Steel 8622 CARB
Heat-treated state
AISI/SAE 8622 · UNS G86220
CARB = carburized, quenched & tempered
The intended service condition: hard wear/pitting-resistant case over a tough 30–40 HRC core for gears and pinions.
Values for the CARB condition
Other 8622 tempers and conditions
8622 is listed in 8 conditions; see the grade overview at 8622.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked condition for machining gear blanks before carburizing; softest and most stable. | 390 | 550 | 30 | 163 HB | — |
Hardenability-guaranteed (H-band) bar | Order H-grade when Jominy end-quench hardenability must be inside the SAE J1268 band for consistent gear distortion and core hardness. | 395 | 560 | 29 | 170 HB | 7.8 % IACS |
Hot rolled | Cheapest mill condition for parts that will be fully re-heat-treated (carburized) after rough machining. | 400 | 630 | 23 | 183 HB | — |
Normalized | Use to refine grain and homogenize forgings before carburizing; better toughness uniformity than as-rolled. | 400 | 660 | 26 | 11 HRC | 7.8 % IACS |
Cold drawn | Pick for close-tolerance, bright-finish bar going straight to light machining or as-carburized small shafts. | 600 | 700 | 15 | 207 HB | — |
oil quenched and tempered (through-hardened core) | Direct-hardened condition for shafts and fasteners needing uniform mid-strength without a case. | 800 | 950 | 17 | 30 HRC | — |
oil quenched, lower tempering temperature | Higher-strength through-hardened option for small sections where toughness can be traded for load capacity. | 930 | 1,080 | 15 | 34 HRC | — |
CARBThis page Carburized, quenched & tempered | The intended service condition: hard wear/pitting-resistant case over a tough 30–40 HRC core for gears and pinions. | 950 | 1,250 | 11 | 60 HRC | — |
What is 8622 CARB?
8622 CARB is 8622 heat treated to CARB — the intended service condition: hard wear/pitting-resistant case over a tough 30–40 HRC core for gears and pinions. 8622 CARB has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 91% of steel grades. Elongation at break is 11% and the elastic modulus is 205 GPa (29.7 Msi). 8622 CARB 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). A is the default condition FabDigit quotes; CARB is available on request or by drawing note.
Advantages
- High strength — 950 MPa (138 ksi), better than 91% of steel grades
Limitations
- Difficult to machine — 10/100, worse than 99% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
8622 CARB properties
Typical room-temperature values for 8622 CARB; 13 are specific to this condition. Other listed values are 8622 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8622 CARB 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
8622 CARB has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 91% of steel grades. Elongation at break is 11% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8622 CARB 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
8622 CARB 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 8622 CARB takes about 31 MJ of energy and emits 2.2 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
8622 CARB's machinability is not recommended (10/100, worse than 99% of steel grades); weldability not recommended (10/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8622 CARB
Is 8622 easy to machine?
Machine in the annealed or normalized state (~65 % of 1212) with carbide at 120–180 m/min; leave 0.2–0.4 mm grind stock for post-carburize distortion.
Can 8622 be welded?
Weldable with low-hydrogen consumables and 150–250 °C preheat plus post-weld stress relief; never weld carburized surfaces.
Can 8622 be formed, bent or molded?
Good hot forgeability at 1150–1250 °C followed by normalizing; cold bending limited in the cold-drawn temper.
What surface finishes work on 8622?
No anodizing — protect with black oxide, manganese phosphate, zinc plating or oil; carburized cases grind and superfinish well for gear flanks.
8622 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 | 0.2 – 0.25 | 0.22 |
| 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; 8622 resulfurized versions run higher | ≤ 0.04 | — |
| Fe | balance | — |
8622 CARB — frequently asked
What is 8622 CARB used for?
8622 CARB is typically used for gears, shafts and spline components. In short: stronger core than 8620; H-band grade available; gear and spline steel.
What is the yield strength of 8622 CARB?
8622 CARB has a typical yield strength of 950 MPa (138 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 8622 CARB easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Machine in the annealed or normalized state (~65 % of 1212) with carbide at 120–180 m/min; leave 0.2–0.4 mm grind stock for post-carburize distortion.
Can 8622 CARB be welded?
Not readily — weldability is rated not recommended (10/100). Weldable with low-hydrogen consumables and 150–250 °C preheat plus post-weld stress relief; never weld carburized surfaces.
What surface finishes work on 8622 CARB?
No anodizing — protect with black oxide, manganese phosphate, zinc plating or oil; carburized cases grind and superfinish well for gear flanks.
Can 8622 CARB be formed, bent or molded?
Good hot forgeability at 1150–1250 °C followed by normalizing; cold bending limited in the cold-drawn temper.
What is the maximum service temperature of 8622 CARB?
8622 CARB 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 8622-A and 8622 CARB?
A is the default condition — standard stocked condition for machining gear blanks before carburizing; softest and most stable. CARB: the intended service condition: hard wear/pitting-resistant case over a tough 30–40 HRC core for gears and pinions. Yield strength is 390 MPa in A versus 950 MPa in CARB.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — 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) — 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.