Steel O2 · heat-treated state
Steel O2 Q&T
Properties of the Q&T condition, compared with the other O2 tempers.
Pick when the tool sees shock or thicker sections and some hardness can be traded for toughness.
What is O2 Q&T?
O2 Q&T is O2 heat treated to Q&T — pick when the tool sees shock or thicker sections and some hardness can be traded for toughness. O2 Q&T has a yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 99% of steel grades. Elongation at break is 2% and the elastic modulus is 210 GPa (30.5 Msi). O2 Q&T 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). Annealed is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- High strength — 1,750 MPa (254 ksi), better than 99% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 7/100, worse than 100% of steel grades
- Limited ductility — 2%, worse than 99% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited service temperature — 220°C (428 °F), worse than 88% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
O2 Q&T properties
Typical room-temperature values for O2 Q&T — 11 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 Q&T 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 Q&T has a yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 99% of steel grades. Elongation at break is 2% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
O2 Q&T is rated for continuous service to 220°C (428 °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 Q&T 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 Q&T 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 Q&T's machinability is not recommended (7/100, worse than 100% of steel grades); weldability poor (15/100); formability fair (40/100).
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 Q&T
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 Q&T — frequently asked
What is O2 Q&T used for?
O2 Q&T 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 Q&T?
O2 Q&T has a typical yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,000 MPa (290 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is O2 Q&T easy to machine?
Not especially — machinability is rated not recommended (7/100, worse than 100% 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 Q&T 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 Q&T?
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 Q&T 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 Q&T?
O2 Q&T is rated for continuous use to about 220°C (428 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in O2 Q&T?
Yes — O2 Q&T 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.