Hardness Conversion

Material-Specific

Choose the material family to display its complete validated hardness conversion table. Values are approximate equivalents, not substitute test results.

Material

Hardness Conversion Chart

Validated table values only.

Reference & Use

Engineering basis: ASTM E140 material-specific hardness relationships, independently cross-checked against NIST guidance and published engineering conversion references. Machinist Companion stores normalized conversion points and interpolates only inside supported ranges.

ASTM and NIST emphasize that conversions are approximate and material-dependent. Alloy, grain structure, processing and heat treatment can change the relationship. Use a direct hardness test whenever the governing specification requires one.

Current controlled material families: non-austenitic carbon/alloy/tool steel; nickel/high-nickel alloys; wrought aluminum; alloyed white iron; annealed austenitic stainless plate; and Copper Nos. 102–142 (controlled subset).

Engineering reference only. Verify critical dimensions, parameters, machine/tool limits and governing specifications before use. Terms & Disclaimer