Steel 30MnB4
EN 30MnB4
30MnB4 (1.5526) is a boron-treated medium-carbon manganese steel in the EN 10083 alloy steel family, where the boron addition raises hardenability without the alloy content of a Cr-Mo grade.
Reference datasheet — 30MnB4 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
30MnB4 tempers and conditions
30MnB4 is supplied in 10 conditions, soft to hard. +QT 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Standard supply condition for cold-heading bolt wire: spheroidal carbides give maximum cold upsetting ductility. | 330 | 520 | 25 | 150 HB | 46 W/m·K |
Annealed | Sub-critical soft anneal for machining or intermediate processing; hardness capped by EN 10083-3. | 360 | 580 | 22 | 180 HB | 45 W/m·K |
Supplied with specified hardenability | Order this when quench response must be guaranteed — mill certifies a Jominy band (J1.5 typically ≈ 46–54 HRC); as-delivered condition is hot rolled or annealed and the part is hardened by the user. | 410 | 660 | 18 | 50 HRC | 9 % IACS |
Hot rolled | Mill-delivery hot-rolled coil for re-heating, hot forging or subsequent annealing lines. | 420 | 680 | 18 | 200 HB | — |
Normalized | Grain refinement after hot forging, used when parts are machined before hardening. | 450 | 720 | 17 | 215 HB | — |
Spheroidize annealed and cold drawn | Drawn-to-size cold-heading wire with clean surface and tight tolerance; slight work hardening over +AC but still headable. | 520 | 630 | 12 | 185 HB | — |
+QT | Property set for bars 16–40 mm where boron hardenability no longer gives full through-hardening. | 650 | 870 | 14 | 26 HRC | — |
+QTDefault Quenched and tempered | The workhorse condition: oil/polymer quench + temper ~430–500 °C for 10.9 bolts and high-strength machine parts up to ~16 mm section. | 980 | 1,100 | 12 | 34 HRC | 42 W/m·K |
quenched and low-temper, ≈1220–1400 MPa | Highest strength condition for small-diameter 12.9 fasteners; requires strict hydrogen and surface-decarburization control. | 1,150 | 1,300 | 9 | 41 HRC | — |
As quenched | Intermediate process state only — full hardness but brittle; must be tempered before service. | 1,400 | 1,750 | 2 | 50 HRC | 6.5 % IACS |
What is 30MnB4?
30MnB4 (1.5526) is a boron-treated medium-carbon manganese steel in the EN 10083 alloy steel family, where the boron addition raises hardenability without the alloy content of a Cr-Mo grade. Engineers choose it for quenched and tempered high-strength fasteners, and it is supplied mainly as cold heading quality wire, rod and bar. In the +QT default condition it reaches 980 MPa yield, 1100 MPa tensile, 12 % elongation and 330 HB (34 HRC), with 42 W/m·K conductivity and a 300 °C service ceiling. Hardenability is section-limited, weldability is poor and the bare steel has no corrosion resistance; 42CrMo4 is the usual alternative for larger diameters. 30MnB4 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). 30MnB4 has a yield strength of 980 MPa (142 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 91% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi).
What is 30MnB4 used for?
- high strength bolts
- fasteners
- shafts
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 980 MPa (142 ksi), better than 91% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
30MnB4 properties
Typical room-temperature values for 30MnB4-+QT; bars are the position among steel grades.
Physical3
30MnB4 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
30MnB4 has a yield strength of 980 MPa (142 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 91% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
30MnB4 is rated for continuous service to 300°C (572 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
30MnB4 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 30MnB4 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
30MnB4's machinability is fair (42/100, worse than 73% of steel grades); weldability fair (35/100); formability poor (20/100).
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. 30MnB4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 30MnB4
Is 30MnB4 easy to machine?
Best machined in +AC/+A (150–200 HB) with carbide inserts; at 34 HRC (+QT) cut speeds drop ~40 % and rigid setups plus coated carbide/CBN are needed — this is not a free-machining grade (low S).
Can 30MnB4 be welded?
Weldable with care only: CE ≈ 0.55, preheat 150–250 °C, low-hydrogen consumables and post-weld temper; boron promotes hard HAZ martensite and cold cracking, so welding of Q&T fasteners is normally avoided.
Can 30MnB4 be formed, bent or molded?
Designed for cold heading/upsetting in the spheroidized (+AC or +AC+C) state — phosphate + soap or polymer lubrication; hot forging 1100–1200 °C, austenitize 860–900 °C, oil/polymer quench, temper 400–500 °C for 10.9 (350–420 °C for 12.9), avoid 250–350 °C temper-embrittlement window.
30MnB4 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 |
|---|---|---|
| CEN 10083-3 | 0.27 – 0.33 | 0.3 |
| Simax; cold-heading grades often ≤0.30 | ≤ 0.4 | 0.2 |
| Mn | 0.8 – 1.1 | 0.95 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Beffective (soluble) boron controls hardenability; Ti/Al added to fix nitrogen | 8×10⁻⁴ – 0.01 | 0 |
| Fe | balance |
What surface finishes work on 30MnB4?
No corrosion resistance bare — zinc or zinc-nickel electroplate with mandatory 190–230 °C hydrogen bake within 4 h, or preferably mechanical/zinc-flake (Dacromet/Geomet) coating for ≥1000 MPa parts; phosphate + oil is common for automotive fasteners.
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 30MnB4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5526
How much does 30MnB4 cost?
30MnB4 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.
30MnB4 — frequently asked
What is 30MnB4 used for?
30MnB4 is typically used for high strength bolts, fasteners and shafts. In short: 10.9/12.9 fastener steel; boron hardenability, low alloy cost; cold-heading quality wire grade.
What is the yield strength of 30MnB4?
30MnB4 has a typical yield strength of 980 MPa (142 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 30MnB4 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Best machined in +AC/+A (150–200 HB) with carbide inserts; at 34 HRC (+QT) cut speeds drop ~40 % and rigid setups plus coated carbide/CBN are needed — this is not a free-machining grade (low S).
Can 30MnB4 be welded?
With care — weldability is rated fair (35/100). Weldable with care only: CE ≈ 0.55, preheat 150–250 °C, low-hydrogen consumables and post-weld temper; boron promotes hard HAZ martensite and cold cracking, so welding of Q&T fasteners is normally avoided.
What surface finishes work on 30MnB4?
No corrosion resistance bare — zinc or zinc-nickel electroplate with mandatory 190–230 °C hydrogen bake within 4 h, or preferably mechanical/zinc-flake (Dacromet/Geomet) coating for ≥1000 MPa parts; phosphate + oil is common for automotive fasteners.
Can 30MnB4 be formed, bent or molded?
Designed for cold heading/upsetting in the spheroidized (+AC or +AC+C) state — phosphate + soap or polymer lubrication; hot forging 1100–1200 °C, austenitize 860–900 °C, oil/polymer quench, temper 400–500 °C for 10.9 (350–420 °C for 12.9), avoid 250–350 °C temper-embrittlement window.
What is the maximum service temperature of 30MnB4?
30MnB4 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 30MnB4 cost?
30MnB4 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, Part 3: alloy steels — CEN (2006)
- EN 10263-4 — Steel rod, bars and wire for cold heading and cold extrusion, Part 4: quench and tempered steels — CEN (2017)
- 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)
- 30MnB4 / 1.5526 boron steel data sheet — Lucefin / Ovako (EN grade producers) (2020)
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.