scope:

Material Description. This material specification applies to low to medium alloy modified American Iron and Steel Institute (AISI) AISI P20 Tool Steel, as defined in ASTM A681, produced through various melting, forging, and heat treatment manufacturing processes.

Symbols. Not applicable.

Applicability. Modified AISI P20 Tool Steel is used in the construction of cavity and core tooling used for the thermoplastic injection molding. GM Tool Steel Grades in this standard are specified by surface hardness, hardenability, microstructure, chemistry, physical properties, and quality requirements to achieve a balance of machinability, thermal conductivity, fracture toughness, corrosion resistance, weldability, wear resistance, ability to polish, ability to etch, and core strength which are all critical characteristics of injection mold tools.

This standard addresses Steel Supplier and Material Requirements for modified AISI P20 Tool Steel and are part of the Steel Supplier Approval Process. After successful completion of the submission per A1 in Appendix A, and GM approval, all sections of this standard are intended to apply to production forgings used to make injection molds.

Remarks. Thermoplastic injection mold tooling design, construction, and validation requirements can be found in GMW15850. This specification is intended to support technical problem solving when considering the mill origin of tool steel, metallurgical certification data, and production processing only and will not specify tool build requirements.