Steel 94B30
EN 94B30 · UNS G94301
94B30 is a medium-carbon nickel-chromium-molybdenum steel with a boron addition (SAE 94BXX family, UNS G94301) intended for through-hardened rather than carburized parts.
Reference datasheet — 94B30 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 QT540 condition
94B30 tempers and conditions
94B30 is supplied in 10 conditions, soft to hard. QT540 is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Choose for cold heading, deep machining or wire drawing before quench-and-temper. | 380 | 570 | 24 | 170 HB | — |
Hot rolled | Mill supply condition for bar/coil that will be hot-forged and then heat treated by the part maker. | 430 | 700 | 20 | 15 HRC | 8.2 % IACS |
Normalized | Used to refine forging structure and homogenize before final hardening. | 480 | 760 | 19 | 19 HRC | 8 % IACS |
Cold drawn | Pick when tight size tolerance and a good machined finish are needed prior to heat treatment. | 660 | 760 | 13 | 19 HRC | 8 % IACS |
Q&T 650 °C | Softest Q&T condition — pick for maximum toughness, machining of large sections, or where later welding is planned. | 700 | 830 | 21 | 24 HRC | — |
QT540Default Q&T 540 °C | Most commonly stocked/specified condition: good toughness with ~1000 MPa tensile, still readily machinable. | 860 | 990 | 17 | 30 HRC | — |
Q&T 425 °C | Balanced strength/toughness for heavily loaded automotive shafts and Grade 8-class fasteners. | 1,080 | 1,190 | 15 | 37 HRC | — |
Q&T 315 °C | High-strength condition for shafts and fasteners needing more toughness than the 205 °C temper. | 1,270 | 1,400 | 12 | 43 HRC | — |
As-Quenched | Intermediate condition only — full martensite, must be tempered before service to avoid quench cracking. | 1,350 | 1,800 | 5 | 52 HRC | 6.6 % IACS |
Q&T 205 °C | Maximum strength/wear condition for pins, links and wear parts where toughness demand is low. | 1,420 | 1,620 | 10 | 48 HRC | — |
What is 94B30?
94B30 is a medium-carbon nickel-chromium-molybdenum steel with a boron addition (SAE 94BXX family, UNS G94301) intended for through-hardened rather than carburized parts. In the default quenched-and-tempered condition it provides 860 MPa yield, 990 MPa tensile, 17 % elongation and 293 HB (30 HRC), with temper steps on file from QT205 to QT650 and a maximum service temperature of 400 °C; machinability is rated 45. Weldability is the main limit — the martensitic HAZ requires 200–300 °C preheat and post-weld temper — and there is no inherent corrosion resistance. 8630 or 4140 are the closest alternatives. 94B30 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). 94B30 has a yield strength of 860 MPa (125 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 89% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
What is 94B30 used for?
- axle shafts
- high-strength bolts
- structural parts
Advantages
- High strength — 860 MPa (125 ksi), better than 89% of steel grades
94B30 properties
Typical room-temperature values for 94B30-QT540; bars are the position among steel grades.
Physical3
94B30 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).
Mechanical15
94B30 has a yield strength of 860 MPa (125 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 89% of steel grades. Elongation at break is 17% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
94B30 is rated for continuous service to 400°C (752 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
94B30 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 94B30 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
94B30's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (35/100); formability fair (35/100).
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. 94B30 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 94B30
Is 94B30 easy to machine?
Machine in the annealed or ≤32 HRC Q&T condition with carbide at moderate speed and heavy positive feed; above 40 HRC use coated carbide/CBN or grind.
Can 94B30 be welded?
Weldable with low-hydrogen consumables only with 200–300 °C preheat and post-weld temper; the martensitic HAZ is crack-prone and boron hardenability makes cooling-rate control critical.
Can 94B30 be formed, bent or molded?
Cold head, upset or bend in the spheroidize-annealed condition; hot forge at 1100–1200 °C and normalize before hardening to restore grain size.
94B30 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 | 0.28 – 0.33 | 0.3 |
| Mn | 0.75 – 1 | 0.88 |
| 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 |
| Bhardenability agent; requires Ti/Al nitrogen fixation to stay effective | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.04 | |
| S | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 94B30?
No anodizing — protect with zinc or zinc-nickel plating (bake for hydrogen relief above 1000 MPa), manganese phosphate + oil, Zn-flake dip-spin, or paint.
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 94B30 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G94301
How much does 94B30 cost?
94B30 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.
94B30 — frequently asked
What is 94B30 used for?
94B30 is typically used for axle shafts, high-strength bolts and structural parts. In short: through-hardening boron grade; 990 MPa quench-and-temper strength; preheat-dependent weldability.
What is the yield strength of 94B30?
94B30 has a typical yield strength of 860 MPa (125 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 89% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 94B30 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed or ≤32 HRC Q&T condition with carbide at moderate speed and heavy positive feed; above 40 HRC use coated carbide/CBN or grind.
Can 94B30 be welded?
With care — weldability is rated fair (35/100). Weldable with low-hydrogen consumables only with 200–300 °C preheat and post-weld temper; the martensitic HAZ is crack-prone and boron hardenability makes cooling-rate control critical.
What surface finishes work on 94B30?
No anodizing — protect with zinc or zinc-nickel plating (bake for hydrogen relief above 1000 MPa), manganese phosphate + oil, Zn-flake dip-spin, or paint.
Can 94B30 be formed, bent or molded?
Cold head, upset or bend in the spheroidize-annealed condition; hot forge at 1100–1200 °C and normalize before hardening to restore grain size.
What is the maximum service temperature of 94B30?
94B30 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 94B30-QT540 and 94B30-QT205?
QT540 is the default condition — most commonly stocked/specified condition: good toughness with ~1000 MPa tensile, still readily machinable. QT205: maximum strength/wear condition for pins, links and wear parts where toughness demand is low. Yield strength is 860 MPa in QT540 versus 1,420 MPa in QT205.
How much does 94B30 cost?
94B30 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 — ASTM International (2020)
- 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 — ASM International (2013)
- SAE J417 — Hardness Tests and Hardness Number Conversions — SAE International (2018)
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.