Steel A7 HT-CRYO
Heat-treated state
AISI/SAE A7 · UNS T30107
HT-CRYO = 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.
Values for the HT-CRYO condition
Other A7 tempers and conditions
A7 is listed in 6 conditions; see the grade overview at A7.
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 | — |
HT-CRYOThis page 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 HT-CRYO?
A7 HT-CRYO is A7 heat treated to HT-CRYO — 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. A7 HT-CRYO has a yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,150 MPa (312 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 207 GPa (30 Msi). A7 HT-CRYO 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). ANN is the default condition FabDigit quotes; HT-CRYO is available on request or by drawing note.
Advantages
- High strength — 1,950 MPa (283 ksi), better than 100% of steel grades
- Good corrosion resistance — 25/100, better than 92% of steel grades
Limitations
- Limited ductility — 0.5%, worse than 100% of steel grades
- Low fracture toughness — 10 MPa·√m (9.1 ksi·√in), worse than 100% of steel grades
- Difficult to machine — 2/100, worse than 100% of steel grades
- Difficult to weld — 3/100, worse than 100% of steel grades
- Limited formability — 1/100, worse than 100% of steel grades
A7 HT-CRYO properties
Typical room-temperature values for A7 HT-CRYO; 21 are specific to this condition. Other listed values are A7 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A7 HT-CRYO 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 HT-CRYO has a yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,150 MPa (312 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A7 HT-CRYO is rated for continuous service to 200°C (392 °F). It conducts heat at 19 W/m·K (11 BTU/hr·ft·°F), worse than 97% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
A7 HT-CRYO conducts electricity at 2.6 % IACS, worse than 97% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 92% of steel grades.
Sustainability4
Producing a kilogram of A7 HT-CRYO 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 HT-CRYO's machinability is not recommended (2/100, worse than 100% of steel grades); weldability not recommended (3/100); formability not recommended (1/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A7 HT-CRYO
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.
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.
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 | — |
A7 HT-CRYO — frequently asked
What is A7 HT-CRYO used for?
A7 HT-CRYO 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 HT-CRYO?
A7 HT-CRYO has a typical yield strength of 1,950 MPa (283 ksi) and a tensile strength of 2,150 MPa (312 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is A7 HT-CRYO easy to machine?
Not especially — machinability is rated not recommended (2/100, worse than 100% 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 HT-CRYO be welded?
Not readily — weldability is rated not recommended (3/100). 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 HT-CRYO?
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 HT-CRYO 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 HT-CRYO?
A7 HT-CRYO 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.
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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.