Steel 94B17 CARB
Heat-treated state
EN 94B17 · UNS G94171
CARB = carburized, quenched and tempered
The intended service condition: deep hardened case for gear tooth contact and bending fatigue with a tough, boron-hardened core.
Values for the CARB condition
Other 94B17 tempers and conditions
94B17 is listed in 7 conditions; see the grade overview at 94B17.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose for maximum cold formability, deep drilling or cold heading before carburizing. | 320 | 480 | 30 | 140 HB | 8 % IACS |
HRDefault Hot rolled | Standard mill stock for gear blanks that will be machined then carburized. | 380 | 550 | 25 | 160 HB | 7.8 % IACS |
Normalized | Use to homogenize forged blanks and refine grain before carburizing, giving more predictable distortion. | 410 | 620 | 22 | 180 HB | 7.6 % IACS |
Cold drawn | Pick for close-tolerance, straight bar with better surface finish for automatic-lathe parts. | 550 | 640 | 14 | 190 HB | 7.7 % IACS |
quenched and tempered (through-hardened, medium strength) | For shafts and sprockets used through-hardened rather than carburized, where toughness matters more than wear. | 780 | 950 | 17 | 29 HRC | — |
quenched and tempered (higher strength) | Higher-strength through-hardened condition for highly loaded shafts and fasteners; toughness starts to drop. | 970 | 1,150 | 14 | 35 HRC | — |
CARBThis page Carburized, quenched and tempered | The intended service condition: deep hardened case for gear tooth contact and bending fatigue with a tough, boron-hardened core. | 1,000 | 1,250 | 10 | 60 HRC | — |
What is 94B17 CARB?
94B17 CARB is 94B17 heat treated to CARB — the intended service condition: deep hardened case for gear tooth contact and bending fatigue with a tough, boron-hardened core. 94B17 CARB has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 92% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi). 94B17 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). HR is the default condition FabDigit quotes; CARB is available on request or by drawing note.
Advantages
- High strength — 1,000 MPa (145 ksi), better than 92% of steel grades
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
94B17 CARB properties
Typical room-temperature values for 94B17 CARB; 11 are specific to this condition. Other listed values are 94B17 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
94B17 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
94B17 CARB has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 92% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
94B17 CARB is rated for continuous service to 180°C (356 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
94B17 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 94B17 CARB takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
94B17 CARB's machinability is good (60/100, better than 83% of steel grades); weldability good (60/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 94B17 CARB
Is 94B17 easy to machine?
Machine in the annealed or normalized condition (≈65 % of AISI 1212) with carbide tooling; boron slightly raises hardness scatter, so hob and shape gear teeth before carburizing.
Can 94B17 be welded?
Weldable with low-hydrogen processes but boron plus Ni-Cr-Mo makes the HAZ air-hardening — preheat 150–250 °C, control interpass and PWHT/temper after welding.
Can 94B17 be formed, bent or molded?
Good cold heading and upsetting behaviour when spheroidize annealed; hot forge 1100–1200 °C and normalize afterwards to restore uniform boron hardenability.
What surface finishes work on 94B17?
Not anodizable; protect with zinc or manganese phosphate, black oxide, or Zn/Zn-Ni plating (bake to avoid hydrogen embrittlement on hardened parts); shot peening of carburized gear roots markedly improves bending fatigue.
94B17 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 |
|---|---|---|
| Cheat analysis, SAE J404 | 0.15 – 0.2 | 0.17 |
| Mn | 0.75 – 1 | 0.87 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.3 – 0.6 | 0.45 |
| Cr | 0.3 – 0.5 | 0.4 |
| Mo | 0.08 – 0.15 | 0.12 |
| BB designation; requires Ti/Al to fix free N | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.04 | — |
| Smax; resulfurized variants higher | ≤ 0.04 | — |
| Fe | balance | — |
94B17 CARB — frequently asked
What is 94B17 CARB used for?
94B17 CARB is typically used for carburized transmission gears, carburized shafts, differential pinion gears, planetary gear sets, splined drive shafts and gear-box pins and bushings. In short: deep case hardenability; boron-economised gear steel; air-hardening HAZ.
What is the yield strength of 94B17 CARB?
94B17 CARB has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,250 MPa (181 ksi) — stronger than 92% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 94B17 CARB easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machine in the annealed or normalized condition (≈65 % of AISI 1212) with carbide tooling; boron slightly raises hardness scatter, so hob and shape gear teeth before carburizing.
Can 94B17 CARB be welded?
Yes — weldability is rated good (60/100). Weldable with low-hydrogen processes but boron plus Ni-Cr-Mo makes the HAZ air-hardening — preheat 150–250 °C, control interpass and PWHT/temper after welding.
What surface finishes work on 94B17 CARB?
Not anodizable; protect with zinc or manganese phosphate, black oxide, or Zn/Zn-Ni plating (bake to avoid hydrogen embrittlement on hardened parts); shot peening of carburized gear roots markedly improves bending fatigue.
Can 94B17 CARB be formed, bent or molded?
Good cold heading and upsetting behaviour when spheroidize annealed; hot forge 1100–1200 °C and normalize afterwards to restore uniform boron hardenability.
What is the maximum service temperature of 94B17 CARB?
94B17 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 94B17-HR and 94B17 CARB?
HR is the default condition — standard mill stock for gear blanks that will be machined then carburized. CARB: the intended service condition: deep hardened case for gear tooth contact and bending fatigue with a tough, boron-hardened core. Yield strength is 380 MPa in HR versus 1,000 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, General Requirements — ASTM (2020)
- ASTM A304 — Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements — ASTM (2021)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4A: Steel Heat Treating Fundamentals and Processes (boron hardenability, carburizing) — ASM International (2013)
- 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.