Steel 8615 CARB-58-62HRC
Heat-treated state
AISI/SAE 8615 · UNS G86150
CARB-58-62HRC = carburized, hardened and tempered
Production condition for gears, sprockets and cams: hard wear-resistant case with tough low-carbon core and high bending fatigue strength.
Values for the CARB-58-62HRC condition
Other 8615 tempers and conditions
8615 is listed in 8 conditions; see the grade overview at 8615.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition, best for deep machining, cold forming and gear blanking before carburizing. | 340 | 515 | 32 | 149 HB | — |
HRDefault Hot rolled | Standard mill-stock condition for carburizing bar; machine to shape then carburize and harden. | 360 | 585 | 27 | 174 HB | 7.8 % IACS |
Normalized | Uniform fine-grain structure and predictable machining response before carburizing; better core toughness than as-rolled. | 365 | 600 | 28 | 174 HB | — |
Stress relieved | Applied to cold-drawn or heavily machined blanks to reduce distortion during subsequent carburizing. | 450 | 600 | 22 | 180 HB | 7.8 % IACS |
Cold drawn | Tight tolerance, bright surface, higher yield strength for pins, shafts and screw-machine parts. | 550 | 655 | 15 | 197 HB | — |
Quenched and tempered | Used when a tough medium-strength part is wanted without a case; oil quench from ~855 °C, temper 200–540 °C. | 690 | 900 | 18 | 28 HRC | — |
core properties (25–35 HRC core) | Reference core data for design calculations of carburized 8615 parts in light/medium sections. | 690 | 930 | 16 | 30 HRC | 7.3 % IACS |
CARB-58-62HRCThis page Carburized, hardened and tempered | Production condition for gears, sprockets and cams: hard wear-resistant case with tough low-carbon core and high bending fatigue strength. | 700 | 950 | 12 | 60 HRC | — |
What is 8615 CARB-58-62HRC?
8615 CARB-58-62HRC is 8615 heat treated to CARB-58-62HRC — production condition for gears, sprockets and cams: hard wear-resistant case with tough low-carbon core and high bending fatigue strength. 8615 CARB-58-62HRC has a yield strength of 700 MPa (102 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 81% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 8615 CARB-58-62HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). HR is the default condition FabDigit quotes; CARB-58-62HRC is available on request or by drawing note.
Advantages
- High strength — 700 MPa (102 ksi), better than 81% of steel grades
Limitations
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
8615 CARB-58-62HRC properties
Typical room-temperature values for 8615 CARB-58-62HRC; 12 are specific to this condition. Other listed values are 8615 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8615 CARB-58-62HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
8615 CARB-58-62HRC has a yield strength of 700 MPa (102 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 81% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8615 CARB-58-62HRC is rated for continuous service to 180°C (356 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
8615 CARB-58-62HRC 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 8615 CARB-58-62HRC takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
8615 CARB-58-62HRC's machinability is not recommended (12/100, worse than 99% of steel grades); weldability good (60/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8615 CARB-58-62HRC
Is 8615 easy to machine?
Machines well in annealed/normalized or cold-drawn state (~65 % of 1212); finish-machine before carburizing and allow only grinding after case hardening.
Can 8615 be welded?
Weldable in the low-carbon soft condition with low-hydrogen consumables and 150–250 °C preheat; do not weld carburized surfaces and stress relieve after welding.
Can 8615 be formed, bent or molded?
Good cold formability and forgeability in the annealed condition (forge 1100–1230 °C, slow cool then normalize/anneal); carburize 900–930 °C, oil quench from 815–855 °C, temper 150–200 °C.
What surface finishes work on 8615?
No anodizing; protect with oil, phosphate, black oxide, zinc or nickel plating — bake plated parts to avoid hydrogen embrittlement; case-hardened surfaces are typically ground and shot-peened for fatigue.
8615 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 |
|---|---|---|
| CSAE 8615 / UNS G86150 | 0.13 – 0.18 | 0.16 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.4 – 0.7 | 0.55 |
| Cr | 0.4 – 0.6 | 0.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| P | ≤ 0.04 | — |
| Smax; H-grade and resulfurized variants differ | ≤ 0.04 | — |
| Fe | balance | — |
8615 CARB-58-62HRC — frequently asked
What is 8615 CARB-58-62HRC used for?
8615 CARB-58-62HRC is typically used for small gears, shafts and pins. In short: leaner, cheaper than 8620; best-machining 86xx carburizer; light-duty gear steel.
What is the yield strength of 8615 CARB-58-62HRC?
8615 CARB-58-62HRC has a typical yield strength of 700 MPa (102 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 81% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 8615 CARB-58-62HRC easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machines well in annealed/normalized or cold-drawn state (~65 % of 1212); finish-machine before carburizing and allow only grinding after case hardening.
Can 8615 CARB-58-62HRC be welded?
Yes — weldability is rated good (60/100). Weldable in the low-carbon soft condition with low-hydrogen consumables and 150–250 °C preheat; do not weld carburized surfaces and stress relieve after welding.
What surface finishes work on 8615 CARB-58-62HRC?
No anodizing; protect with oil, phosphate, black oxide, zinc or nickel plating — bake plated parts to avoid hydrogen embrittlement; case-hardened surfaces are typically ground and shot-peened for fatigue.
Can 8615 CARB-58-62HRC be formed, bent or molded?
Good cold formability and forgeability in the annealed condition (forge 1100–1230 °C, slow cool then normalize/anneal); carburize 900–930 °C, oil quench from 815–855 °C, temper 150–200 °C.
What is the maximum service temperature of 8615 CARB-58-62HRC?
8615 CARB-58-62HRC is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8615-HR and 8615-CD?
HR is the default condition — standard mill-stock condition for carburizing bar; machine to shape then carburize and harden. CD: tight tolerance, bright surface, higher yield strength for pins, shafts and screw-machine parts. Yield strength is 360 MPa in HR versus 550 MPa in CD.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASTM A322 — Steel Bars, Alloy, Standard Grades — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing practice) — ASM International (1991)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
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.