Steel L2 OQT-650
Heat-treated state
AISI/SAE L2 · UNS T61202
OQT-650 = oil quenched + tempered 650 °C
Pre-hardened machinable condition for structural machine components that will not be re-heat-treated.
Values for the OQT-650 condition
Other L2 tempers and conditions
L2 is listed in 9 conditions; see the grade overview at L2.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition for machining tools and parts before hardening. | 510 | 710 | 25 | 183 HB | — |
Hot rolled | Mill-finish rolled bar taken for re-forging or as-purchased blanks that will be annealed then hardened. | 560 | 850 | 18 | 22 HRC | 7.8 % IACS |
Cold Drawn, annealed base | Choose for close-tolerance shafting and tool blanks needing minimal cleanup before hardening. | 620 | 790 | 16 | 17 HRC | 7.8 % IACS |
OQT-650This page Oil quenched + tempered 650 °C | Pre-hardened machinable condition for structural machine components that will not be re-heat-treated. | 760 | 930 | 20 | 31 HRC | — |
Oil quenched + tempered 540 °C | High-toughness machine-part condition for shafts, gears and springs made from the lower-carbon L2 variant. | 1,105 | 1,240 | 14 | 40 HRC | — |
Oil quenched + tempered 425 °C | Tough working hardness for chisels, spindles, arbors and impact-loaded tooling. | 1,380 | 1,550 | 10 | 46 HRC | — |
Oil quenched + tempered 315 °C | Balanced hardness/toughness for shear blades, forming dies and heavily loaded punches. | 1,550 | 1,790 | 8 | 52 HRC | — |
Oil quenched + tempered 205 °C | Maximum hardness condition for punches, blanking dies, taps and knurls where wear resistance dominates. | 1,790 | 2,070 | 5 | 56 HRC | — |
Hardened | L2 austenitized ~845–870 °C and oil quenched to full martensitic hardness with only a minimal stress-relief temper, giving maximum hardness and wear resistance but low toughness; used for chisels, punches, knurls and shear blades that are ground to size. | 1,800 | 2,150 | 2 | 61 HRC | 33 W/m·K |
What is L2 OQT-650?
L2 OQT-650 is L2 heat treated to OQT-650 — pre-hardened machinable condition for structural machine components that will not be re-heat-treated. L2 OQT-650 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 85% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi). L2 OQT-650 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). ANN is the default condition FabDigit quotes; OQT-650 is available on request or by drawing note.
Advantages
- High service temperature — 480°C (896 °F), better than 88% of steel grades
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
Limitations
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
L2 OQT-650 properties
Typical room-temperature values for L2 OQT-650; 12 are specific to this condition. Other listed values are L2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
L2 OQT-650 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
L2 OQT-650 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 85% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
L2 OQT-650 is rated for continuous service to 480°C (896 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
L2 OQT-650 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of L2 OQT-650 takes about 31 MJ of energy and emits 2.3 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 35%.
Manufacturability8
L2 OQT-650's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (25/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with L2 OQT-650
Is L2 easy to machine?
Machine in the annealed condition (~65 % of AISI 1212) with sharp carbide or M2 HSS tooling; above 45 HRC switch to grinding, EDM or CBN.
Can L2 be welded?
Not intended for welding — if repair is unavoidable, preheat 300–400 °C, use a matching or low-hydrogen Cr-V filler and re-temper immediately.
Can L2 be formed, bent or molded?
Hot work at 900–1080 °C with slow cooling and a full spheroidize anneal (760–790 °C, slow cool) afterwards; cold forming is limited to mild bending of annealed stock.
What surface finishes work on L2?
Fine grain permits a good ground and polished finish; protect the bare surface by oiling, black oxide, phosphating, nitriding or hard chrome — no anodizing.
L2 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 |
|---|---|---|
| Ccarbon level selected by application: ~0.50 % for tough machine parts, ~1.00 % for wear tooling | 0.45 – 1 | 0.7 |
| Mn | 0.1 – 0.9 | 0.5 |
| Si | ≤ 0.5 | 0.25 |
| Cr | 0.7 – 1.2 | 1 |
| Vgrain refiner | 0.1 – 0.3 | 0.2 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
L2 OQT-650 — frequently asked
What is L2 OQT-650 used for?
L2 OQT-650 is typically used for arbors and collets, cutting tools, machine tool parts, gauges and wear-resistant pins and rolls. In short: tough oil-hardening Cr-V steel; wide tempering range; fine grain, good polish.
What is the yield strength of L2 OQT-650?
L2 OQT-650 has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is L2 OQT-650 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed condition (~65 % of AISI 1212) with sharp carbide or M2 HSS tooling; above 45 HRC switch to grinding, EDM or CBN.
Can L2 OQT-650 be welded?
Not readily — weldability is rated poor (25/100). Not intended for welding — if repair is unavoidable, preheat 300–400 °C, use a matching or low-hydrogen Cr-V filler and re-temper immediately.
What surface finishes work on L2 OQT-650?
Fine grain permits a good ground and polished finish; protect the bare surface by oiling, black oxide, phosphating, nitriding or hard chrome — no anodizing.
Can L2 OQT-650 be formed, bent or molded?
Hot work at 900–1080 °C with slow cooling and a full spheroidize anneal (760–790 °C, slow cool) afterwards; cold forming is limited to mild bending of annealed stock.
What is the maximum service temperature of L2 OQT-650?
L2 OQT-650 is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between L2-ANN and L2 Hard?
ANN is the default condition — standard stocked condition for machining tools and parts before hardening. Hard: l2 austenitized ~845–870 °C and oil quenched to full martensitic hardness with only a minimal stress-relief temper, giving maximum hardness and wear resistance but low toughness; used for chisels, punches, knurls and shear blades that are ground to size. Yield strength is 510 MPa in ANN versus 1,800 MPa in Hard.
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 — ASM International (1990)
- Tool Steels, 5th Edition (Roberts, Krauss, Kennedy) — ASM International (1998)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
- UNS T61202 alloy record — SAE/ASTM Unified Numbering System (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.