Steel 94B17
EN 94B17 · UNS G94171
94B17 is a low-carbon nickel-chromium-molybdenum case-hardening steel with a boron addition (SAE 94BXX family, UNS G94171) used where deep case hardenability is required after carburizing.
Reference datasheet — 94B17 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 HR condition
94B17 tempers and conditions
94B17 is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
94B17 is a low-carbon nickel-chromium-molybdenum case-hardening steel with a boron addition (SAE 94BXX family, UNS G94171) used where deep case hardenability is required after carburizing. It is stocked as hot-rolled, annealed, normalized and cold-drawn bar, machined soft at roughly 380 MPa yield, 550 MPa tensile, 25 % elongation and 160 HB, then carburized and quench-tempered to 26–32 HRC or 32–38 HRC. Boron plus Ni-Cr-Mo makes the HAZ air-hardening, so welding needs preheat and post-weld temper, and the steel has no corrosion resistance of its own. 8620 is the usual alternative when the extra boron hardenability is not needed. 94B17 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). 94B17 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 68% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
What is 94B17 used for?
- Carburized transmission gears
- Carburized shafts
- Differential pinion gears
- Planetary gear sets
- Splined drive shafts
- Gear-box pins and bushings
- Chain sprockets
Advantages
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
94B17 properties
Typical room-temperature values for 94B17-HR; bars are the position among steel grades.
Physical3
94B17 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 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 68% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
94B17 is rated for continuous service to 300°C (572 °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 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 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's machinability is good (60/100, better than 83% of steel grades); weldability good (60/100); formability good (60/100).
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. 94B17 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 94B17
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.
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 |
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.
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 94B17 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G94171
How much does 94B17 cost?
94B17 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.
94B17 — frequently asked
What is 94B17 used for?
94B17 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?
94B17 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 94B17 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 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?
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 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?
94B17 is rated for continuous use to about 300°C (572 °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.
How much does 94B17 cost?
94B17 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)
- 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; 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.