The continuous heat treatment of tool steel is applied to low- or medium-alloyed carbon steel strips as well as martensitic stainless steels. The described lines produce high-quality strip with respect to uniform structure, flatness, and bright surface finish. Steel grades with 0.4 to 1.2% C, low and high alloyed, can be processed.
Strip dimensions range between 10 to 750 mm (0.4 to 29.5 in.) wide and 0.05 to 4 mm (0.002 to 0.16 in.) thick. High quenching rates are necessary, especially for plain carbon steels. Cooling gradients of up to 600 K/s are possible in a molten lead-bismuth quench. Because two-stage quenching technology provides considerable advantages over quenching in oil, this method has been adopted worldwide. It is also possible to achieve isothermal transformation to bainite and pearlite using a molten metal quench, so this type of hardening and tempering line is extremely versatile.
For more information, click on the link below (subscription required). Then scroll to Figure 9. R Schneider; R. Mesquita; W Schützenhöfer, Distortion in Tool Steels, ASM International, 2014 https://doi.org/10.31399/asm.hb.v04d.a0005958
