Steel 30MnB5
EN 30MnB5
30MnB5 is a European medium-carbon manganese-boron steel (EN 10083-3 / EN 10263 boron grades) in which a small boron addition raises hardenability well above 20MnB4 without heavy alloying.
Reference datasheet — 30MnB5 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 +QT condition
30MnB5 tempers and conditions
30MnB5 is supplied in 8 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for cold heading, cold extrusion and severe upsetting of fastener blanks. | 350 | 570 | 22 | 175 HB | — |
Normalized | Use to refine grain and homogenise structure before machining or final hardening. | 430 | 680 | 18 | 14 HRC | 9 % IACS |
Hot rolled | Mill-supply condition of wire rod and bar before annealing or heat treatment. | 450 | 720 | 16 | 215 HB | — |
Cold drawn | Drawn-to-size wire or bright bar for cold heading lines and automatic machining. | 590 | 690 | 11 | 15 HRC | 8.5 % IACS |
+QTDefault Quenched and tempered | Standard delivered/finished strength condition for high-strength bolts, pins and wear parts. | 900 | 1,100 | 12 | 35 HRC | — |
Q&T to property class 10.9 | Fastener-specific temper for ISO 898-1 class 10.9 bolts and screws. | 980 | 1,100 | 11 | 35 HRC | — |
Q&T 40–45 HRC (low-temperature temper) | Pick where wear resistance and high strength matter more than toughness (tillage parts, links, pins). | 1,250 | 1,400 | 9 | 43 HRC | — |
Hardened | Intermediate condition only — full martensite, maximum hardness, must be tempered before service. | 1,400 | 1,800 | 3 | 50 HRC | 6.5 % IACS |
What is 30MnB5?
30MnB5 is a European medium-carbon manganese-boron steel (EN 10083-3 / EN 10263 boron grades) in which a small boron addition raises hardenability well above 20MnB4 without heavy alloying. It is supplied as cold-drawn wire, rod and bar for multi-station cold heading, and in the quenched-and-tempered default condition reaches 900 MPa yield, 1100 MPa tensile, 12% elongation and 330 HB (35 HRC), suiting property class 10.9 fasteners. Service is limited to about 300 °C, machinability is modest (score 40) and weldability is poor. Where welding is unavoidable, move to a lower-carbon boron grade such as 20MnB4. 30MnB5 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). 30MnB5 has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 90% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 30MnB5 used for?
- Property class 10.9 bolts and screws
- Cold-headed high-strength fasteners
- Wheel bolts and studs
- Chassis and suspension fasteners
- Socket-head cap screws
- Threaded rod and stud bolts
- Agricultural plough and track-shoe bolts
Advantages
- High strength — 900 MPa (131 ksi), better than 90% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
30MnB5 properties
Typical room-temperature values for 30MnB5-+QT; bars are the position among steel grades.
Physical3
30MnB5 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).
Mechanical16
30MnB5 has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 90% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
30MnB5 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 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
30MnB5 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 30MnB5 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
30MnB5's machinability is fair (40/100, worse than 77% of steel grades); weldability poor (30/100); 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. 30MnB5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 30MnB5
Is 30MnB5 easy to machine?
Machine in the annealed/cold-drawn state (~180–210 HB); at 33–39 HRC after Q&T use coated carbide, rigid setups and reduced feeds, or finish-grind.
Can 30MnB5 be welded?
Poor — CEV ~0.55–0.65 plus boron; if unavoidable use low-hydrogen consumables, 200–300 °C preheat and immediate stress relief, and expect a hard, crack-prone HAZ.
Can 30MnB5 be formed, bent or molded?
Designed for multi-station cold heading and extrusion in the spheroidize-annealed (≤207 HB) condition; hot forming 1100–850 °C, then normalize or re-anneal before Q&T.
30MnB5 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 | 0.27 – 0.33 | 0.3 |
| Sicold-heading grades often ≤0.30 | ≤ 0.4 | 0.2 |
| Mn | 1.15 – 1.45 | 1.3 |
| P | ≤ 0.03 | |
| S≤0.025 for cold-heading wire per EN 10263-4 | ≤ 0.04 | |
| Crresidual | ≤ 0.3 | 0.15 |
| Beffective (soluble) boron; Ti/Al added to fix nitrogen | 8×10⁻⁴ – 0.01 | 0 |
| Tinitrogen-fixing addition, producer practice | ≤ 0.05 | 0.03 |
| Fe | balance |
What surface finishes work on 30MnB5?
No inherent corrosion resistance — use zinc or zinc-nickel plating (bake 190–230 °C to relieve hydrogen), zinc-flake dip-spin, phosphate+oil or black oxide; avoid aggressive acid pickling on hardened parts.
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
How much does 30MnB5 cost?
30MnB5 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
30MnB5 — frequently asked
What is 30MnB5 used for?
30MnB5 is typically used for property class 10.9 bolts and screws, cold-headed high-strength fasteners, wheel bolts and studs, chassis and suspension fasteners, socket-head cap screws and threaded rod and stud bolts. In short: more hardenable than 20MnB4; class 10.9 cold-heading steel; poor weldability.
What is the yield strength of 30MnB5?
30MnB5 has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 30MnB5 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine in the annealed/cold-drawn state (~180–210 HB); at 33–39 HRC after Q&T use coated carbide, rigid setups and reduced feeds, or finish-grind.
Can 30MnB5 be welded?
Not readily — weldability is rated poor (30/100). Poor — CEV ~0.55–0.65 plus boron; if unavoidable use low-hydrogen consumables, 200–300 °C preheat and immediate stress relief, and expect a hard, crack-prone HAZ.
What surface finishes work on 30MnB5?
No inherent corrosion resistance — use zinc or zinc-nickel plating (bake 190–230 °C to relieve hydrogen), zinc-flake dip-spin, phosphate+oil or black oxide; avoid aggressive acid pickling on hardened parts.
Can 30MnB5 be formed, bent or molded?
Designed for multi-station cold heading and extrusion in the spheroidize-annealed (≤207 HB) condition; hot forming 1100–850 °C, then normalize or re-anneal before Q&T.
What is the maximum service temperature of 30MnB5?
30MnB5 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 30MnB5 cost?
30MnB5 is a budget-cost steel ($), 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
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- EN 10263-4 Steel rod, bars and wire for cold heading and cold extrusion — Steels for quenching and tempering — CEN (2018)
- ISO 898-1 Mechanical properties of fasteners — Bolts, screws and studs — ISO (2013)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Boron cold-heading steel wire rod datasheets (30MnB5 / 30MnB4) — European and Chinese wire-rod producers (2023)
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.