Steel A6 · heat-treated state
Steel A6 Hardened & Tempered
Properties of the Hardened & Tempered condition, compared with the other A6 tempers.
Standard working condition for blanking, trimming and forming dies where maximum wear resistance is wanted.
What is A6 Hardened & Tempered?
A6 Hardened & Tempered is A6 heat treated to Hardened & Tempered — standard working condition for blanking, trimming and forming dies where maximum wear resistance is wanted. A6 Hardened & Tempered has a yield strength of 1,800 MPa (261 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 99% of steel grades. Elongation at break is 2% and the elastic modulus is 203 GPa (29.4 Msi). A6 Hardened & Tempered has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,425°C (2,597 °F). Annealed is the default condition FabDigit quotes; Hardened & Tempered is available on request or by drawing note.
Advantages
- High strength — 1,800 MPa (261 ksi), better than 99% of steel grades
Limitations
- Difficult to machine — 8/100, worse than 100% of steel grades
- Limited ductility — 2%, worse than 99% of steel grades
- Limited service temperature — 175°C (347 °F), worse than 99% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 86% of steel grades
- Poor heat conductor — 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 85% of steel grades
A6 Hardened & Tempered properties
Typical room-temperature values for A6 Hardened & Tempered — 12 properties are specific to this condition; the rest are grade-level values shared by every A6 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
A6 Hardened & Tempered has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
A6 Hardened & Tempered has a yield strength of 1,800 MPa (261 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 99% of steel grades. Elongation at break is 2% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal6
A6 Hardened & Tempered is rated for continuous service to 175°C (347 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 85% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical2
A6 Hardened & Tempered has an electrical resistivity of 6×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of A6 Hardened & Tempered takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 45%.
Manufacturability8
A6 Hardened & Tempered's machinability is not recommended (8/100, worse than 100% of steel grades); weldability poor (20/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other A6 tempers and conditions
A6 is also supplied in 5 other conditions. The full side-by-side table is on the A6 overview.
- AnnealedDefaultStandard mill/stock condition for bar, plate and flat ground stock; machine to shape here, then harden.415 MPa yield · 235 HB
- Hardened & TemperedStandard working condition for blanking, trimming and forming dies where maximum wear resistance is wanted.1,800 MPa yield · 59 HRC
- Q&THigher tempering temperature (~230–330 °C) trades a few points of hardness for better toughness in shock-loaded dies and punches.1,650 MPa yield · 56 HRC
- H&T 50-54 HRCTemper near 400–480 °C for shear blades, heavy punches and shock tools where chipping is the failure mode.1,500 MPa yield · 52 HRC
Working with A6 Hardened & Tempered
Is A6 easy to machine?
Machine in the annealed condition with sharp carbide or cobalt HSS tooling and rigid setups; leave 0.1–0.3 mm grinding stock, as hardened A6 needs grinding or EDM only.
Can A6 be welded?
Weldable only for die repair — preheat to 250–300 °C, use matching or tool-steel filler with small stringer beads, and temper immediately after cooling to ~150 °C.
Can A6 be formed, bent or molded?
Cold forming is limited to mild bending of annealed stock; hot work 900–1050 °C, then cool slowly and full anneal at ~745–790 °C with slow furnace cooling.
What surface finishes work on A6?
Harden in air from 845–870 °C (use a neutral atmosphere or foil wrap to prevent decarburization), temper twice, then grind, polish, or apply black oxide, nitriding or PVD for extra wear life.
A6 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.65 – 0.75 | 0.7 |
| Mnhigh Mn gives deep air hardening from low austenitizing temperature | 1.8 – 2.5 | 2.1 |
| Si | ≤ 0.5 | 0.3 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.9 – 1.4 | 1.15 |
| Niresidual | ≤ 0.3 | — |
| Voptional grain refiner | ≤ 0.3 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
A6 Hardened & Tempered — frequently asked
What is A6 Hardened & Tempered used for?
A6 Hardened & Tempered is typically used for cold-work blanking and piercing dies, trim and form die inserts, gauges and master fixtures, punches and stripper plates, shear blades for thin stock and bushings and locating pins. In short: workhorse air-hardening tool.
What is the yield strength of A6 Hardened & Tempered?
A6 Hardened & Tempered has a typical yield strength of 1,800 MPa (261 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is A6 Hardened & Tempered easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of steel grades). Machine in the annealed condition with sharp carbide or cobalt HSS tooling and rigid setups; leave 0.1–0.3 mm grinding stock, as hardened A6 needs grinding or EDM only.
Can A6 Hardened & Tempered be welded?
Not readily — weldability is rated poor (20/100). Weldable only for die repair — preheat to 250–300 °C, use matching or tool-steel filler with small stringer beads, and temper immediately after cooling to ~150 °C.
What surface finishes work on A6 Hardened & Tempered?
Harden in air from 845–870 °C (use a neutral atmosphere or foil wrap to prevent decarburization), temper twice, then grind, polish, or apply black oxide, nitriding or PVD for extra wear life.
Can A6 Hardened & Tempered be formed, bent or molded?
Cold forming is limited to mild bending of annealed stock; hot work 900–1050 °C, then cool slowly and full anneal at ~745–790 °C with slow furnace cooling.
What is the maximum service temperature of A6 Hardened & Tempered?
A6 Hardened & Tempered is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in A6 Hardened & Tempered?
Yes — A6 Hardened & Tempered is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A681 — Standard Specification for Tool Steels Alloy — ASTM International (2022)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- A6 air-hardening tool steel datasheet — Crucible / Latrobe / Hudson Tool Steel (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.