The service conditions of die-casting die steel are divided into four categories, and the Tool Steel Committee of the American Institute for Metals has listed: cold work die steel, hot work die steel and plastic mold steel, and plastic die steel. Among them, cold work die steel is divided into 12 subcategories, hot work die steel 9 subcategories, plastic die steel 2 subcategories, plastic die steel 5 subcategories. The choice of materials for each sub-category depends on three main factors:
1. The complexity of size and shape.
2. The material to be processed.
3. Durability requirements or design life.
Cold work die steel is divided into five groups: W group, O group, A group, D group, S group:
1. Group W is water quenching tool steel, with 11 steel grades and 7 carbon tool steels, with a carbon content of 07%-1.3%
2. Group O is oil quenching and cold working die steel (commonly known as oil steel), with 4 steel grades and carbon content of 085%-1.55%
3. Group A is the air quenching alloy cold work die steel, with 9 steel grades and carbon content from 05%-2.25%
4. Group D is high-carbon and high-chromium cold work die steel, with 7 steel grades and a carbon content of 09%-2.5%
5. Group S is impact-resistant tool steel, with 7 steel grades and a carbon content of 04%-0.6%
There are also high-speed steels (HSS group) and ultra-high speed steels (SHSS group), cobalt-based cemented carbide and steel-bonded cemented carbide (HA group), powder steels and engineering ceramics (PIM group), carbon tungsten tool steels (F group), and special purpose tool steels (L group).