Steel 94B17-HR (Hot rolled)
Supply condition · default condition
EN 94B17 · UNS G94171
Standard mill stock for gear blanks that will be machined then carburized.
Values for the HR 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 |
HRDefaultThis page 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-HR?
94B17-HR is 94B17 supplied in the HR condition — standard mill stock for gear blanks that will be machined then carburized. 94B17-HR 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). 94B17-HR 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).
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-HR properties
Typical room-temperature values for 94B17-HR; 22 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-HR 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-HR 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-HR 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-HR 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-HR 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-HR'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. Confirm any required mill or lot documentation when quoting.
Working with 94B17-HR
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-HR — frequently asked
What is 94B17-HR used for?
94B17-HR 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-HR?
94B17-HR 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-HR 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-HR 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-HR?
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-HR 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-HR?
94B17-HR 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.
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.