Overview
ASTM A681-24 covers available wrought alloy tool-steel products used to make tools, dies and fixtures. It spans several product forms and tool-steel families, but an order still needs the exact grade, form, condition, dimensions, quality controls and responsibility for final heat treatment.
Designation and acceptance
ASTM A681 is a product specification for wrought alloy tool steels, including hot- or cold-finished bar, plate, sheet, strip, rod, wire and forgings. Letter-number grade families classify service traditions, not finished-tool performance. The purchaser must connect the grade to section size, supplied hardness or annealed condition, macrostructure, decarburization, surface and the qualified hardening/tempering route.
Members and selection
| Designation | Selection context |
|---|---|
| Cold-work families (A/D/O/S) | Choose from wear, toughness, dimensional stability and section-hardening needs; family letters do not select a complete heat treatment. |
| Hot-work H family | Use for thermal-cycling tooling only after hot strength, checking resistance and cooling details are evaluated. |
| High-speed M/T families | Select from cutting temperature, carbide structure, grindability and tool-manufacturing route. |
| Special-purpose P/L/F families | Confirm intended tooling duty, product availability and supplier processing because commercial coverage varies. |
Comparison framework
| Criterion | Decision context |
|---|---|
| Grade family | Service-oriented grade families differ in alloying, hardenability, carbide population and heat-treatment response. |
| Product form | Bar, plate, sheet, strip, wire and forging routes can carry different dimensions, surface and sampling expectations. |
| Supply condition | Annealed machinable stock is not equivalent to a hardened finished tool; hardness and microstructure must be stated. |
| Quality controls | Macrostructure, decarburization, segregation, surface and ultrasonic needs can govern tool life beyond chemistry. |
Performance
- Acceptance under ASTM A681 Tool Steels depends on the exact alloy or grade, delivered condition, product geometry and specified test basis rather than the standard number alone.
- Tool life is strongly affected by carbide distribution, cleanliness, decarburization and heat-treatment execution even when chemistry conforms.
- Service suitability remains an engineering decision: hardness alone does not prove toughness, fatigue resistance, dimensional stability or suitability for the actual tool geometry.
Orderable product scope
- Hot- or cold-finished tool-steel bars and rods for machined tooling.
- Tool-steel plate, sheet and strip where the selected grade and thickness are commercially available.
- Wire or forgings within A681 scope, with form-specific dimensions and quality requirements.
Processing
- Machine in the documented soft condition with stock allowance for scale, decarburization and heat-treatment distortion.
- Qualify austenitizing, quenching, tempering and optional cryogenic treatment for the exact grade and section.
- Verify final hardness, microstructure, dimensional change and crack-free condition after tool manufacture.
Applications
- Blanking, forming and shear dies selected from cold-work families.
- Die-casting, extrusion and forging tooling selected from hot-work families.
- Cutting tools and wear fixtures when a high-speed or special-purpose family is qualified.
Selection
- Confirm that ASTM A681 Tool Steels actually covers the required product form and manufacturing route before comparing grades or quotations.
- Select alloy or grade and delivered condition from service, fabrication, section size and required property evidence; do not infer condition from a trade name.
- Require a written technical comparison and responsible-engineer approval before substituting another standard, alloy, condition or product route.
Procurement
- State ASTM A681-24, exact grade, product form and hot- or cold-finished manufacturing route.
- State dimensions, quantity, annealed/supplied hardness, surface condition, machining allowance and straightness/flatness.
- Define macrostructure, decarburization, cleanliness, ultrasonic or other special-quality requirements and sampling.
- Require heat identity, test report, marking, protective packing and agreement on final heat-treatment responsibility.