Steel A7
AISI/SAE A7 · UNS T30107
A7 (T30107) is a high-carbon, high-chromium air-hardening cold-work tool steel with tungsten and vanadium additions that create a massive carbide volume for extreme abrasion resistance.
Reference datasheet — A7 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
A7 tempers and conditions
A7 is supplied in 6 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Intermediate 650–700 °C stress relief after rough machining to minimise distortion during the subsequent air hardening. | 490 | 810 | 11 | 21 HRC | 2.7 % IACS |
ANNDefault Annealed | Standard mill supply condition (bar/plate) for rough machining before air hardening. | 500 | 830 | 10 | 22 HRC | — |
Hardened & tempered 57–60 HRC | Pick when the wear part sees some shock or edge loading and a little toughness must be bought back. | 1,750 | 2,000 | 1 | 58 HRC | — |
Hardened & tempered 60–62 HRC | Balanced wear/strength setting for blanking and shear dies in abrasive stock. | 1,900 | 2,150 | 0.7 | 61 HRC | — |
Hardened + deep-cryogenic + double temper | Adds a −80 to −196 °C cryo step to convert retained austenite for maximum dimensional stability and wear life in gauges and long-run dies. | 1,950 | 2,150 | 0.5 | 65 HRC | 2.6 % IACS |
Hardened & tempered 62–65 HRC | Air-quench from ~955–980 °C and low-temper (~175–200 °C) for the highest abrasion resistance; use only where impact is essentially absent. | 2,000 | 2,250 | 0.4 | 64 HRC | — |
What is A7?
A7 (T30107) is a high-carbon, high-chromium air-hardening cold-work tool steel with tungsten and vanadium additions that create a massive carbide volume for extreme abrasion resistance. Annealed bar and plate run about 241 HB / 22 HRC (500 MPa yield, 830 MPa tensile, 10 % elongation, 203 GPa modulus) and are hardened to 57–65 HRC, with cryogenic and stress-relieved conditions on file. The trade-offs are the lowest machinability (18), weldability (12) and toughness in the A series, service limited to about 400 °C and corrosion resistance of only 20. Choose D2 or A2 where impact loading or easier processing matters. A7 has a density of 7.62 g/cm³ (0.275 lb/in³), lighter than 98% of steel grades. It melts at 1,250°C (2,282 °F). A7 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 63% of steel grades. Elongation at break is 10% and the elastic modulus is 203 GPa (29.4 Msi).
What is A7 used for?
- highly abrasive blanking dies
- wear plates
- extrusion dies for abrasive materials
- forming rolls
Limitations
- Low fracture toughness — 25 MPa·√m (22.8 ksi·√in), worse than 97% of steel grades
- Difficult to machine — 18/100, worse than 97% of steel grades
- Poor heat conductor — 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
A7 properties
Typical room-temperature values for A7-ANN; bars are the position among steel grades.
Physical3
A7 has a density of 7.62 g/cm³ (0.275 lb/in³), lighter than 98% of steel grades. It melts at 1,250°C (2,282 °F).
Mechanical17
A7 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 63% of steel grades. Elongation at break is 10% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal6
A7 is rated for continuous service to 400°C (752 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
A7 conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of A7 takes about 36 MJ of energy and emits 2.8 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 35%.
Manufacturability8
A7's machinability is poor (18/100, worse than 97% of steel grades); weldability not recommended (12/100); formability not recommended (12/100).
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. A7 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A7
Is A7 easy to machine?
Machine only in the annealed state and expect roughly a fifth of 1212 speeds — use rigid setups, sharp carbide or CBN, low feeds; hardened A7 is a grind/EDM-only material and needs CBN or SG-alumina wheels because of the vanadium carbides.
Can A7 be welded?
Avoid structural welding; for repair only, preheat 400–480 °C, use matched high-alloy tool-steel filler, keep interpass hot and temper immediately below the last tempering temperature.
Can A7 be formed, bent or molded?
Hot work at 1040–900 °C with slow furnace cooling; essentially no cold forming — annealed A7 has too little ductility and hardened A7 none at all.
A7 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 |
|---|---|---|
| Cvery high carbon to form MC/M7C3 carbides | 2 – 2.85 | 2.25 |
| Mnmax per ASTM A681 | ≥ 0.8 | 0.5 |
| Si | ≤ 0.5 | 0.35 |
| Cr | 5 – 5.75 | 5.35 |
| Vforms hard MC vanadium carbides | 3.9 – 5.15 | 4.75 |
| Mo | 0.9 – 1.4 | 1.1 |
| W | 0.5 – 1.5 | 1 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on A7?
Not anodizable; protect with oil, black oxide, phosphate or PVD (TiN/AlCrN); polishing is limited by coarse primary carbides, so aim for fine ground/lapped rather than mirror finishes.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A7 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T30107
How much does A7 cost?
A7 is a high-cost steel ($$$$), pricier than about 78% 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.
A7 — frequently asked
What is A7 used for?
A7 is typically used for highly abrasive blanking dies, wear plates, extrusion dies for abrasive materials and forming rolls. In short: most abrasion-resistant A-grade; low toughness, high carbide; grind or EDM only hardened.
What is the yield strength of A7?
A7 has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is A7 easy to machine?
Not especially — machinability is rated poor (18/100, worse than 97% of steel grades). Machine only in the annealed state and expect roughly a fifth of 1212 speeds — use rigid setups, sharp carbide or CBN, low feeds; hardened A7 is a grind/EDM-only material and needs CBN or SG-alumina wheels because of the vanadium carbides.
Can A7 be welded?
Not readily — weldability is rated not recommended (12/100). Avoid structural welding; for repair only, preheat 400–480 °C, use matched high-alloy tool-steel filler, keep interpass hot and temper immediately below the last tempering temperature.
What surface finishes work on A7?
Not anodizable; protect with oil, black oxide, phosphate or PVD (TiN/AlCrN); polishing is limited by coarse primary carbides, so aim for fine ground/lapped rather than mirror finishes.
Can A7 be formed, bent or molded?
Hot work at 1040–900 °C with slow furnace cooling; essentially no cold forming — annealed A7 has too little ductility and hardened A7 none at all.
What is the maximum service temperature of A7?
A7 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A7-ANN and A7 HT62-65?
ANN is the default condition — standard mill supply condition (bar/plate) for rough machining before air hardening. HT62-65: air-quench from ~955–980 °C and low-temper (~175–200 °C) for the highest abrasion resistance; use only where impact is essentially absent. Yield strength is 500 MPa in ANN versus 2,000 MPa in HT62-65.
How much does A7 cost?
A7 is a high-cost steel ($$$$), pricier than about 78% 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.
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)
- ASM Handbook Vol.16: Machining (Tool steel machinability ratings) — ASM International (1989)
- Tool Steels, 5th Edition (Roberts, Krauss, Kennedy) — ASM International (1998)
- UNS T30107 alloy record — SAE/ASTM Unified Numbering System (2017)
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.