Steel L1
AISI/SAE L1 · UNS T61201
L1 (UNS T61201) is an oil-hardening low-alloy tool steel from the AISI L special-purpose group, supplied spheroidize-annealed at roughly 415 MPa yield, 725 MPa tensile, 22 % elongation and 195 HB (93 HRB), then quench-tempered to 45–62 HRC for service.
Reference datasheet — L1 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
L1 tempers and conditions
L1 is supplied in 11 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stock condition for bar and flats — soft enough to machine before hardening. | 415 | 725 | 22 | 195 HB | 41 W/m·K |
Stress relieved | Intermediate treatment between rough and finish machining to minimize hardening distortion. | 430 | 740 | 20 | 200 HB | 8.5 % IACS |
Hot rolled | Mill hot-rolled black bar; normally re-annealed before machining. | 490 | 850 | 14 | 22 HRC | 8.5 % IACS |
Normalized | Grain-refining step before hardening of heavily forged or re-worked stock. | 520 | 900 | 12 | 25 HRC | 8.5 % IACS |
Cold drawn, annealed | Close-tolerance drawn or ground bar for shafts, mandrels and pins machined near-net. | 570 | 790 | 14 | 18 HRC | 8.5 % IACS |
Oil hardened + tempered ≈480–510 °C | Maximum-toughness hardened level for machine parts, collars and springs-like sections. | 1,270 | 1,450 | 10 | 45 HRC | — |
Oil hardened + tempered ≈400 °C | Use when shock loading dominates and moderate wear resistance is sufficient. | 1,480 | 1,700 | 7 | 51 HRC | — |
Oil hardened + tempered ≈260–315 °C | Tougher hardened level for shafts, cams, arbors and lightly impacted tooling. | 1,650 | 1,900 | 4 | 56 HRC | — |
Oil hardened + tempered ≈205 °C | General-purpose hardened condition balancing wear resistance and chipping risk. | 1,800 | 2,100 | 2 | 60 HRC | — |
As-quenched | Intermediate condition only — must be tempered immediately to avoid cracking. | 1,900 | 2,250 | 0.5 | 64 HRC | 7 % IACS |
Oil hardened + tempered 150–175 °C | Maximum wear resistance for gauges, taps, reamers and rolls where impact is low. | 1,950 | 2,300 | 1 | 63 HRC | 34 W/m·K |
What is L1?
L1 (UNS T61201) is an oil-hardening low-alloy tool steel from the AISI L special-purpose group, supplied spheroidize-annealed at roughly 415 MPa yield, 725 MPa tensile, 22 % elongation and 195 HB (93 HRB), then quench-tempered to 45–62 HRC for service. Engineers specify it where a hard, wear-resistant surface is needed on a core that stays tougher than high-carbon high-chromium die steels; usual forms are rounds, flats and precision-ground bar. It has essentially no corrosion resistance, poor weldability and a service ceiling near 300 °C — move to O1/CrWMn for lower quench distortion or D2/D3 for higher abrasion resistance. L1 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). L1 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 56% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
What is L1 used for?
- arbors
- cams
- collets
- rolls
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to weld — 12/100, worse than 96% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
L1 properties
Typical room-temperature values for L1-ANN; bars are the position among steel grades.
Physical3
L1 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical15
L1 has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 56% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
L1 is rated for continuous service to 300°C (572 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 62% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
L1 conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of L1 takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 30%.
Manufacturability8
L1's machinability is good (55/100, better than 62% of steel grades); weldability not recommended (12/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. L1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with L1
Is L1 easy to machine?
Machine in the spheroidize-annealed state (~65 % of AISI 1212); after hardening only grinding, EDM or CBN turning is practical.
Can L1 be welded?
Poor weldability — high carbon promotes cracking; if repair is unavoidable, preheat 300–350 °C, use matching or low-hydrogen filler and temper immediately.
Can L1 be formed, bent or molded?
Hot forge 1050→850 °C with slow cooling and a full anneal; cold forming limited to mild bending of annealed thin sections.
L1 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 |
|---|---|---|
| Chigh carbon gives 62-64 HRC after oil quench | 0.95 – 1.1 | 1 |
| Mn | 0.1 – 0.4 | 0.25 |
| Si | 0.1 – 0.4 | 0.25 |
| Crcarbide former, adds hardenability and wear resistance | 1 – 1.5 | 1.25 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on L1?
Takes a fine polish when hardened; protect with oil, black oxide, phosphating or hard chrome — the alloy has essentially no corrosion resistance.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel L1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T61201
How much does L1 cost?
L1 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
L1 — frequently asked
What is L1 used for?
L1 is typically used for arbors, cams, collets and rolls. In short: tough oil-hardening L-series steel; good annealed machinability (55); 41 W/m·K thermal conductivity.
What is the yield strength of L1?
L1 has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 725 MPa (105 ksi) — weaker than 56% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is L1 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the spheroidize-annealed state (~65 % of AISI 1212); after hardening only grinding, EDM or CBN turning is practical.
Can L1 be welded?
Not readily — weldability is rated not recommended (12/100). Poor weldability — high carbon promotes cracking; if repair is unavoidable, preheat 300–350 °C, use matching or low-hydrogen filler and temper immediately.
What surface finishes work on L1?
Takes a fine polish when hardened; protect with oil, black oxide, phosphating or hard chrome — the alloy has essentially no corrosion resistance.
Can L1 be formed, bent or molded?
Hot forge 1050→850 °C with slow cooling and a full anneal; cold forming limited to mild bending of annealed thin sections.
What is the maximum service temperature of L1?
L1 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.
What is the difference between L1-ANN and L1 QT-62?
ANN is the default condition — standard stock condition for bar and flats — soft enough to machine before hardening. QT-62: maximum wear resistance for gauges, taps, reamers and rolls where impact is low. Yield strength is 415 MPa in ANN versus 1,950 MPa in QT-62.
How much does L1 cost?
L1 is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A681 — Standard Specification for Tool Steels, Alloy — ASTM International (2015)
- 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)
- ASM Handbook Vol.16 — Machining (machinability ratings of tool steels) — ASM International (1989)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.