Steel 15B2
EN 15B2
15B2 (1.5501) is a low-carbon boron steel from the EN 10083/10084 family that buys hardenability with a boron microaddition rather than costly alloying, supplied +U, +U+C, +A, +AC, +AC+C, +QT or CH.
Reference datasheet — 15B2 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
15B2 tempers and conditions
15B2 is supplied in 7 conditions, soft to hard. +AC+C 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Maximum cold-heading ductility — choose for severe multi-station upsetting or backward extrusion before drawing. | 250 | 400 | 32 | 115 HB | — |
Annealed | General soft condition for machining or moderate cold forming when full carbide spheroidizing is not required. | 265 | 420 | 28 | 120 HB | 11 % IACS |
Hot rolled | Cheapest mill condition for coils/bars that will be annealed or heat treated by the customer. | 300 | 460 | 24 | 135 HB | — |
+AC+CDefault Spheroidize annealed and cold drawn | Standard cold-heading wire condition: drawn to size and surface finish while keeping spheroidized ductility for fastener heading. | 420 | 520 | 13 | 155 HB | — |
Untreated then cold drawn | Pick when a straight, size-accurate bright bar with higher strength is needed and only light upsetting/machining follows. | 510 | 590 | 9 | 175 HB | — |
Quenched and tempered | Post-forming heat treatment where the boron addition pays off — small-diameter bolts/screws needing 800 MPa class strength. | 700 | 850 | 14 | 27 HRC | — |
Carburized and hardened | For self-tapping/self-drilling screws needing a hard wear-resistant case over a tough boron-hardened core. | 800 | 1,000 | 9 | 55 HRC | — |
What is 15B2?
15B2 (1.5501) is a low-carbon boron steel from the EN 10083/10084 family that buys hardenability with a boron microaddition rather than costly alloying, supplied +U, +U+C, +A, +AC, +AC+C, +QT or CH. The default condition gives 420 MPa yield, 520 MPa tensile, 13% elongation and 155 HB (82 HRB), with a formability score of 88/100 for cold-formed bolts, fasteners and case-hardened pins drawn from wire. Weldability is good (80/100) at CEV ≈ 0.25, but quenched-and-tempered parts soften in the HAZ and the steel has no corrosion resistance. 17B2 is the slightly higher-carbon alternative. 15B2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F). 15B2 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 53% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
What is 15B2 used for?
- bolts
- fasteners
- case-hardened 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
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Readily welded — 80/100, better than 79% 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
15B2 properties
Typical room-temperature values for 15B2-+AC+C; bars are the position among steel grades.
Physical3
15B2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F).
Mechanical15
15B2 has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 53% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
15B2 is rated for continuous service to 300°C (572 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
15B2 conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 15B2 takes about 27 MJ of energy and emits 2 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 30%.
Manufacturability6
15B2's machinability is good (55/100, better than 62% of steel grades); weldability very good (80/100); 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. 15B2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 15B2
Is 15B2 easy to machine?
Soft and gummy in +AC/+A; use sharp positive-rake tools, high speed and good chip breaking, or machine in the +C / +QT condition for better finish.
Can 15B2 be welded?
Weldable by resistance and MAG with CEV ≈ 0.25; on quenched-and-tempered parts the HAZ softens and boron-hardened zones can crack, so preheat and low hydrogen consumables are advised.
Can 15B2 be formed, bent or molded?
Excellent multi-station cold heading and extrusion in +AC+C; phosphate + soap or polymer lubricant, and allow inter-pass spheroidize anneal for very severe upsets.
15B2 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 |
|---|---|---|
| Clow carbon for cold heading | 0.12 – 0.18 | 0.15 |
| Sioften ≤0.10 for Si-killed cold-heading wire | ≤ 0.3 | 0.15 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Beffective (soluble) boron controls hardenability | 8×10⁻⁴ – 0.01 | 0 |
| Algrain refining / N fixing | 0.02 – 0.06 | 0.04 |
| Tiadded to tie up nitrogen and protect boron | ≤ 0.05 | 0.03 |
| Crresidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.3 | 0.08 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance |
What surface finishes work on 15B2?
No inherent corrosion resistance — zinc electroplate (with baking against hydrogen embrittlement), hot-dip galvanizing, zinc-flake coating or phosphate+oil are standard.
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 15B2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5501
How much does 15B2 cost?
15B2 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.
15B2 — frequently asked
What is 15B2 used for?
15B2 is typically used for bolts, fasteners and case-hardened pins. In short: cheapest hardenable fastener steel; excellent cold-heading formability; low CEV, weldable.
What is the yield strength of 15B2?
15B2 has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 15B2 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Soft and gummy in +AC/+A; use sharp positive-rake tools, high speed and good chip breaking, or machine in the +C / +QT condition for better finish.
Can 15B2 be welded?
Yes — weldability is rated very good (80/100). Weldable by resistance and MAG with CEV ≈ 0.25; on quenched-and-tempered parts the HAZ softens and boron-hardened zones can crack, so preheat and low hydrogen consumables are advised.
What surface finishes work on 15B2?
No inherent corrosion resistance — zinc electroplate (with baking against hydrogen embrittlement), hot-dip galvanizing, zinc-flake coating or phosphate+oil are standard.
Can 15B2 be formed, bent or molded?
Excellent multi-station cold heading and extrusion in +AC+C; phosphate + soap or polymer lubricant, and allow inter-pass spheroidize anneal for very severe upsets.
What is the maximum service temperature of 15B2?
15B2 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.
What is the difference between 15B2 +AC+C and 15B2-CH?
+AC+C is the default condition — standard cold-heading wire condition: drawn to size and surface finish while keeping spheroidized ductility for fastener heading. CH: for self-tapping/self-drilling screws needing a hard wear-resistant case over a tough boron-hardened core. Yield strength is 420 MPa in +AC+C versus 800 MPa in CH.
How much does 15B2 cost?
15B2 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: steels for quenching and tempering — CEN (2017)
- EN 10027-2 material number 1.5501 — CEN (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (boron steels) — ASM International (1990)
- ASM Handbook Vol.14A — Metalworking: Bulk Forming (cold heading) — ASM International (2005)
- Cold heading wire grades — boron steel (ML15B/15B21 class) technical data — wire rod producers (e.g. Ovako / Sandvik / ) (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.