Steel 8625 CARB-CORE
Hardness band
AISI/SAE 8625 · UNS G86250
Core mechanical data used for gear-tooth bending and shaft sizing of carburized 8625 parts.
Values for the CARB-CORE condition
Other 8625 tempers and conditions
8625 is listed in 9 conditions; see the grade overview at 8625.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition; pick for heavy machining, cold forming or deep boring before carburizing. | 340 | 540 | 28 | 156 HB | — |
NDefault Normalized | Standard stocked/starting condition: uniform fine grain for machining and subsequent carburizing. | 400 | 620 | 24 | 187 HB | 7.8 % IACS |
Hot rolled | Cheapest mill condition for parts that will be fully re-heat-treated after rough machining. | 400 | 640 | 22 | 192 HB | 7.8 % IACS |
Hardenability-guaranteed (H-band) grade | Order this when Jominy end-quench hardenability limits must be certified for consistent case/core response. | 400 | 620 | 24 | 187 HB | 7.8 % IACS |
Cold drawn | Cold-finished bar with tight tolerance and better surface; use where parts are machined lightly and case-hardened locally. | 580 | 690 | 15 | 207 HB | 7.8 % IACS |
Q&T 28–32 HRC | Through-hardened medium-strength condition for shafts and non-carburized structural parts. | 800 | 965 | 17 | 30 HRC | — |
CARB-COREThis page core properties (30–40 HRC core) | Core mechanical data used for gear-tooth bending and shaft sizing of carburized 8625 parts. | 940 | 1,150 | 13 | 36 HRC | 7.8 % IACS |
Q&T 33–38 HRC | Higher-strength through-hardened condition for loaded shafts, still machinable with carbide tooling. | 1,000 | 1,150 | 14 | 35 HRC | 7.8 % IACS |
Carburized, direct quenched and low-temperature tempered (case 58–62 HRC) | Primary service condition: hard wear-resistant case over a tough 30–40 HRC core for gears and splines. | 1,000 | 1,250 | 10 | 60 HRC | — |
What is 8625 CARB-CORE?
8625 CARB-CORE is 8625 heat treated to CARB-CORE — core mechanical data used for gear-tooth bending and shaft sizing of carburized 8625 parts. 8625 CARB-CORE has a yield strength of 940 MPa (136 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 91% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). 8625 CARB-CORE 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). N is the default condition FabDigit quotes; CARB-CORE is available on request or by drawing note.
Advantages
- High strength — 940 MPa (136 ksi), better than 91% of steel grades
Limitations
- Limited formability — 8/100, worse than 97% of steel grades
- Difficult to machine — 22/100, worse than 95% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
8625 CARB-CORE properties
Typical room-temperature values for 8625 CARB-CORE; 22 are specific to this condition. Other listed values are 8625 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8625 CARB-CORE 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
8625 CARB-CORE has a yield strength of 940 MPa (136 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 91% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8625 CARB-CORE is rated for continuous service to 200°C (392 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
8625 CARB-CORE 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 8625 CARB-CORE takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability7
8625 CARB-CORE's machinability is poor (22/100, worse than 95% of steel grades); weldability poor (15/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8625 CARB-CORE
Is 8625 easy to machine?
Machine in annealed or normalized condition (≈60% of AISI 1212) with carbide tooling; finish grind after carburizing to correct heat-treat distortion.
Can 8625 be welded?
Weldable with low-hydrogen filler but requires 150–250 °C preheat and post-weld tempering; avoid welding carburized surfaces.
Can 8625 be formed, bent or molded?
Hot forge 1150–1200 °C then normalize; cold forming limited to annealed bar with generous bend radii.
What surface finishes work on 8625?
Not anodizable — protect with black oxide, manganese phosphate, zinc plating or oil; case-hardened surfaces should be ground, not chemically stripped aggressively.
8625 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 J404 / ASTM A29 | 0.23 – 0.28 | 0.25 |
| 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 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
8625 CARB-CORE — frequently asked
What is 8625 CARB-CORE used for?
8625 CARB-CORE is typically used for gears, shafts and cam parts. In short: highest core hardness 86xx; moderately loaded gear steel; H-band grade available.
What is the yield strength of 8625 CARB-CORE?
8625 CARB-CORE has a typical yield strength of 940 MPa (136 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 8625 CARB-CORE easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of steel grades). Machine in annealed or normalized condition (≈60% of AISI 1212) with carbide tooling; finish grind after carburizing to correct heat-treat distortion.
Can 8625 CARB-CORE be welded?
Not readily — weldability is rated poor (15/100). Weldable with low-hydrogen filler but requires 150–250 °C preheat and post-weld tempering; avoid welding carburized surfaces.
What surface finishes work on 8625 CARB-CORE?
Not anodizable — protect with black oxide, manganese phosphate, zinc plating or oil; case-hardened surfaces should be ground, not chemically stripped aggressively.
Can 8625 CARB-CORE be formed, bent or molded?
Hot forge 1150–1200 °C then normalize; cold forming limited to annealed bar with generous bend radii.
What is the maximum service temperature of 8625 CARB-CORE?
8625 CARB-CORE is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8625-N and 8625-CD?
N is the default condition — standard stocked/starting condition: uniform fine grain for machining and subsequent carburizing. CD: cold-finished bar with tight tolerance and better surface; use where parts are machined lightly and case-hardened locally. Yield strength is 400 MPa in N versus 580 MPa in CD.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- SAE J1268 — Hardenability Bands for Carbon and 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)
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.