INFLUENCE OF BORONISING ON MECHANICAL PROPERTIES OF EN-C35E STEEL

Carbon steel was boronised in a salt bath containing calcined borax, boric acid and ferrosilicon at 850 C or 950 C for 2-8 h in an argon atmosphere. The resulting surface hardness and fracture toughness were determined by indentation testing. The hardness was dependent upon the boronising time and temperature, values almost 8 times that of the steel substrate being achieved. Metallographic studies and XRD measurements confirmed the formation of single-type Fe2B layers. The surface had a columnar morphology, with good bonding to the substrate. 5 refs.