Steel A6
AISI/SAE A6 · UNS T30106
A6 (UNS T30106) is an air-hardening cold-work tool steel from the A group, alloyed with manganese, chromium and molybdenum so that it hardens through in air from an unusually low 845–870 °C with minimal size change.
Values for the Annealed condition
A6 tempers and conditions
A6 is supplied in 4 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft, machinable supply condition | Standard mill/stock condition for bar, plate and flat ground stock; machine to shape here, then harden. | 415 | 725 | 22 | 235 HB | — |
High-temper condition for maximum toughness | Temper near 400–480 °C for shear blades, heavy punches and shock tools where chipping is the failure mode. | 1,500 | 1,750 | 5 | 52 HRC | 2.7 % IACS |
air quenched 845–870 °C, tempered 175–190 °C (58–60 HRC) | Standard working condition for blanking, trimming and forming dies where maximum wear resistance is wanted. | 1,800 | 2,100 | 2 | 59 HRC | — |
air hardened from 845–870 °C, untempered (60–63 HRC) | Transient condition only — measure hardness then temper immediately; never put into service untempered. | 2,000 | 2,300 | 0.5 | 62 HRC | 2.6 % IACS |
Supply forms, finishes and certifications
Ways A6 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Precision Ground | Precision Ground Flat Stock | Surface finish |
What is A6?
A6 (UNS T30106) is an air-hardening cold-work tool steel from the A group, alloyed with manganese, chromium and molybdenum so that it hardens through in air from an unusually low 845–870 °C with minimal size change. It is bought as annealed or precision-ground flat and round stock and hardened to 50–54 HRC for blanking dies, gauges and other parts where dimensional stability through heat treatment matters more than maximum wear life. Service temperature is limited to about 200 °C and wear resistance sits below A2, the usual alternative when abrasion dominates. A6 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). A6 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 56% of steel grades. Elongation at break is 22% and the elastic modulus is 203 GPa (29.4 Msi).
What is A6 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
- Bushings and locating pins
- Cold-forming mandrels
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
- Poor heat conductor — 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
A6 properties
Typical room-temperature values for A6-Annealed; bars are the position among steel grades.
Physical3
A6 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 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 56% of steel grades. Elongation at break is 22% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal6
A6 is rated for continuous service to 200°C (392 °F). It conducts heat at 27 W/m·K (15.6 BTU/hr·ft·°F), worse than 86% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical2
A6 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 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's machinability is fair (50/100, worse than 53% of steel grades); weldability poor (20/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. A6 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A6
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.
Manufacturability
The process limits FabDigit applies to A6. Every A6 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair50 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A6 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T30106
How much does A6 cost?
A6 is a premium-cost steel ($$$), pricier than about 57% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A6 — frequently asked
What is A6 used for?
A6 is typically used for cold-work blanking and piercing dies, trim and form die inserts, gauges and master fixtures, punches and stripper plates, shear blades for thin stock and bushings and locating pins. In short: workhorse air-hardening tool.
What is the yield strength of A6?
A6 has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 56% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A6 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed condition with sharp carbide or cobalt HSS tooling and rigid setups; leave 0.1–0.3 mm grinding stock, as hardened A6 needs grinding or EDM only.
Can A6 be welded?
Not readily — weldability is rated poor (20/100). Weldable only for die repair — preheat to 250–300 °C, use matching or tool-steel filler with small stringer beads, and temper immediately after cooling to ~150 °C.
What surface finishes work on A6?
Harden in air from 845–870 °C (use a neutral atmosphere or foil wrap to prevent decarburization), temper twice, then grind, polish, or apply black oxide, nitriding or PVD for extra wear life.
Can A6 be formed, bent or molded?
Cold forming is limited to mild bending of annealed stock; hot work 900–1050 °C, then cool slowly and full anneal at ~745–790 °C with slow furnace cooling.
What is the maximum service temperature of A6?
A6 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does A6 cost?
A6 is a premium-cost steel ($$$), pricier than about 57% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in A6?
Yes — A6 is available for CNC machining; every part is priced by an engineer rather than instantly. 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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.