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Can I leave ferritic steel oxy-gas cut edges as they are?


Frequently asked questions

Gas cutting, if carried our correctly, will leave a smooth straight edge. It may have a glazed surface from the non-metallic substances in the steel which may prevent paint systems from adhering and a light grit blast or grinding can remove this effect. Poorly operated or maintained gas cutting systems may leave a rough or hard cut surface, possibly with grooves. This may (but should not!) be acceptable for simple non-structural applications, but for structural use the edge will require dressing to ensure that any cracks which may have occurred will be removed. Usually, gas cut edges which are to be incorporated in a welded joint can be left as cut as long as the cut is even because the edge is melted into the weld metal. The product standard or code may give gas cut edge requirements including allowable hardness and possibly grinding depths for removing the heat affected zone. As for welding, gas cutting should be carried out in accordance with an approved cutting procedure.

It is important to remember that in cases where the steel requires preheat for welding it may also require preheat for gas cutting to avoid cracks on the cut edge. The cut edges of ferritic alloy steels may also need to be ground back by some 1.5 to 2mm to ensure that any undesirable metallurgical structures, not sufficiently modified by the welding process, are removed. If not ground back it may be necessary to demonstrate that no degradation has taken place.

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