Steel C35EC +U (Hot rolled)
Finish state
EN 1.1172
Cheapest mill condition for rod that will be annealed or drawn by the fastener maker.
Values for the +U condition
Other C35EC tempers and conditions
C35EC is listed in 10 conditions; see the grade overview at C35EC.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Use when moderate softening and machining stock are enough and full spheroidizing is not needed. | 300 | 540 | 24 | 155 HB | 10.9 % IACS |
+ACDefault Spheroidize annealed | Default stock condition for cold heading/extrusion — maximum ductility, Rm limited to 550 MPa. | 310 | 500 | 25 | 145 HB | — |
Normalized | Uniform fine grain and predictable machining/heat-treat response for forged or hot-formed parts. | 330 | 580 | 20 | 165 HB | 10.8 % IACS |
+UThis page Hot rolled | Cheapest mill condition for rod that will be annealed or drawn by the fastener maker. | 340 | 600 | 20 | 170 HB | 10.8 % IACS |
Peeled / turned and polished bar | Decarb-free bright bar for direct machining of shafts and pins. | 340 | 590 | 20 | 170 HB | 10.8 % IACS |
Light-drawn | Small reduction for size/straightness and clean surface while keeping most cold-heading ductility. | 420 | 555 | 16 | 165 HB | 10.8 % IACS |
Hardened and tempered | Pick when the finished cold-formed part must reach ~700–800 MPa; hardenability band is guaranteed for consistent quench response. | 480 | 700 | 19 | 18 HRC | — |
Quenched & tempered core with induction/flame hardened surface | For wear surfaces on pins, shafts and cams: hard martensitic case (~50–55 HRC) over a tough tempered core. | 480 | 700 | 16 | 52 HRC | 9.5 % IACS |
Spheroidize annealed then cold drawn | Standard drawn cold-heading wire: sized and lubricant-coated, still formable enough for bolt heading. | 500 | 610 | 12 | 180 HB | — |
Cold drawn | Higher strength and good surface/tolerance for machined pins and shafts, limited further cold forming. | 590 | 700 | 9 | 205 HB | — |
What is C35EC +U?
C35EC +U is C35EC supplied in the +U condition — cheapest mill condition for rod that will be annealed or drawn by the fastener maker. C35EC +U has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 76% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi). C35EC +U 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). +AC is the default condition FabDigit quotes; +U is available on request or by drawing note.
Advantages
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
Limitations
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 86% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
C35EC +U properties
Typical room-temperature values for C35EC +U; 22 are specific to this condition. Other listed values are C35EC reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
C35EC +U 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).
Mechanical16
C35EC +U has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 76% of steel grades. Elongation at break is 20% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
C35EC +U is rated for continuous service to 400°C (752 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.1 µm/m·K (6.17 µin/in·°F).
Electrical3
C35EC +U conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of C35EC +U takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
C35EC +U's machinability is good (58/100, better than 75% of steel grades); weldability good (55/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C35EC +U
Is C35EC easy to machine?
Machines like 1035: spheroidized +AC is gummy and needs sharp positive-rake tools and good chip control; cold-drawn or normalized condition (170–210 HB) gives the best finish, ~55–70 % of 1212.
Can C35EC be welded?
Weldable with preheat 100–200 °C and low-hydrogen consumables (CE ≈ 0.45–0.50); post-weld stress relief or tempering advised on hardened parts to avoid cold cracking.
Can C35EC be formed, bent or molded?
Excellent cold heading, extrusion and thread rolling in +AC/+AC+C with phosphate-soap or polymer lubricant; hot forge 1100–1200 °C, harden 840–870 °C water/oil quench, temper 550–660 °C.
What surface finishes work on C35EC?
No corrosion resistance bare — specify zinc or zinc-nickel plating, phosphate + oil, or Dacromet/paint; bake at 190–220 °C after plating of hardened parts to prevent hydrogen embrittlement.
C35EC 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 |
|---|---|---|
| CEN 10263-4 | 0.32 – 0.39 | 0.35 |
| Silow Si for cold formability | ≤ 0.3 | 0.2 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.03 | 0.02 |
| Smax; low S for heading | ≤ 0.03 | 0.01 |
| Crresidual | ≤ 0.4 | 0.1 |
| Niresidual | ≤ 0.4 | 0.08 |
| Moresidual | ≤ 0.1 | 0.02 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance | — |
C35EC +U — frequently asked
What is C35EC +U used for?
C35EC +U is typically used for cold-headed fasteners, shafts, pins and small forgings. In short: cold-heading quality C35; controlled hardenability grade; best formability at 0.35 % C.
What is the yield strength of C35EC +U?
C35EC +U has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 600 MPa (87 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is C35EC +U easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like 1035: spheroidized +AC is gummy and needs sharp positive-rake tools and good chip control; cold-drawn or normalized condition (170–210 HB) gives the best finish, ~55–70 % of 1212.
Can C35EC +U be welded?
Yes — weldability is rated good (55/100). Weldable with preheat 100–200 °C and low-hydrogen consumables (CE ≈ 0.45–0.50); post-weld stress relief or tempering advised on hardened parts to avoid cold cracking.
What surface finishes work on C35EC +U?
No corrosion resistance bare — specify zinc or zinc-nickel plating, phosphate + oil, or Dacromet/paint; bake at 190–220 °C after plating of hardened parts to prevent hydrogen embrittlement.
Can C35EC +U be formed, bent or molded?
Excellent cold heading, extrusion and thread rolling in +AC/+AC+C with phosphate-soap or polymer lubricant; hot forge 1100–1200 °C, harden 840–870 °C water/oil quench, temper 550–660 °C.
What is the maximum service temperature of C35EC +U?
C35EC +U is rated for continuous use to about 400°C (752 °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 — steels for quenching and tempering — CEN (2018)
- EN 10263-2 Delivery conditions for steels not intended for heat treatment — CEN (2018)
- EN 10083-2 Steels for quenching and tempering — non-alloy steels (C35E/C35R) — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, machinability ratings — Industrial Press (2020)
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.