Steel 8625
AISI/SAE 8625 · UNS G86250
8625 is a nickel-chromium-molybdenum case-hardening steel (AISI/SAE 8625, UNS G86250) that delivers higher core hardness than 8620 after carburizing.
Reference datasheet — 8625 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 N condition
8625 tempers and conditions
8625 is supplied in 9 conditions, soft to hard. N is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
8625 is a nickel-chromium-molybdenum case-hardening steel (AISI/SAE 8625, UNS G86250) that delivers higher core hardness than 8620 after carburizing. It suits moderately loaded gears, shafts and cam parts and is supplied hot-rolled, annealed, normalized, cold-drawn, direct-quenched or core-treated after carburizing, or quenched-and-tempered to 28–32 or 33–38 HRC, with an 8625H hardenability variant. Default-condition values are 400 MPa yield, 620 MPa tensile, 24 % elongation and 187 HB (91 HRB). Cold forming is limited to annealed bar with generous radii and the steel has no corrosion resistance; 8622 is the nearest alternative when higher ductility is wanted. 8625 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). 8625 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
What is 8625 used for?
- gears
- shafts
- cam parts
8625 properties
Typical room-temperature values for 8625-N; bars are the position among steel grades.
Physical3
8625 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 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8625 is rated for continuous service to 400°C (752 °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
8625 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 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's machinability is good (60/100, better than 83% of steel grades); weldability good (55/100); formability good (55/100).
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. 8625 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 8625
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.
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 |
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.
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 8625 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G86250
How much does 8625 cost?
8625 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.
8625 — frequently asked
What is 8625 used for?
8625 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?
8625 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 8625 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% 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 be welded?
Yes — weldability is rated good (55/100). 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?
Not anodizable — protect with black oxide, manganese phosphate, zinc plating or oil; case-hardened surfaces should be ground, not chemically stripped aggressively.
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 is the maximum service temperature of 8625?
8625 is rated for continuous use to about 400°C (752 °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.
How much does 8625 cost?
8625 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)
- 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; 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.