Steel 34MnB5
EN 34MnB5
34MnB5 is a medium-carbon manganese-boron steel of the EN 10083 family in which the boron addition gives deep hardenability, allowing a full martensitic structure after in-die or oil quenching.
Values for the CR condition
34MnB5 tempers and conditions
34MnB5 is supplied in 7 conditions, soft to hard. CR 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 | Pick for maximum cold formability or for machining of thick blanks before hardening. | 340 | 560 | 22 | 165 HB | 8 % IACS |
CRDefault Cold rolled | Standard stocked condition: soft ferritic-pearlitic cold-rolled coil/blank for blanking and subsequent press hardening or Q&T. | 420 | 620 | 14 | 185 HB | — |
Hot rolled | Hot-rolled coil/plate for thicker press-hardened parts, wear plates and agricultural tool blanks before quenching. | 450 | 680 | 16 | 14 HRC | 8 % IACS |
Normalized | Uniform fine ferritic-pearlitic structure for moderate strength parts and as a pre-treatment before quench and temper. | 480 | 760 | 15 | 18 HRC | 8 % IACS |
Q&T 40-45 HRC | Higher tempering temperature for impact-loaded hardened components where 50+ HRC would be too brittle. | 1,150 | 1,350 | 11 | 42 HRC | — |
Pre-hardened | The end-use condition for hot-stamped structural/wear parts where ~2000 MPa strength and high hardness are required. | 1,400 | 1,950 | 4.5 | 53 HRC | — |
Q&T 48-52 HRC | Choose when hardened parts (plough shares, cutting edges, wear plates) need some toughness traded against peak hardness. | 1,400 | 1,650 | 8 | 50 HRC | — |
Supply forms, finishes and certifications
Ways 34MnB5 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
AS | Al-Si coated blank | Coating |
What is 34MnB5?
34MnB5 is a medium-carbon manganese-boron steel of the EN 10083 family in which the boron addition gives deep hardenability, allowing a full martensitic structure after in-die or oil quenching. It is supplied cold-rolled, hot-rolled, annealed, normalized, pre-hardened, quenched and tempered (QT42/QT50) or with Al-Si coating for hot stamping, and is used for press-hardened body structures and high-strength fasteners. As delivered it gives 420 MPa yield, 620 MPa tensile, 14 % elongation and 185 HB, with a 400 °C service limit. Hardened parts are effectively non-formable and have no corrosion resistance; 22MnB5 is the lower-carbon, more weldable alternative. 34MnB5 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). 34MnB5 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 53% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
What is 34MnB5 used for?
- Press-hardened B-pillar reinforcements
- Bumper beams
- Door impact beams
- Roof and rocker rails
- Floor and tunnel cross-members
- High-strength fasteners
- Blanks for direct hot stamping
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
34MnB5 properties
Typical room-temperature values for 34MnB5-CR; bars are the position among steel grades.
Physical3
34MnB5 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
34MnB5 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 53% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34MnB5 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
34MnB5 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 34MnB5 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
34MnB5's machinability is good (55/100, better than 62% of steel grades); weldability good (55/100); 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. 34MnB5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 34MnB5
Is 34MnB5 easy to machine?
Machine and drill in the soft as-delivered or annealed state; after press hardening (50+ HRC) use carbide/CBN, grinding or laser cutting only.
Can 34MnB5 be welded?
Weldable by RSW/laser in the soft state; boron raises hardenability so use low hydrogen consumables, preheat ~150–250 °C on thick sections, and expect HAZ softening/brittleness on hardened parts.
Can 34MnB5 be formed, bent or molded?
Cold form or blank only in the as-delivered condition; final geometry is normally produced by direct hot stamping at 900–950 °C with in-die quenching (>30 °C/s) — hardened parts are essentially non-formable.
Manufacturability
The process limits FabDigit applies to 34MnB5. Every 34MnB5 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Sheet metal
| Formability | Excellent60 / 100 |
|---|---|
| Weldability | Better55 / 100 |
34MnB5 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 |
|---|---|---|
| Chigh-carbon press-hardening variant | 0.3 – 0.37 | 0.34 |
| Si | 0.1 – 0.4 | 0.25 |
| Mn | 1 – 1.4 | 1.2 |
| P | ≤ 0.03 | |
| Smax (0.025 max on some hot-rolled deliveries) | ≤ 0.01 | |
| Cr | 0.1 – 0.35 | 0.2 |
| Altotal Al | 0.02 – 0.07 | 0.04 |
| Tities up N so B stays effective | 0.02 – 0.05 | 0.04 |
| Bhardenability booster | 0 – 0.01 | 0 |
| Fe | balance |
What surface finishes work on 34MnB5?
No anodizing; use Al-Si pre-coating for furnace protection, or shot blast plus zinc-phosphate/e-coat, zinc-flake or paint for corrosion protection.
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).
Plating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 34MnB5 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 34Mn B5
How much does 34MnB5 cost?
34MnB5 is a standard-cost steel ($$), cheaper than about 61% 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.
34MnB5 — frequently asked
What is 34MnB5 used for?
34MnB5 is typically used for press-hardened B-pillar reinforcements, bumper beams, door impact beams, roof and rocker rails, floor and tunnel cross-members and high-strength fasteners. In short: boron-bearing CR steel.
What is the yield strength of 34MnB5?
34MnB5 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 34MnB5 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine and drill in the soft as-delivered or annealed state; after press hardening (50+ HRC) use carbide/CBN, grinding or laser cutting only.
Can 34MnB5 be welded?
Yes — weldability is rated good (55/100). Weldable by RSW/laser in the soft state; boron raises hardenability so use low hydrogen consumables, preheat ~150–250 °C on thick sections, and expect HAZ softening/brittleness on hardened parts.
What surface finishes work on 34MnB5?
No anodizing; use Al-Si pre-coating for furnace protection, or shot blast plus zinc-phosphate/e-coat, zinc-flake or paint for corrosion protection.
Can 34MnB5 be formed, bent or molded?
Cold form or blank only in the as-delivered condition; final geometry is normally produced by direct hot stamping at 900–950 °C with in-die quenching (>30 °C/s) — hardened parts are essentially non-formable.
What is the maximum service temperature of 34MnB5?
34MnB5 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 34MnB5-CR and 34MnB5-PH?
CR is the default condition — standard stocked condition: soft ferritic-pearlitic cold-rolled coil/blank for blanking and subsequent press hardening or Q&T. PH: the end-use condition for hot-stamped structural/wear parts where ~2000 MPa strength and high hardness are required. Yield strength is 420 MPa in CR versus 1,400 MPa in PH.
How much does 34MnB5 cost?
34MnB5 is a standard-cost steel ($$), cheaper than about 61% 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.
Can FabDigit make parts in 34MnB5?
Yes — 34MnB5 is available for sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10083-3 Steels for quenching and tempering — alloy steels (boron grades) — CEN (2006)
- EN 10346 Continuously hot-dip / Al-Si coated flat steel products — CEN (2015)
- Press-hardening (hot-stamping) steel grades 22MnB5 / 30MnB5 / 34MnB5 data — ArcelorMittal / SSAB / voestalpine (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
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.