Steel 35B2
EN 35B2
35B2 (1.5511) is a higher-carbon boron steel in the EN 10083/10250 alloy steel family, developed for fasteners and pins that need high strength after quenching and tempering.
Reference datasheet — 35B2 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 +QT condition
35B2 tempers and conditions
35B2 is supplied in 8 conditions, soft to hard. +QT 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 |
|---|---|---|---|---|---|---|
Annealed | Lowest-hardness machining condition (max ~197 HB) for pre-machined parts hardened afterwards. | 330 | 560 | 23 | 8 HRC | 8.2 % IACS |
Spheroidize annealed | Pick for cold-heading wire and cold-extruded blanks; globular carbide structure gives maximum cold upsetting ability before final Q&T. | 340 | 540 | 24 | 160 HB | — |
Normalized | Use to homogenize grain size after forging and before machining or hardening. | 370 | 620 | 20 | 9 HRC | 8 % IACS |
Hot rolled | Cheapest mill condition; buy when you will anneal, spheroidize or Q&T in-house. | 380 | 640 | 18 | 10 HRC | 8 % IACS |
Treated to specified hardness range | Ordered when a mill-guaranteed hardness band (typically 170–230 HB) is needed for automatic machining or cold forming. | 420 | 660 | 17 | 14 HRC | 8.2 % IACS |
Cold drawn | Choose for close tolerance, bright surface pins and shafts used without further heat treatment. | 600 | 720 | 9 | 17 HRC | 7.9 % IACS |
+QTDefault Quenched and tempered | Standard delivery/final condition for high-strength bolts, pins and shafts up to ~16 mm section. | 760 | 950 | 12 | 31 HRC | — |
+QT high strength | Select for property-class 10.9 fasteners and highly loaded pins in small sections; watch hydrogen embrittlement when plating. | 950 | 1,100 | 10 | 36 HRC | — |
What is 35B2?
35B2 (1.5511) is a higher-carbon boron steel in the EN 10083/10250 alloy steel family, developed for fasteners and pins that need high strength after quenching and tempering. It is supplied as annealed, spheroidized, normalized, cold-drawn or ready-heat-treated bar and wire (+A, +AC, +N, +C, +TH, +QT). In the default +QT condition it reaches about 760 MPa yield, 950 MPa tensile, 12 % elongation and 300 HB (31 HRC), with a maximum service temperature of 300 °C. Cold formability and weldability are the lowest in the boron series (CEV ≈ 0.5, formability score 20), and there is no corrosion resistance; use 28B2 or 23B2 where heading or welding dominates. 35B2 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). 35B2 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 85% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 35B2 used for?
- high-strength bolts
- fasteners
- structural pins
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
35B2 properties
Typical room-temperature values for 35B2-+QT; bars are the position among steel grades.
Physical3
35B2 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).
Mechanical16
35B2 has a yield strength of 760 MPa (110 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 85% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
35B2 is rated for continuous service to 300°C (572 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
35B2 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 35B2 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
35B2's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (30/100); formability poor (20/100).
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. 35B2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 35B2
Is 35B2 easy to machine?
Machine in +A/+AC/+TH (170–210 HB) with carbide at moderate feeds; in +QT above 300 HB expect ~50 % of 1212 rates and use coated carbide with rigid setups.
Can 35B2 be welded?
Weldable only with care in the annealed state (CEV ≈ 0.5): preheat 150–250 °C, low-hydrogen consumables and post-weld temper; avoid welding hardened fasteners.
Can 35B2 be formed, bent or molded?
Spheroidize-anneal (+AC) plus phosphate/soap or polymer lubricant for multi-station cold heading and thread rolling; hot forge 1100–1200 °C, finish above 900 °C, then normalize.
35B2 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 | 0.32 – 0.39 | 0.35 |
| Sisome mills to 0.40 max on wire rod | ≤ 0.3 | 0.2 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | |
| Slower S for cold-heading wire | ≤ 0.04 | |
| Crresidual | ≤ 0.3 | 0.1 |
| BTi or Al added to fix free nitrogen so boron stays effective | 8×10⁻⁴ – 0.01 | 0 |
| Fe | balance |
What surface finishes work on 35B2?
No corrosion resistance bare — zinc, zinc-nickel or zinc-flake coat, or phosphate plus oil; bake within 4 h after acid pickling/electroplating above ~1000 MPa to avoid hydrogen embrittlement.
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 35B2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5511
How much does 35B2 cost?
35B2 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
35B2 — frequently asked
What is 35B2 used for?
35B2 is typically used for high-strength bolts, fasteners and structural pins. In short: strongest boron fastener grade; limited cold formability; quench-and-temper only.
What is the yield strength of 35B2?
35B2 has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 35B2 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in +A/+AC/+TH (170–210 HB) with carbide at moderate feeds; in +QT above 300 HB expect ~50 % of 1212 rates and use coated carbide with rigid setups.
Can 35B2 be welded?
Not readily — weldability is rated poor (30/100). Weldable only with care in the annealed state (CEV ≈ 0.5): preheat 150–250 °C, low-hydrogen consumables and post-weld temper; avoid welding hardened fasteners.
What surface finishes work on 35B2?
No corrosion resistance bare — zinc, zinc-nickel or zinc-flake coat, or phosphate plus oil; bake within 4 h after acid pickling/electroplating above ~1000 MPa to avoid hydrogen embrittlement.
Can 35B2 be formed, bent or molded?
Spheroidize-anneal (+AC) plus phosphate/soap or polymer lubricant for multi-station cold heading and thread rolling; hot forge 1100–1200 °C, finish above 900 °C, then normalize.
What is the maximum service temperature of 35B2?
35B2 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 35B2 cost?
35B2 is a budget-cost steel ($), 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 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- EN 10263-4 Steel rod, bars and wire for cold heading — Steels for quenching and tempering — CEN (2018)
- EN 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)
- ASM Handbook Vol.4A — Steel Heat Treating Fundamentals and Processes — ASM International (2013)
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.