iron welding

Cast iron welding is considered a special challenge and is one of the parade disciplines of welding.

If the carbon content in an iron-carbon alloy is ≥ 2.06%, it is considered cast iron. Cast iron is a collective term that covers many different iron-cast materials. What they all have in common is that the carbon is present in a “stably” precipitated form – as graphite – in the microstructure. In this respect, cast iron materials are not always easy to weld.

However, since it is precisely these difficulties that interest us at TM Lasertechnik, we have reproduced over 100-year-old processes in-house for this purpose. We were then able to transfer the knowledge gained from this into modern, automated laser welding processes and adapt them to today’s challenges. The result is very different process sequences with the laser or laser hybrid that are precisely tailored to the casting in question.

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We weld cast iron in globular and lamellar form!

Good to know:

Cast iron as a material

A distinction is made primarily between a lamellar (uniform / layered) and a globular (spherical) cast iron.

The properties of the various cast iron materials are essentially determined by their carbon content. This results in the form in which the carbon precipitates in the microstructure.

If it is present in the form of graphite flakes, for example, it is referred to as gray cast iron.

Difficulty in welding

The frequently asked question “Can cast iron be welded?” is not unjustified.

This is because, depending on the type, cast iron is considered in the technical literature to be either only conditionally weldable (carbon is present in globular form) or not weldable at all (carbon is present in lamellar form).

However, at TM Lasertechnik we have often been able to prove the opposite. There are conditions under which cast iron can also be welded in lamellar form.