Steel 34MnB5 · finish state
Steel 34MnB5-AS
Properties of the AS condition, compared with the other 34MnB5 tempers.
Aluminium-silicon coated coil/blank: prevents scaling and decarburisation in the austenitizing furnace and gives moderate in-service corrosion protection after press hardening.
What is 34MnB5-AS?
34MnB5-AS is 34MnB5 supplied in the AS condition — aluminium-silicon coated coil/blank: prevents scaling and decarburisation in the austenitizing furnace and gives moderate in-service corrosion protection after press hardening. 34MnB5-AS has a yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 96% of steel grades. Elongation at break is 4.5% and the elastic modulus is 210 GPa (30.5 Msi). 34MnB5-AS 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). CR is the default condition FabDigit quotes; AS is available on request or by drawing note.
Advantages
- High strength — 1,400 MPa (203 ksi), better than 96% of steel grades
- Good corrosion resistance — 30/100, better than 95% of steel grades
Limitations
- Limited formability — 5/100, worse than 99% of steel grades
- Limited ductility — 4.5%, worse than 98% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 83% of steel grades
34MnB5-AS properties
Typical room-temperature values for 34MnB5-AS — 9 properties are specific to this condition; the rest are grade-level values shared by every 34MnB5 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
34MnB5-AS 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-AS has a yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 96% of steel grades. Elongation at break is 4.5% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34MnB5-AS is rated for continuous service to 200°C (392 °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-AS conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), better than 95% of steel grades.
Sustainability4
Producing a kilogram of 34MnB5-AS 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-AS's machinability is good (55/100, better than 62% of steel grades); weldability fair (35/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 34MnB5 tempers and conditions
34MnB5 is also supplied in 7 other conditions. The full side-by-side table is on the 34MnB5 overview.
- CRDefaultStandard stocked condition: soft ferritic-pearlitic cold-rolled coil/blank for blanking and subsequent press hardening or Q&T.420 MPa yield · 185 HB
- PHThe end-use condition for hot-stamped structural/wear parts where ~2000 MPa strength and high hardness are required.1,400 MPa yield · 53 HRC
- QT50Choose when hardened parts (plough shares, cutting edges, wear plates) need some toughness traded against peak hardness.1,400 MPa yield · 50 HRC
- ASAluminium-silicon coated coil/blank: prevents scaling and decarburisation in the austenitizing furnace and gives moderate in-service corrosion protection after press hardening.1,400 MPa yield · 53 HRC
- QT42Higher tempering temperature for impact-loaded hardened components where 50+ HRC would be too brittle.1,150 MPa yield · 42 HRC
- NUniform fine ferritic-pearlitic structure for moderate strength parts and as a pre-treatment before quench and temper.480 MPa yield · 220 HB
- HRHot-rolled coil/plate for thicker press-hardened parts, wear plates and agricultural tool blanks before quenching.450 MPa yield · 200 HB
- APick for maximum cold formability or for machining of thick blanks before hardening.340 MPa yield · 165 HB
Working with 34MnB5-AS
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.
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.
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 | — |
34MnB5-AS — frequently asked
What is 34MnB5-AS used for?
34MnB5-AS 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-AS?
34MnB5-AS has a typical yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 96% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 34MnB5-AS 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-AS be welded?
With care — weldability is rated fair (35/100). 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-AS?
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-AS 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-AS?
34MnB5-AS is rated for continuous use to about 200°C (392 °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.
Can FabDigit make parts in 34MnB5-AS?
Yes — 34MnB5-AS is available for sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.