1.2344 Tool Steel is a versatile chromium-molybdenum hot work steel that is widely used in hot work and cold work tooling applications. The hot hardness (hot strength) of 1.2344 resists thermal fatigue cracking which occurs as a result of cyclic heating and cooling cycles in hot work tooling applications. Because of its excellent combination of high toughness and resistance to thermal fatigue cracking 1.2344 is used for more hot work tooling applications than any other tool steel.

Because of its high toughness and very good stability in heat treatment, 1.2344 is also used in a variety of cold work tooling applications. In these applications, 1.2344 provides better hardenability (through hardening in large section thicknesses) and better wear resistance than common alloy steels such as 4140.