A6

Data under review

A6 is a low-temperature air-hardening cold work steel: its high manganese content lets it harden from temperatures normally used for oil-hardening grades. The result is very low distortion with moderate wear resistance.

Hardness54–59 HRC

AISIA6

CategoryTool Steel

Chemical composition

Element	Content (%)
C	0.65–0.75
Si	0.10–0.50
Mn	1.80–2.50
Cr	0.90–1.20
Mo	0.90–1.40

Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.

Properties

Delivery condition	Annealed
Hardness (hardened)	54–59 HRC
Density	7.85 g/cm³

Heat treatment

Harden at an unusually low 830–870 °C in air; temper 150–260 °C.

Equivalent grades

Standard	Designation
aisi	A6

Compare side by side: A6 vs A4 · A6 vs A2

Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.

Applications & Processing

Applications: Dies and punches needing minimal size change, gauges, forming tools, intricate short-run tooling.

Processing: The low austenitizing temperature reduces scaling and decarburization risk; toughness is good for a cold work grade.

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Source: ASTM A681 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.