Steel 17B2 +U (Hot rolled)
Finish state
EN 17B2
Cheapest starting stock for re-heating, forging or subsequent annealing and drawing; not for direct heavy cold heading.
Values for the +U condition
Other 17B2 tempers and conditions
17B2 is listed in 5 conditions; see the grade overview at 17B2.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose when maximum cold-heading/upsetting ductility is needed before drawing or multi-station forming. | 265 | 430 | 28 | 120 HB | — |
+UThis page Hot rolled | Cheapest starting stock for re-heating, forging or subsequent annealing and drawing; not for direct heavy cold heading. | 320 | 490 | 22 | 145 HB | — |
+AC+CDefault Spheroidize annealed then cold drawn | Standard cold-heading wire condition: good size/surface control with enough residual ductility for bolt and screw heading. | 400 | 520 | 13 | 150 HB | — |
Cold drawn from untreated (hot rolled) stock | Economical drawn wire/bar for light cold forming, rivets and turned parts where full heading ductility is not required. | 470 | 580 | 10 | 170 HB | — |
Hardened and tempered | Final strength condition for headed fasteners after forming: boron gives full through-hardening in small diameters, then temper to 26–32 HRC. | 700 | 850 | 13 | 29 HRC | — |
What is 17B2 +U?
17B2 +U is 17B2 supplied in the +U condition — cheapest starting stock for re-heating, forging or subsequent annealing and drawing; not for direct heavy cold heading. 17B2 +U has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 81% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi). 17B2 +U has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F). +AC+C is the default condition FabDigit quotes; +U is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Forms and bends easily — 75/100, better than 90% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
Limitations
- Low strength — 320 MPa (46.4 ksi), worse than 81% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
17B2 +U properties
Typical room-temperature values for 17B2 +U; 15 are specific to this condition. Other listed values are 17B2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
17B2 +U has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F).
Mechanical14
17B2 +U has a yield strength of 320 MPa (46.4 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 81% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
17B2 +U is rated for continuous service to 300°C (572 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
17B2 +U 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 17B2 +U 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
17B2 +U's machinability is good (55/100, better than 62% of steel grades); weldability very good (70/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 17B2 +U
Is 17B2 easy to machine?
Soft and somewhat gummy in +AC/+AC+C — use sharp positive-rake tools, high speed and good coolant; machine before hardening or expect ~50 % of soft-state tool life at 29 HRC.
Can 17B2 be welded?
Low carbon equivalent welds readily by MIG/spot/projection, but boron sharply raises HAZ hardenability — keep heat input moderate, avoid welding parts already quenched, and stress-relieve/temper critical joints.
Can 17B2 be formed, bent or molded?
Designed for multi-station cold heading, upsetting and thread rolling in the spheroidize-annealed and drawn condition; use phosphate+lube or polymer carrier and keep drawing reductions per pass modest to preserve heading ductility.
What surface finishes work on 17B2?
No inherent corrosion protection: zinc electroplating (with baking to avoid hydrogen embrittlement above 1000 MPa), hot-dip galvanizing, zinc-flake (Dacromet/Geomet) or phosphate-and-oil are standard; polishes and plates well after pickling.
17B2 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 |
|---|---|---|
| Cgrade designator 17 = 0.17 % C nominal | 0.15 – 0.2 | 0.17 |
| Silow Si for cold formability | ≤ 0.3 | 0.15 |
| Mn | 0.5 – 0.9 | 0.7 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Crresidual | ≤ 0.3 | 0.1 |
| Bhardenability agent; requires Ti/Al for free-N control | 8×10⁻⁴ – 0.01 | 0 |
| Tinitrogen fixing so boron stays in solution | ≤ 0.05 | 0.03 |
| Aldeoxidation / N control | 0.02 – 0.06 | 0.04 |
| Fe | balance | — |
17B2 +U — frequently asked
What is 17B2 +U used for?
17B2 +U is typically used for bolts, fasteners and cold-formed parts. In short: higher carbon than 15B2; cold-heading fastener steel; boron-boosted hardenability.
What is the yield strength of 17B2 +U?
17B2 +U has a typical yield strength of 320 MPa (46.4 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 81% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 17B2 +U easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Soft and somewhat gummy in +AC/+AC+C — use sharp positive-rake tools, high speed and good coolant; machine before hardening or expect ~50 % of soft-state tool life at 29 HRC.
Can 17B2 +U be welded?
Yes — weldability is rated very good (70/100). Low carbon equivalent welds readily by MIG/spot/projection, but boron sharply raises HAZ hardenability — keep heat input moderate, avoid welding parts already quenched, and stress-relieve/temper critical joints.
What surface finishes work on 17B2 +U?
No inherent corrosion protection: zinc electroplating (with baking to avoid hydrogen embrittlement above 1000 MPa), hot-dip galvanizing, zinc-flake (Dacromet/Geomet) or phosphate-and-oil are standard; polishes and plates well after pickling.
Can 17B2 +U be formed, bent or molded?
Designed for multi-station cold heading, upsetting and thread rolling in the spheroidize-annealed and drawn condition; use phosphate+lube or polymer carrier and keep drawing reductions per pass modest to preserve heading ductility.
What is the maximum service temperature of 17B2 +U?
17B2 +U 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.
Sources
- EN 10263-4 Steel rod, bars and wire for cold heading and cold extrusion — Part 4: Steels for quenching and tempering — CEN (2019)
- EN 10083-3 Steels for quenching and tempering — Alloy steels — CEN (2006)
- EN 10027-2 Designation systems for steels — Numeric system (material number 1.5502) — CEN (2015)
- ISO 898-1 Mechanical properties of fasteners — Bolts, screws and studs (property class 8.8) — ISO (2013)
- 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)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.