Steel 8115
AISI/SAE 8115 · UNS G81150
8115 is a low-carbon nickel-chromium-molybdenum carburizing steel (UNS G81150) in the SAE-AISI alloy steel series, with lean alloy content aimed at producing a hard, wear-resistant case over a tough core.
Reference datasheet — 8115 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
8115 tempers and conditions
8115 is supplied in 6 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Softest stock condition for machining of gear blanks before carburizing. | 310 | 480 | 32 | 137 HB | — |
Hot rolled | Lowest-cost mill bar form; scale and decarb layer must be machined off. | 330 | 525 | 27 | 149 HB | 7.8 % IACS |
Normalized | Uniform fine-grained structure and better machined finish before case hardening. | 370 | 560 | 28 | 163 HB | — |
Cold drawn | Tight tolerance, bright surface and higher yield for shafts and pins machined near size. | 495 | 585 | 15 | 170 HB | — |
Q&T | Direct quench and temper of small sections when moderate core strength but no case is required. | 620 | 830 | 18 | 25 HRC | — |
Carburized, quenched & tempered | Final service condition for gears and shafts: hard wear-resistant case over a tough low-carbon core. | 750 | 1,000 | 12 | 60 HRC | — |
What is 8115?
8115 is a low-carbon nickel-chromium-molybdenum carburizing steel (UNS G81150) in the SAE-AISI alloy steel series, with lean alloy content aimed at producing a hard, wear-resistant case over a tough core. Engineers use it for small case-hardened gears, pins and fasteners, and it is supplied as hot-rolled and cold-drawn bar in annealed, normalized, carburized-and-quenched-and-tempered and core-Q&T conditions; annealed material runs about 310 MPa yield, 480 MPa tensile, 32 % elongation and 137 HB (77 HRB). The low alloy content restricts hardenability to smaller sections, and mill availability is narrower than the 86xx grades, so 8615 or 8617 are the usual substitutes. 8115 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). 8115 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 83% of steel grades. Elongation at break is 32% and the elastic modulus is 205 GPa (29.7 Msi).
What is 8115 used for?
- carburized gears
- pins
- small shafts
- case-hardened fasteners
Advantages
- Ductile — tolerates forming and impact — 32%, better than 95% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Forms and bends easily — 65/100, better than 81% of steel grades
Limitations
- Low strength — 310 MPa (45 ksi), worse than 83% of steel grades
8115 properties
Typical room-temperature values for 8115-ANN; bars are the position among steel grades.
Physical3
8115 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
8115 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 83% of steel grades. Elongation at break is 32% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8115 is rated for continuous service to 350°C (662 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
8115 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 8115 takes about 26 MJ of energy and emits 1.9 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
8115's machinability is good (62/100, better than 89% of steel grades); weldability good (65/100); formability good (65/100).
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. 8115 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 8115
Is 8115 easy to machine?
Machine to near-final size in the annealed or normalized state (≈70 % of 1212); allow grinding stock for post-carburizing distortion.
Can 8115 be welded?
Readily weldable before heat treatment with low-hydrogen consumables and modest preheat; avoid welding on carburized cases.
Can 8115 be formed, bent or molded?
Good cold heading and bending in the annealed condition; hot forge 1100–1200 °C and normalize afterwards to refine grain.
8115 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 |
|---|---|---|
| Ccarburizing carbon level | 0.13 – 0.18 | 0.16 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.2 – 0.4 | 0.3 |
| Cr | 0.3 – 0.5 | 0.4 |
| Mo | 0.08 – 0.15 | 0.12 |
| P | ≤ 0.04 | |
| S | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 8115?
Not anodizable — protect with black oxide, phosphate, zinc or zinc-nickel plating (bake to avoid hydrogen embrittlement) or oil; grind and shot-peen for peak gear fatigue life.
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 8115 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G81150
How much does 8115 cost?
8115 is a budget-cost steel ($), cheaper than about 90% 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.
8115 — frequently asked
What is 8115 used for?
8115 is typically used for carburized gears, pins, small shafts and case-hardened fasteners. In short: lean-alloy carburizing grade; hard case, tough core; small-section case hardening.
What is the yield strength of 8115?
8115 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 83% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 8115 easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machine to near-final size in the annealed or normalized state (≈70 % of 1212); allow grinding stock for post-carburizing distortion.
Can 8115 be welded?
Yes — weldability is rated good (65/100). Readily weldable before heat treatment with low-hydrogen consumables and modest preheat; avoid welding on carburized cases.
What surface finishes work on 8115?
Not anodizable — protect with black oxide, phosphate, zinc or zinc-nickel plating (bake to avoid hydrogen embrittlement) or oil; grind and shot-peen for peak gear fatigue life.
Can 8115 be formed, bent or molded?
Good cold heading and bending in the annealed condition; hot forge 1100–1200 °C and normalize afterwards to refine grain.
What is the maximum service temperature of 8115?
8115 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8115-ANN and 8115 CARB-QT?
ANN is the default condition — softest stock condition for machining of gear blanks before carburizing. CARB-QT: final service condition for gears and shafts: hard wear-resistant case over a tough low-carbon core. Yield strength is 310 MPa in ANN versus 750 MPa in CARB-QT.
How much does 8115 cost?
8115 is a budget-cost steel ($), cheaper than about 90% 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
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Alloy H Steels — SAE International (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (Carburizing) — ASM International (1991)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
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.