Steel 8627 CARB
Heat-treated state
AISI/SAE 8627 · UNS G86270
CARB = carburized & hardened
Primary intended use: hard wear-resistant case (58–62 HRC) over a tough, higher-strength core than 8620.
Values for the CARB condition
Other 8627 tempers and conditions
8627 is listed in 10 conditions; see the grade overview at 8627.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Softest and most machinable condition; standard supply state for bar that will be machined then carburized. | 380 | 560 | 30 | 156 HB | — |
Hot rolled | Cheapest mill condition for parts that will be fully heat treated after rough machining. | 400 | 640 | 24 | 185 HB | — |
Normalized | Uniform fine-grained structure with better core toughness and machined-surface finish before carburizing. | 430 | 690 | 25 | 195 HB | — |
Cold drawn | Tight-tolerance bright bar with raised yield strength for shafts and pins machined with light stock removal. | 620 | 720 | 15 | 217 HB | — |
Q&T 650 °C | Softest Q&T condition, maximum toughness and ductility for shock-loaded or later-machined parts. | 635 | 795 | 23 | 22 HRC | — |
CARBThis page Carburized & hardened | Primary intended use: hard wear-resistant case (58–62 HRC) over a tough, higher-strength core than 8620. | 790 | 1,030 | 13 | 60 HRC | — |
Q&T 540 °C | Pick the oil quenched, 540 °C tempered state (~28–32 HRC) for machined shafts and tough cores, giving 830 MPa yield and 18% elongation with moderate machinability. | 830 | 965 | 18 | 30 HRC | — |
Q&T 425 °C | Balanced strength/toughness around 36–38 HRC for shafts and highly loaded fasteners. | 1,000 | 1,170 | 14 | 38 HRC | — |
Q&T 315 °C | High strength with slightly improved ductility; avoid this range if temper embrittlement/impact toughness matters. | 1,170 | 1,380 | 11 | 43 HRC | — |
Q&T 205 °C | Maximum through-hardened strength for wear parts where impact loading is low. | 1,240 | 1,500 | 10 | 46 HRC | — |
What is 8627 CARB?
8627 CARB is 8627 heat treated to CARB — primary intended use: hard wear-resistant case (58–62 HRC) over a tough, higher-strength core than 8620. 8627 CARB has a yield strength of 790 MPa (115 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). 8627 CARB 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). A is the default condition FabDigit quotes; CARB is available on request or by drawing note.
Advantages
- High strength — 790 MPa (115 ksi), better than 86% of steel grades
Limitations
- Limited service temperature — 160°C (320 °F), worse than 99% of steel grades
- Difficult to machine — 10/100, worse than 99% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
8627 CARB properties
Typical room-temperature values for 8627 CARB; 12 are specific to this condition. Other listed values are 8627 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8627 CARB 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).
Mechanical13
8627 CARB has a yield strength of 790 MPa (115 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8627 CARB is rated for continuous service to 160°C (320 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
8627 CARB conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 8627 CARB takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 35%.
Manufacturability7
8627 CARB's machinability is not recommended (10/100, worse than 99% of steel grades); weldability fair (52/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8627 CARB
Is 8627 easy to machine?
Machines well annealed or normalized (~60–65 % of 1212) with carbide tooling; rough machine before carburizing and finish-grind the hardened case.
Can 8627 be welded?
Weldable with low-hydrogen consumables but the ~0.27 % C and Ni-Cr-Mo content require 200–300 °C preheat and post-weld stress relief/temper; do not weld after carburizing.
Can 8627 be formed, bent or molded?
Hot forge 1100–1200 °C with slow cooling or normalizing afterwards; cold forming limited to mild bending in the annealed condition.
What surface finishes work on 8627?
No anodizing — protect bare surfaces with black oxide, manganese phosphate, zinc or nickel plating; bake after plating to avoid hydrogen embrittlement when hardened.
8627 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 |
|---|---|---|
| C | 0.25 – 0.3 | 0.27 |
| 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/resulfurized variants differ | ≤ 0.04 | — |
| Fe | balance | — |
8627 CARB — frequently asked
What is 8627 CARB used for?
8627 CARB is typically used for gears, shafts, axle components and heavy fasteners. In short: higher core strength carburizing; between 8625 and 8630; medium-section hardenability.
What is the yield strength of 8627 CARB?
8627 CARB has a typical yield strength of 790 MPa (115 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 8627 CARB easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Machines well annealed or normalized (~60–65 % of 1212) with carbide tooling; rough machine before carburizing and finish-grind the hardened case.
Can 8627 CARB be welded?
With care — weldability is rated fair (52/100). Weldable with low-hydrogen consumables but the ~0.27 % C and Ni-Cr-Mo content require 200–300 °C preheat and post-weld stress relief/temper; do not weld after carburizing.
What surface finishes work on 8627 CARB?
No anodizing — protect bare surfaces with black oxide, manganese phosphate, zinc or nickel plating; bake after plating to avoid hydrogen embrittlement when hardened.
Can 8627 CARB be formed, bent or molded?
Hot forge 1100–1200 °C with slow cooling or normalizing afterwards; cold forming limited to mild bending in the annealed condition.
What is the maximum service temperature of 8627 CARB?
8627 CARB is rated for continuous use to about 160°C (320 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8627-A and 8627-QT205?
A is the default condition — softest and most machinable condition; standard supply state for bar that will be machined then carburized. QT205: maximum through-hardened strength for wear parts where impact loading is low. Yield strength is 380 MPa in A versus 1,240 MPa in QT205.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — 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 — ASM International (1991)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
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.