Steel 23MnB4
EN 23MnB4
23MnB4 (1.5535) is a low-carbon boron-manganese steel from the EN 10083 alloy steel family, using boron to add hardenability while the modest carbon level keeps the wire headable.
Reference datasheet — 23MnB4 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 +AC+C condition
23MnB4 tempers and conditions
23MnB4 is supplied in 5 conditions, soft to hard. +AC+C is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest condition, spheroidized carbides for maximum cold-heading and deep-extrusion ability before drawing. | 320 | 480 | 24 | 145 HB | — |
Hot rolled | As-rolled coil or bar, the cheapest starting stock when the user will anneal or hot-form it themselves. | 380 | 570 | 20 | 170 HB | — |
+AC+CDefault Spheroidize annealed and cold drawn | The standard cold-heading wire condition: annealed then lightly drawn to size, phosphate-lubricated, ready for multi-station bolt formers. | 480 | 570 | 13 | 175 HB | — |
Untreated, cold drawn | Cold-drawn from as-rolled rod for tight tolerance and bright finish where only light upsetting or straight machining follows. | 580 | 660 | 10 | 200 HB | — |
Hardened and tempered | Final condition of the formed part: oil/polymer quenched and tempered, using the boron hardenability to reach 800–1100 MPa in small sections. | 880 | 1,000 | 12 | 32 HRC | — |
What is 23MnB4?
23MnB4 (1.5535) is a low-carbon boron-manganese steel from the EN 10083 alloy steel family, using boron to add hardenability while the modest carbon level keeps the wire headable. It is chosen for cold-headed and cold-extruded fasteners that are quenched and tempered after forming, and comes as CHQ wire, coil and bar in +U, +AC and spheroidized-plus-drawn conditions. As delivered it shows 480 MPa yield, 570 MPa tensile, 13 % elongation and 175 HB (88 HRB), with high formability (score 85) but only moderate machinability and weldability. It has no corrosion resistance; 27MnB4 is the step up when higher post-heat-treat strength is required. 23MnB4 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). 23MnB4 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 59% of steel grades. Elongation at break is 13% and the elastic modulus is 207 GPa (30 Msi).
What is 23MnB4 used for?
- fasteners
- bolts
- cold heading wire
Advantages
- Forms and bends easily — 85/100, better than 96% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited ductility — 13%, worse than 78% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
23MnB4 properties
Typical room-temperature values for 23MnB4-+AC+C; bars are the position among steel grades.
Physical3
23MnB4 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).
Mechanical15
23MnB4 has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 59% of steel grades. Elongation at break is 13% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
23MnB4 is rated for continuous service to 300°C (572 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
23MnB4 conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 23MnB4 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
23MnB4's machinability is good (60/100, better than 83% of steel grades); weldability fair (45/100); formability excellent (85/100).
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. 23MnB4 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 23MnB4
Is 23MnB4 easy to machine?
Machines like 1022/15B21 — free-cutting it is not; use sharp tools and good chip control in the annealed state, and expect ~45 % of 1212 rates once quenched and tempered.
Can 23MnB4 be welded?
Weldable with low-hydrogen consumables but boron plus CE ≈ 0.45–0.50 makes HAZ martensite likely; preheat 150–200 °C and post-weld temper, or avoid welding on hardened parts.
Can 23MnB4 be formed, bent or molded?
Designed for cold heading and extrusion in the +AC or +AC+C condition with zinc-phosphate + soap or polymer lubricant; keep reduction schedules moderate to avoid heading cracks.
23MnB4 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 | 0.2 – 0.25 | 0.23 |
| Simax per EN 10263-4 | ≤ 0.3 | 0.15 |
| Mn | 0.9 – 1.2 | 1.05 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Beffective boron; steel must be Al/Ti killed to protect it from N | 8×10⁻⁴ – 0.01 | 0 |
| Altotal Al, min for nitrogen fixing | ≥ 0.02 | 0.04 |
| Fe | balance |
What surface finishes work on 23MnB4?
No natural corrosion resistance — zinc electroplate (with 190–220 °C hydrogen bake above 1000 MPa), zinc-flake coating, or phosphate-and-oil are the usual finishes.
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 23MnB4 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5535
How much does 23MnB4 cost?
23MnB4 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
23MnB4 — frequently asked
What is 23MnB4 used for?
23MnB4 is typically used for fasteners, bolts and cold heading wire. In short: most formable boron fastener steel; cold-heading grade, heat treatable; lower carbon than 27MnB4.
What is the yield strength of 23MnB4?
23MnB4 has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 59% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 23MnB4 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like 1022/15B21 — free-cutting it is not; use sharp tools and good chip control in the annealed state, and expect ~45 % of 1212 rates once quenched and tempered.
Can 23MnB4 be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen consumables but boron plus CE ≈ 0.45–0.50 makes HAZ martensite likely; preheat 150–200 °C and post-weld temper, or avoid welding on hardened parts.
What surface finishes work on 23MnB4?
No natural corrosion resistance — zinc electroplate (with 190–220 °C hydrogen bake above 1000 MPa), zinc-flake coating, or phosphate-and-oil are the usual finishes.
Can 23MnB4 be formed, bent or molded?
Designed for cold heading and extrusion in the +AC or +AC+C condition with zinc-phosphate + soap or polymer lubricant; keep reduction schedules moderate to avoid heading cracks.
What is the maximum service temperature of 23MnB4?
23MnB4 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 23MnB4 cost?
23MnB4 is a budget-cost steel ($), 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 10263-4: Steel rod, bars and wire for cold heading and cold extrusion — Part 4: Steels for quenching and tempering — CEN (2018)
- EN 10083-3 / ISO 4954 boron steel chemistry references — CEN / ISO (2006)
- ISO 898-1 Mechanical properties of fasteners — property classes 8.8 / 10.9 — ISO (2013)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 14A: Metalworking — Bulk Forming (cold heading) — ASM International (2005)
- Cold heading wire rod grade datasheets (boron steels 19MnB4–37MnB5) — European wire rod producers (2022)
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.