Steel 18B2
EN 18B2
18B2 (1.5503) is a low-carbon boron-treated alloy steel from the EN 10083/10250 alloy steel family, where a small boron addition provides through-hardening without heavy alloy content.
Reference datasheet — 18B2 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
18B2 tempers and conditions
18B2 is supplied in 8 conditions, soft to hard. +AC+C is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest state, used as the input for the most severe multi-station cold extrusion and deep upsetting. | 270 | 430 | 30 | 130 HB | — |
Annealed | General soft state for machining or moderate forming when full spheroidization is not required. | 300 | 460 | 28 | 140 HB | 10 % IACS |
Hot rolled | Cheapest supply state for parts that will be re-heated, hot forged or annealed by the customer. | 350 | 540 | 24 | 160 HB | — |
+AC+CDefault Spheroidize annealed and cold drawn | Standard stocked condition for bolt/screw wire: soft spheroidized structure with drawn size tolerance and lubricant carrier. | 430 | 520 | 14 | 155 HB | — |
Untreated and cold drawn | Pick for straight, on-size bright bar with higher strength when only light upsetting or plain machining follows. | 550 | 640 | 10 | 190 HB | — |
+QT | Post-heading through-hardening route for M5–M16 class 8.8 bolts and screws where boron gives full hardenability at low cost. | 700 | 860 | 14 | 27 HRC | — |
Carburized and hardened | For self-tapping/self-drilling screws and small wear parts needing a 550–750 HV case over a tough boron-hardened core. | 700 | 900 | 9 | 58 HRC | — |
+QT | Lower tempering temperature for small-diameter high-strength fasteners; watch hydrogen embrittlement after plating. | 820 | 960 | 12 | 31 HRC | 9 % IACS |
What is 18B2?
18B2 (1.5503) is a low-carbon boron-treated alloy steel from the EN 10083/10250 alloy steel family, where a small boron addition provides through-hardening without heavy alloy content. Engineers select it for cold-headed fasteners, pins and case-hardened parts that must reach property class 8.8 or 9.8 after quenching and tempering; it is normally supplied as annealed or cold-drawn wire and bar (+U, +AC, +AC+C). In the default condition it runs about 430 MPa yield, 520 MPa tensile, 14 % elongation and 155 HB. It has no inherent corrosion resistance and boron sharply raises HAZ hardenability, so where higher tempered strength is required 23B2 or 28B2 is the nearer choice. 18B2 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). 18B2 has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 51% of steel grades. Elongation at break is 14% and the elastic modulus is 207 GPa (30 Msi).
What is 18B2 used for?
- fasteners
- pins
- case-hardened components
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
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
Limitations
- Limited ductility — 14%, worse than 75% of steel grades
18B2 properties
Typical room-temperature values for 18B2-+AC+C; bars are the position among steel grades.
Physical3
18B2 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).
Mechanical14
18B2 has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 51% of steel grades. Elongation at break is 14% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
18B2 is rated for continuous service to 350°C (662 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
18B2 conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 18B2 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
18B2's machinability is good (60/100, better than 83% of steel grades); weldability good (65/100); formability very good (82/100).
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. 18B2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 18B2
Is 18B2 easy to machine?
Machines like a soft low-alloy steel (~65 % of 1212); spheroidized material is gummy — use sharp positive tooling and good chip breaking, or specify the cold-drawn condition for better finish.
Can 18B2 be welded?
Weldable by MAG/resistance methods at CEV ≈0.35, but boron sharply raises HAZ hardenability — use low-hydrogen consumables and preheat 100–150 °C on heavier sections; avoid welding parts already quenched and tempered.
Can 18B2 be formed, bent or molded?
Excellent cold heading/extrusion in +AC or +AC+C with phosphate + soap or polymer lubricant carrier; strain-hardening is moderate, so 3–5 station forming of class 8.8 blanks is routine.
18B2 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 | 0.15 – 0.2 | 0.18 |
| Silow Si for formability; Al-killed grades often Si ≤0.10 | ≤ 0.3 | 0.15 |
| Mn | 0.5 – 0.9 | 0.7 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Beffective (soluble) boron controls hardenability | 8×10⁻⁴ – 0.01 | 0 |
| Algrain refining / nitrogen fixing | 0.02 – 0.06 | 0.04 |
| Tioptional, added to tie up free N and protect the boron effect | ≤ 0.05 | 0.03 |
| Crresidual | ≤ 0.3 | |
| Niresidual | ≤ 0.3 | |
| Curesidual | ≤ 0.25 | |
| Nmax; free N must be low | ≤ 0.01 | |
| Fe | balance |
What surface finishes work on 18B2?
No natural corrosion resistance: zinc or zinc-nickel electroplate (bake 190–220 °C for ≥4 h after plating on ≥1000 MPa parts), zinc-flake (Dacromet/Geomet) for hydrogen-free protection, or phosphate + oil for interim storage.
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 18B2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5503
How much does 18B2 cost?
18B2 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.
18B2 — frequently asked
What is 18B2 used for?
18B2 is typically used for fasteners, pins and case-hardened components. In short: low-cost boron fastener steel; excellent cold-heading formability; case- or through-hardenable.
What is the yield strength of 18B2?
18B2 has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 51% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 18B2 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like a soft low-alloy steel (~65 % of 1212); spheroidized material is gummy — use sharp positive tooling and good chip breaking, or specify the cold-drawn condition for better finish.
Can 18B2 be welded?
Yes — weldability is rated good (65/100). Weldable by MAG/resistance methods at CEV ≈0.35, but boron sharply raises HAZ hardenability — use low-hydrogen consumables and preheat 100–150 °C on heavier sections; avoid welding parts already quenched and tempered.
What surface finishes work on 18B2?
No natural corrosion resistance: zinc or zinc-nickel electroplate (bake 190–220 °C for ≥4 h after plating on ≥1000 MPa parts), zinc-flake (Dacromet/Geomet) for hydrogen-free protection, or phosphate + oil for interim storage.
Can 18B2 be formed, bent or molded?
Excellent cold heading/extrusion in +AC or +AC+C with phosphate + soap or polymer lubricant carrier; strain-hardening is moderate, so 3–5 station forming of class 8.8 blanks is routine.
What is the maximum service temperature of 18B2?
18B2 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.
What is the difference between 18B2 +AC+C and 18B2-CH?
+AC+C is the default condition — standard stocked condition for bolt/screw wire: soft spheroidized structure with drawn size tolerance and lubricant carrier. CH: for self-tapping/self-drilling screws and small wear parts needing a 550–750 HV case over a tough boron-hardened core. Yield strength is 430 MPa in +AC+C versus 700 MPa in CH.
How much does 18B2 cost?
18B2 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 10083-3 — Steels for quenching and tempering: alloy steels — CEN (2006)
- ISO 898-1 — Mechanical properties of fasteners, property classes 8.8/9.8 — ISO (2013)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (boron steels, hardenability) — ASM International (1990)
- ASM Handbook Vol.14A — Metalworking: Bulk Forming (cold heading) — ASM International (2005)
- Cold-heading quality boron steel wire datasheets (+U, +AC, +C conditions) — European/Chinese wire rod producers (2023)
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.