Steel A8 · temper · default condition
Steel A8 Annealed
Properties of the Annealed condition, compared with the other A8 tempers.
Standard stock condition for machining dies and inserts before hardening.
What is A8 Annealed?
A8 Annealed is A8 in the Annealed temper — standard stock condition for machining dies and inserts before hardening. A8 Annealed has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 63% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi). A8 Annealed has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
- Poor heat conductor — 24.5 W/m·K (14.2 BTU/hr·ft·°F), worse than 89% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 86% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
A8 Annealed properties
Typical room-temperature values for A8 Annealed — 11 properties are specific to this condition; the rest are grade-level values shared by every A8 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
A8 Annealed has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
A8 Annealed has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 63% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A8 Annealed is rated for continuous service to 200°C (392 °F). It conducts heat at 24.5 W/m·K (14.2 BTU/hr·ft·°F), worse than 89% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
A8 Annealed conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of A8 Annealed takes about 34 MJ of energy and emits 2.6 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 40%.
Manufacturability7
A8 Annealed's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (20/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other A8 tempers and conditions
A8 is also supplied in 6 other conditions. The full side-by-side table is on the A8 overview.
- AnnealedDefaultStandard stock condition for machining dies and inserts before hardening.500 MPa yield · 220 HB
- Hardened & TemperedUse when the tool is delivered hardened but the exact hardness band is set by the toolmaker.1,950 MPa tensile
- H&T 60-62 HRCChoose for thin-stock blanking punches and wear inserts where abrasion, not impact, dominates.1,850 MPa yield · 61 HRC
- Q&TGeneral working condition: good balance of toughness and wear for blanking and forming tools.1,700 MPa yield · 59 HRC
- H&T 58-60 HRCThe usual compromise between wear resistance and toughness for blanking and forming dies.1,700 MPa yield · 59 HRC
- H&T 56-58 HRCPick for heavy shear blades, thick-section punches and impact-loaded dies where chipping is the failure mode.1,600 MPa yield · 57 HRC
Working with A8 Annealed
Is A8 easy to machine?
Machine only in the annealed state (~220 HB) with rigid setups and coated carbide; after hardening use grinding or EDM plus a stress-relief temper.
Can A8 be welded?
Weld only for repair — preheat 300–370 °C, use matched 5 % Cr tool-steel filler, keep interpass temperature and temper immediately below the last tempering temperature.
Can A8 be formed, bent or molded?
Hot work at 1050–900 °C followed by slow cooling; no meaningful cold forming — air harden from 980–1010 °C with minimal size change and double temper at 200–540 °C.
What surface finishes work on A8?
Takes a good ground/lapped finish; protect with oil, black oxide, nitriding or PVD TiN/CrN coatings since the 5 % Cr gives no stainless behaviour.
A8 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 | 0.5 – 0.6 | 0.55 |
| Mn | 0.2 – 0.5 | 0.35 |
| Si | 0.75 – 1.1 | 0.95 |
| Cr | 4.75 – 5.5 | 5.1 |
| Mo | 1.15 – 1.65 | 1.3 |
| W | 1 – 1.5 | 1.25 |
| Voptional/residual per ASTM A681 | ≤ 0.25 | 0.2 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
A8 Annealed — frequently asked
What is A8 Annealed used for?
A8 Annealed is typically used for cold-work blanking and forming dies, slitter knives, shear blades, punches and die inserts, trim and pierce tooling and cold-forming die inserts for shock loading. In short: air-hardening tool steel.
What is the yield strength of A8 Annealed?
A8 Annealed has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is A8 Annealed easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine only in the annealed state (~220 HB) with rigid setups and coated carbide; after hardening use grinding or EDM plus a stress-relief temper.
Can A8 Annealed be welded?
Not readily — weldability is rated poor (20/100). Weld only for repair — preheat 300–370 °C, use matched 5 % Cr tool-steel filler, keep interpass temperature and temper immediately below the last tempering temperature.
What surface finishes work on A8 Annealed?
Takes a good ground/lapped finish; protect with oil, black oxide, nitriding or PVD TiN/CrN coatings since the 5 % Cr gives no stainless behaviour.
Can A8 Annealed be formed, bent or molded?
Hot work at 1050–900 °C followed by slow cooling; no meaningful cold forming — air harden from 980–1010 °C with minimal size change and double temper at 200–540 °C.
What is the maximum service temperature of A8 Annealed?
A8 Annealed 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.
Can FabDigit make parts in A8 Annealed?
Yes — A8 Annealed 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)
- A8 air-hardening cold-work tool steel datasheet — Tool-steel producers (Crucible/Latrobe/Böhler-type data) (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.