5. Ingot processing

Transformation ranges may vary according to the means available, but all ranges must be guided by precautions dictated by the particular characteristics of tool steels: often reduced forgeability, sensitivity to tapping, tendency for carbides to coalesce and grain coarsening.

• Ingot heating cycles must be carefully determined and, above all, adhered to. As the thermal conductivity of such steels is generally greatly reduced by the alloying elements (with the exception of cobalt) and in particular by chromium, silicon, vanadium and nickel, heating and cooling must often be slow (speed below 150°C/h), especially heating, with steps to equalize the temperature throughout the mass. In the case of ledeburite chromium steels and high-speed steels, annealing of the ingot is recommended to avoid any risk of tapping during this heating operation....