Welding cast steel - is that possible?

With cast steel, it always comes back to doubt whether it is even weldable, and if so, with what methods it is best welded. The requirements for welding and the differences between individual cast steel grades are explained in detail in this article.

cast steel

Steel casting refers to those steel grades that are used as starting material to produce castings directly from the steel produced.

Carbon content

Typical for cast steel are carbon contents of up to 0.5% - so there is no sweat suitability for all cast steel grades from the outset. The limit for good weldability is at carbon levels of up to 0.22% or equivalent carbon equivalent for higher alloy steels.

In principle, however, most varieties are quite easily weldable in practice.

DIN regulations for welding cast steel

According to DIN DIN 1559, which applies to cast steel, welding of cast steel workpieces is generally permitted. However, it must always be adapted to the technical and material properties of the work piece material. For welding steel castings, appropriate welding procedure tests must also be carried out (DIN EN 288).

Different welding suitability and preparatory work

For all austenitic cast steel grades, it is not necessary to pre-heat the workpiece, except for material number 1.4446. Here, depending on the geometry and the thickness of the workpiece between 20° C and 100° C must be preheated.

For all fully austenitic varieties (this is a separate variety, independent of austenitic varieties!), Preheating must also take place between 20° C and 100° C, and the same applies to austenitic-ferritic varieties.

For martensitic cast steel grades, the need for preheating and the temperature ranges for preheating are very different and each depends on the particular cast steel grade. Preheating is not required for material numbers 1.4405 and 1.4411, however, for material number 1.4011 pre-heating to 250° C to 300° C is required before welding. Here you must always look up under the respective material number.

Also, the danger of possible intercrystalline corrosion must always be taken into consideration, in the heat-affected zone, and possibly even in the remaining material.

Tips & Tricks

It is also important to observe the order of the individual works. For example, a coating can be done before or after welding, but this has an effect on the tempering or relaxing of the steel and the temperatures used there. Austenitic varieties may in principle only be welded in the quenched state.

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