Steel A3 Stress Relieved
Heat-treated state
AISI/SAE A3 · UNS T30103
Intermediate step on large or asymmetric tools to minimise distortion during air hardening.
Values for the Stress Relieved condition
Other A3 tempers and conditions
A3 is listed in 6 conditions; see the grade overview at A3.
- Stress Relieved
- Annealed
- Q&T 56-58 HRC
- Nitrided
- Q&T 58-60 HRC
- Q&T 60-62 HRC
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress RelievedThis page Stress relieved after rough machining (~650–700 °C, annealed base) | Intermediate step on large or asymmetric tools to minimise distortion during air hardening. | 420 | 740 | 21 | 18 HRC | 2.7 % IACS |
AnnealedDefault soft, as-supplied bar / plate / precision ground flat stock | Standard stock condition for machining the tool before hardening. | 430 | 760 | 20 | 19 HRC | — |
Hardened and tempered to 56–58 HRC | Pick when impact and chipping resistance matter more than maximum wear life. | 1,700 | 1,950 | 3 | 57 HRC | — |
Hardened, tempered and gas/plasma nitrided surface | Use when galling or adhesive wear dominates; core stays at 58–60 HRC with ~1100 HV case. | 1,750 | 2,000 | 1.5 | 59 HRC | 2.7 % IACS |
Hardened and tempered to 58–60 HRC | General-purpose working hardness for blanking and forming dies — balanced wear and toughness. | 1,850 | 2,100 | 2 | 59 HRC | — |
Hardened and tempered to 60–62 HRC | Highest practical wear resistance for A3 — for abrasive blanking, trim edges and gauges with rigid support. | 2,000 | 2,250 | 1 | 61 HRC | — |
What is A3 Stress Relieved?
A3 Stress Relieved is A3 heat treated to Stress Relieved — intermediate step on large or asymmetric tools to minimise distortion during air hardening. A3 Stress Relieved has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 740 MPa (107 ksi) — weaker than 53% of steel grades. Elongation at break is 21% and the elastic modulus is 203 GPa (29.4 Msi). A3 Stress Relieved has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 90% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Stress Relieved is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Poor heat conductor — 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades
- Difficult to weld — 18/100, worse than 87% of steel grades
- High embodied carbon — 2.6 kg CO₂/kg, worse than 87% of steel grades
A3 Stress Relieved properties
Typical room-temperature values for A3 Stress Relieved; 23 are specific to this condition. Other listed values are A3 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A3 Stress Relieved has a density of 7.86 g/cm³ (0.284 lb/in³), heavier than 90% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
A3 Stress Relieved has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 740 MPa (107 ksi) — weaker than 53% of steel grades. Elongation at break is 21% and the elastic modulus is 203 GPa (29.4 Msi).
Thermal6
A3 Stress Relieved is rated for continuous service to 200°C (392 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades. Thermal expansion is 10.7 µm/m·K (5.94 µin/in·°F).
Electrical3
A3 Stress Relieved conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A3 Stress Relieved takes about 36 MJ of energy and emits 2.6 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 30%.
Manufacturability8
A3 Stress Relieved's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (18/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A3 Stress Relieved
Is A3 easy to machine?
Machine in the annealed condition with rigid setups, sharp carbide or cobalt HSS tooling and moderate speeds; the high vanadium carbide content accelerates tool and wheel wear, so allow generous grinding stock and finish by grinding after hardening.
Can A3 be welded?
Poor weldability — repair welding only, with 300–450 °C preheat, matching or Cr-Mo tool-steel filler, minimal heat input and an immediate temper at the previous tempering temperature.
Can A3 be formed, bent or molded?
Cold forming is impractical; hot work at 900–1050 °C with slow controlled cooling and full anneal (~845–870 °C, slow cool) afterwards; austenitize 940–970 °C, air quench, temper 175–540 °C — dimensional change on hardening is very small.
What surface finishes work on A3?
Not corrosion resistant: protect with oil, black oxide, phosphating, nitriding or PVD TiN/CrN; polishing is possible but coarse vanadium carbides limit true mirror finish.
A3 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 |
|---|---|---|
| CASTM A681 grade A3 | 1.2 – 1.3 | 1.25 |
| Mn | 0.4 – 0.6 | 0.5 |
| Si | ≤ 0.5 | 0.3 |
| Cr | 4.75 – 5.5 | 5.1 |
| Mo | 0.9 – 1.4 | 1.1 |
| Vhigh V gives extra wear resistance vs A2 | 0.8 – 1.4 | 1 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
A3 Stress Relieved — frequently asked
What is A3 Stress Relieved used for?
A3 Stress Relieved is typically used for blanking and piercing dies, forming and coining punches, trim dies and die inserts, shear and slitter blades, thread-rolling dies and cold-forming tooling. In short: air-hardening cold-work tool.
What is the yield strength of A3 Stress Relieved?
A3 Stress Relieved has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 740 MPa (107 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is A3 Stress Relieved easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the annealed condition with rigid setups, sharp carbide or cobalt HSS tooling and moderate speeds; the high vanadium carbide content accelerates tool and wheel wear, so allow generous grinding stock and finish by grinding after hardening.
Can A3 Stress Relieved be welded?
Not readily — weldability is rated poor (18/100). Poor weldability — repair welding only, with 300–450 °C preheat, matching or Cr-Mo tool-steel filler, minimal heat input and an immediate temper at the previous tempering temperature.
What surface finishes work on A3 Stress Relieved?
Not corrosion resistant: protect with oil, black oxide, phosphating, nitriding or PVD TiN/CrN; polishing is possible but coarse vanadium carbides limit true mirror finish.
Can A3 Stress Relieved be formed, bent or molded?
Cold forming is impractical; hot work at 900–1050 °C with slow controlled cooling and full anneal (~845–870 °C, slow cool) afterwards; austenitize 940–970 °C, air quench, temper 175–540 °C — dimensional change on hardening is very small.
What is the maximum service temperature of A3 Stress Relieved?
A3 Stress Relieved 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 A3 Stress Relieved?
Yes — A3 Stress Relieved 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)
- SAE J437/J438 — Tool and Die Steels — SAE International (2015)
- ASM Handbook Vol.1: Properties and Selection: Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- ASM Specialty Handbook: Tool Materials — ASM International (1995)
- ASM Handbook Vol.16: Machining — ASM International (1989)
- Air-hardening cold work tool steel (A2/A3 class) datasheets — Böhler / Crucible Industries (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.