Steel O2 · temper · default condition
Steel O2 Annealed
Properties of the Annealed condition, compared with the other O2 tempers.
Standard stock condition for machining, drilling and grinding before hardening.
What is O2 Annealed?
O2 Annealed is O2 in the Annealed temper — standard stock condition for machining, drilling and grinding before hardening. O2 Annealed 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 25% and the elastic modulus is 210 GPa (30.5 Msi). O2 Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 76% of steel grades
Limitations
- Difficult to weld — 15/100, worse than 91% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 77% of steel grades
O2 Annealed properties
Typical room-temperature values for O2 Annealed — 12 properties are specific to this condition; the rest are grade-level values shared by every O2 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
O2 Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
O2 Annealed 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 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
O2 Annealed is rated for continuous service to 300°C (572 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
O2 Annealed conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of O2 Annealed takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 35%.
Manufacturability6
O2 Annealed's machinability is fair (48/100, worse than 57% of steel grades); weldability poor (15/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other O2 tempers and conditions
O2 is also supplied in 5 other conditions. The full side-by-side table is on the O2 overview.
- AnnealedDefaultStandard stock condition for machining, drilling and grinding before hardening.420 MPa yield · 205 HB
- Hardened & TemperedStandard working condition for blanking dies, gauges and knife/cutting edges needing maximum wear resistance.1,900 MPa yield · 61 HRC
- Q&TPick when the tool sees shock or thicker sections and some hardness can be traded for toughness.1,750 MPa yield · 58 HRC
- H&T 54-56 HRCHighest-toughness tempered condition for shear blades and impact-loaded punches.1,600 MPa yield · 55 HRC
Working with O2 Annealed
Is O2 easy to machine?
Machine only in the annealed state with sharp HSS or coated carbide, moderate speeds and rigid setups; after hardening only grinding or EDM is practical.
Can O2 be welded?
Not recommended for structural joints; repair-weld with matching tool-steel filler at 300–400 °C preheat and temper immediately afterwards.
Can O2 be formed, bent or molded?
Hot work at 900–1050 °C with slow cooling; cold forming is limited — harden from 790–815 °C, oil quench (small sections may be air-cooled) and temper at 150–200 °C for 60–62 HRC, expecting only ~0.02 % size change.
What surface finishes work on O2?
Takes a fine polish for die faces; protect with oil, black oxide, phosphate or thin nitride/PVD coatings since the alloy has essentially no corrosion resistance.
O2 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 | 0.85 – 0.95 | 0.9 |
| MnDIN 1.2842 / 90MnCrV8 uses Mn 1.80–2.20 | 1.4 – 1.8 | 1.6 |
| Si | 0.1 – 0.5 | 0.25 |
| Cr1.2842: 0.20–0.50 | 0 – 0.5 | 0.3 |
| V1.2842: 0.05–0.20 | 0 – 0.3 | 0.1 |
| Mo | 0 – 0.3 | — |
| W | 0 – 0.3 | — |
| Ni | 0 – 0.3 | — |
| P | 0 – 0.03 | — |
| S | 0 – 0.03 | — |
| Fe | balance | — |
O2 Annealed — frequently asked
What is O2 Annealed used for?
O2 Annealed is typically used for blanking and piercing dies, punches, shear and trim blades, gauges and templates, thread-rolling and knurling tools and woodworking knives. In short: oil-hardening tool steel.
What is the yield strength of O2 Annealed?
O2 Annealed 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 O2 Annealed easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Machine only in the annealed state with sharp HSS or coated carbide, moderate speeds and rigid setups; after hardening only grinding or EDM is practical.
Can O2 Annealed be welded?
Not readily — weldability is rated poor (15/100). Not recommended for structural joints; repair-weld with matching tool-steel filler at 300–400 °C preheat and temper immediately afterwards.
What surface finishes work on O2 Annealed?
Takes a fine polish for die faces; protect with oil, black oxide, phosphate or thin nitride/PVD coatings since the alloy has essentially no corrosion resistance.
Can O2 Annealed be formed, bent or molded?
Hot work at 900–1050 °C with slow cooling; cold forming is limited — harden from 790–815 °C, oil quench (small sections may be air-cooled) and temper at 150–200 °C for 60–62 HRC, expecting only ~0.02 % size change.
What is the maximum service temperature of O2 Annealed?
O2 Annealed is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in O2 Annealed?
Yes — O2 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 — Alloy Tool Steels — ASTM International (2015)
- EN ISO 4957 — Tool steels (90MnCrV8 / 1.2842) — CEN/ISO (2018)
- GB/T 1299 (9Mn2V) — SAC (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- 1.2842 / 90MnCrV8 cold-work tool steel datasheet — European tool-steel producers (2022)
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.