Steel 22MnB4 +AC+C
Supply condition · default condition
EN 22MnB4
+AC+C = spheroidize annealed and cold drawn
Standard stocked cold-heading wire condition: soft globular microstructure plus drawn size/finish for multi-station header feed.
Values for the +AC+C condition
Other 22MnB4 tempers and conditions
22MnB4 is listed in 6 conditions; see the grade overview at 22MnB4.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest condition, chosen when maximum cold-heading/extrusion ductility is needed before final drawing or forming. | 310 | 460 | 25 | 137 HB | — |
Hot rolled | Mill hot-rolled starting stock for further annealing, drawing or hot forging; cheapest form but limited cold formability. | 390 | 600 | 20 | 180 HB | — |
+AC+CDefaultThis page Spheroidize annealed and cold drawn | Standard stocked cold-heading wire condition: soft globular microstructure plus drawn size/finish for multi-station header feed. | 450 | 560 | 14 | 165 HB | — |
Cold drawn from the as-rolled condition | Drawn to size for bright bar / light upsetting where high as-drawn strength and tight tolerance matter more than deep cold heading. | 590 | 670 | 10 | 205 HB | — |
quenched and tempered to class 8.8-equivalent hardness | Higher-temperature temper (~540–600 °C) used when 8.8-class strength with better toughness and hydrogen-embrittlement margin is preferred. | 760 | 900 | 14 | 30 HRC | — |
Hardenability-guaranteed, quenched and tempered | Final condition of headed parts: oil/water quench from ~880 °C and temper ~420–500 °C to reach 10.9 fastener strength in sections up to ~16 mm. | 980 | 1,100 | 11 | 35 HRC | — |
What is 22MnB4 +AC+C?
22MnB4 +AC+C is 22MnB4 supplied in the +AC+C condition — standard stocked cold-heading wire condition: soft globular microstructure plus drawn size/finish for multi-station header feed. 22MnB4 +AC+C has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 52% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). 22MnB4 +AC+C 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).
Advantages
- Forms and bends easily — 82/100, better than 94% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited ductility — 14%, worse than 75% of steel grades
22MnB4 +AC+C properties
Typical room-temperature values for 22MnB4 +AC+C; 15 are specific to this condition. Other listed values are 22MnB4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
22MnB4 +AC+C 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
22MnB4 +AC+C has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 52% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
22MnB4 +AC+C 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 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
22MnB4 +AC+C conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 22MnB4 +AC+C takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
22MnB4 +AC+C's machinability is good (55/100, better than 62% of steel grades); weldability good (60/100); formability very good (82/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 22MnB4 +AC+C
Is 22MnB4 easy to machine?
Machines like a 1022/1524-type carbon steel (~60 % of AISI 1212) in +AC or +AC+C; after quench-and-temper to 35 HRC use coated carbide, reduced speed, or grind.
Can 22MnB4 be welded?
Weldable with care (CE_IIW ≈ 0.45–0.55): preheat 100–150 °C, low-hydrogen consumables and PWHT for thick sections; welding after hardening destroys the tempered strength and boron benefit locally.
Can 22MnB4 be formed, bent or molded?
Excellent multi-station cold heading and cold extrusion in the +AC / +AC+C condition with phosphate + soap or polymer lubricant; hot forging 1100–1200 °C, austenitize 870–900 °C, oil or water quench, temper 420–600 °C to target class.
What surface finishes work on 22MnB4?
No corrosion resistance bare — zinc electroplate (with mandatory 200 °C/4 h bake at 10.9 to avoid hydrogen embrittlement), zinc-flake dip-spin, phosphate + oil, or hot-dip galvanizing on lower classes.
22MnB4 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 10263-4 / EN 10083-3 | 0.2 – 0.25 | 0.22 |
| Si | ≤ 0.3 | 0.15 |
| Mn | 0.9 – 1.2 | 1.05 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Beffective (soluble) boron controls hardenability | 8×10⁻⁴ – 0.01 | 0 |
| Titypical N-fixing addition to protect soluble B | 0.02 – 0.05 | 0.04 |
| Algrain refinement / deoxidation | 0.02 – 0.06 | 0.04 |
| Crresidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.3 | 0.08 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance | — |
22MnB4 +AC+C — frequently asked
What is 22MnB4 +AC+C used for?
22MnB4 +AC+C is typically used for high strength bolts, fasteners and cold heading wire. In short: class 10.9 boron fastener steel; deep hardenability, low alloy cost; requires bake after plating.
What is the yield strength of 22MnB4 +AC+C?
22MnB4 +AC+C has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 560 MPa (81.2 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 22MnB4 +AC+C easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a 1022/1524-type carbon steel (~60 % of AISI 1212) in +AC or +AC+C; after quench-and-temper to 35 HRC use coated carbide, reduced speed, or grind.
Can 22MnB4 +AC+C be welded?
Yes — weldability is rated good (60/100). Weldable with care (CE_IIW ≈ 0.45–0.55): preheat 100–150 °C, low-hydrogen consumables and PWHT for thick sections; welding after hardening destroys the tempered strength and boron benefit locally.
What surface finishes work on 22MnB4 +AC+C?
No corrosion resistance bare — zinc electroplate (with mandatory 200 °C/4 h bake at 10.9 to avoid hydrogen embrittlement), zinc-flake dip-spin, phosphate + oil, or hot-dip galvanizing on lower classes.
Can 22MnB4 +AC+C be formed, bent or molded?
Excellent multi-station cold heading and cold extrusion in the +AC / +AC+C condition with phosphate + soap or polymer lubricant; hot forging 1100–1200 °C, austenitize 870–900 °C, oil or water quench, temper 420–600 °C to target class.
What is the maximum service temperature of 22MnB4 +AC+C?
22MnB4 +AC+C 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.
Sources
- EN 10263-4 Steel rod, bars and wire for cold heading and cold extrusion – Part 4: heat treatable steels — CEN (2018)
- EN 10083-3 Steels for quenching and tempering – Part 3: alloy steels — CEN (2006)
- ISO 898-1 Mechanical properties of fasteners – bolts, screws and studs (property class 10.9) — ISO (2013)
- GB/T 6478 / GB/T 3077 ( 20MnTiB/22MnB ) — SAC (2015)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 – Heat Treating (boron hardenability) — ASM International (1991)
- Cold heading wire rod 22MnB4 datasheets — Ovako / Saarstahl / voestalpine (2022)
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.