Steel 23B2
EN 23B2
23B2 (1.5508) is a medium-low carbon boron steel in the EN 10083/10250 alloy steel family, using boron rather than nickel or chromium to obtain hardenability for quench-and-temper treatment.
Reference datasheet — 23B2 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
23B2 tempers and conditions
23B2 is supplied in 6 conditions, soft to hard. +AC+C is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest condition, maximum cold-heading and extrusion capability before final sizing. | 300 | 450 | 25 | 128 HB | — |
Treated to ferrite-pearlite structure | Uniform ferrite-pearlite delivery condition when moderate strength plus reliable machining/heading of thicker sections is wanted. | 340 | 520 | 22 | 152 HB | — |
Hot rolled | Pick when the fastener maker will do its own spheroidizing or when only light upsetting/heading is needed. | 380 | 560 | 22 | 165 HB | — |
+AC+CDefault Spheroidize annealed and cold drawn | Standard stocked cold-heading wire: soft spheroidized structure sized by a light draw, ready for multi-station header feed. | 400 | 500 | 14 | 145 HB | — |
Untreated, cold drawn | Drawn-to-size bright bar/wire with better tolerance and surface for light heading, machining or direct hardening. | 560 | 650 | 10 | 195 HB | — |
Hardened and tempered | Final in-service condition of the finished part: water/oil quench from ~880 °C and temper 400–540 °C to reach class 8.8 strength. | 700 | 850 | 13 | 26 HRC | — |
What is 23B2?
23B2 (1.5508) is a medium-low carbon boron steel in the EN 10083/10250 alloy steel family, using boron rather than nickel or chromium to obtain hardenability for quench-and-temper treatment. It is chosen for cold-headed bolts, fasteners and pins needing moderate tempered strength and is stocked as annealed, spheroidized and cold-drawn wire and bar (+U, +AC, +AC+C, +TH). In the default condition it runs about 400 MPa yield, 500 MPa tensile, 14 % elongation and 145 HB, with high formability. It offers no corrosion resistance and boron increases HAZ hardenability; where higher strength after tempering is required, step up to 28B2 or 23MnB3. 23B2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). 23B2 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 60% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi).
What is 23B2 used for?
- bolts
- fasteners
- pins
Advantages
- Forms and bends easily — 88/100, better than 98% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Limited ductility — 14%, worse than 75% of steel grades
23B2 properties
Typical room-temperature values for 23B2-+AC+C; bars are the position among steel grades.
Physical3
23B2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical14
23B2 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 60% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
23B2 is rated for continuous service to 350°C (662 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
23B2 conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 23B2 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
23B2's machinability is good (60/100, better than 83% of steel grades); weldability very good (72/100); formability excellent (88/100).
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. 23B2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 23B2
Is 23B2 easy to machine?
Machines like a soft 1020/1023 — gummy in the spheroidized state; use sharp positive-rake tooling, good chip breaking, or machine after Q&T at ~25 HRC.
Can 23B2 be welded?
Weldable (CEV ≈ 0.30–0.35) with SMAW/GMAW, but boron sharply increases HAZ hardenability — preheat 100–150 °C on heavy sections and avoid welding hardened fasteners.
Can 23B2 be formed, bent or molded?
Designed for multi-station cold heading and cold extrusion in +AC or +AC+C; phosphate + soap or polymer lubricant coating, and inter-pass spheroidizing for very severe upsets.
23B2 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 |
| Si | ≤ 0.3 | 0.15 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Bboron for hardenability | 8×10⁻⁴ – 0.01 | 0 |
| Altotal Al (with Ti) to fix nitrogen so boron stays effective | ≥ 0.02 | 0.03 |
| Fe | balance |
What surface finishes work on 23B2?
No inherent corrosion resistance: zinc or zinc-nickel electroplate (with bake for hydrogen relief), zinc-flake dip-spin, or phosphate-and-oil; not anodizable.
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 23B2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5508
How much does 23B2 cost?
23B2 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
23B2 — frequently asked
What is 23B2 used for?
23B2 is typically used for bolts, fasteners and pins. In short: most formable boron grade; easier to weld than 23MnB3; low-cost cold-heading steel.
What is the yield strength of 23B2?
23B2 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 23B2 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like a soft 1020/1023 — gummy in the spheroidized state; use sharp positive-rake tooling, good chip breaking, or machine after Q&T at ~25 HRC.
Can 23B2 be welded?
Yes — weldability is rated very good (72/100). Weldable (CEV ≈ 0.30–0.35) with SMAW/GMAW, but boron sharply increases HAZ hardenability — preheat 100–150 °C on heavy sections and avoid welding hardened fasteners.
What surface finishes work on 23B2?
No inherent corrosion resistance: zinc or zinc-nickel electroplate (with bake for hydrogen relief), zinc-flake dip-spin, or phosphate-and-oil; not anodizable.
Can 23B2 be formed, bent or molded?
Designed for multi-station cold heading and cold extrusion in +AC or +AC+C; phosphate + soap or polymer lubricant coating, and inter-pass spheroidizing for very severe upsets.
What is the maximum service temperature of 23B2?
23B2 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 23B2 cost?
23B2 is a budget-cost steel ($), 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 10263-1/-2: Cold heading steels — general and delivery conditions — 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)
- ASTM A370 hardness conversion tables — ASTM (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.