Ever since 2002, SSAB have marketed Toolox® 44, as a plate product for tooling applications. Now Toolox is also available as round bar with the same attractive properties as in plate. Toolox bars are stocked in peeled execution.
The principal characteristic of Toolox 44 as supplied is its very high strength and hardness. Typical levels are 1 450 MPa for tensile strength and 440 HB for hardness. The efficiency of quenching during hardening is such that the material in the bar centre has almost the same hardness as that close to the surface.
In spite of its high strength, the steel is comparatively low-alloyed which means that machinability and weldability remain acceptable. Furthermore, considering the high hardness level, Toolox has quite good impact toughness.
The high strength of Toolox can be used to good effect to increase the fatigue resistance of a component. Alternatively, the weight can be reduced without loss of performance. Furthermore, the high level of cleanliness (freedom from harmful non-metallic inclusions), derived from a careful process control in steelmaking, contributes to the favourable fatigue properties.
Toolox responds well to nitriding surface treatment, which confers a surface layer with even higher hardness, low friction and some degree of resistance to corrosion.