Laser surface alloying of iron and 1C–1–4Cr steel with carbon

Abstract

An investigation is reported of the introduction of carbon into a pure iron and into a 1C-1·4Cr steel (S 135) by means of laser surface alloying. The procedure involved precoating the specimen surfaces with Dag graphite; successive laser surface-melting treatments (up to 12) were given, re-applying the graphite coatings between each treatment. Alloying was carried out both with shallow melt zones and with ‘keyhole’ zones. Substantial degrees of carbon alloying were achieved, ranging from hypo- to hypereutectic levels; the maximum obtained was ∼6%C. In the hypereutectic zones substantial cracking and porosity were encountered. The white iron structures obtained were observed by optical, scanning electron, and transmission electron microscopy.