Steel EN8 · supply condition
Steel EN8-CR
Properties of the CR condition, compared with the other EN8 tempers.
Choose for thin strip/sheet with good surface and closer thickness tolerance; strength raised, ductility reduced.
What is EN8-CR?
EN8-CR is EN8 supplied in the CR condition — choose for thin strip/sheet with good surface and closer thickness tolerance; strength raised, ductility reduced. EN8-CR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 58% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). EN8-CR 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). HR is the default condition FabDigit quotes; CR is available on request or by drawing note.
Advantages
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 88% of steel grades
- Easy to machine — 60/100, better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 82% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 83% of steel grades
EN8-CR properties
Typical room-temperature values for EN8-CR — 8 properties are specific to this condition; the rest are grade-level values shared by every EN8 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
EN8-CR 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
EN8-CR has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 58% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
EN8-CR is rated for continuous service to 400°C (752 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 88% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
EN8-CR conducts electricity at 10 % IACS, better than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of EN8-CR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
EN8-CR's machinability is good (60/100, better than 83% of steel grades); weldability fair (45/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other EN8 tempers and conditions
EN8 is also supplied in 5 other conditions. The full side-by-side table is on the EN8 overview.
- HRDefaultMost stocked form: hot-rolled black bar/plate for general machined parts that will be heat treated or used as-is.310 MPa yield · 179 HB
- Q&TChoose for loaded shafts, gears, keys and studs needing higher yield and fatigue strength; hardenable depth limited to roughly 30–60 mm diameter.620 MPa yield · 25 HRC
- CDBright, size-accurate bar for shafts and turned parts where no further heat treatment is planned; highest as-supplied yield of the unhardened conditions.540 MPa yield · 201 HB
- CRChoose for thin strip/sheet with good surface and closer thickness tolerance; strength raised, ductility reduced.470 MPa yield · 190 HB
- NormalizedUse for uniform fine-grained structure and predictable machining/strength in larger sections, typically before final machining or induction hardening.370 MPa yield · 185 HB
- AnnealedPick when maximum softness/ductility is needed for cold forming, deep machining or stress relief before hardening.300 MPa yield · 155 HB
Working with EN8-CR
Is EN8 easy to machine?
Machines readily in HR/normalized condition with carbide or HSS (≈60 % of AISI 1212); rough-machine before hardening and expect ~50 % rating and shorter tool life above 250 HB.
Can EN8 be welded?
Weldable with low-hydrogen electrodes but 0.4 % C demands 150–260 °C preheat, controlled interpass and post-weld stress relief/temper to avoid hard martensitic HAZ cracking.
Can EN8 be formed, bent or molded?
Hot forge 1050–1200 °C then normalize; cold bending is limited — use annealed stock and generous bend radii (>3 t).
What surface finishes work on EN8?
No anodizing; protect by zinc/nickel/hard-chrome plating, phosphating, black oxide, paint or oiling — bare bar rusts quickly in humid storage.
EN8 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 |
|---|---|---|
| CBS 970 080M40 / EN8 | 0.36 – 0.44 | 0.4 |
| Si | 0.1 – 0.4 | 0.25 |
| Mn | 0.6 – 1 | 0.8 |
| Smax; EN8M free-cutting version 0.20–0.30 S | ≤ 0.05 | 0.03 |
| P | ≤ 0.05 | 0.03 |
| Fe | balance | — |
EN8-CR — frequently asked
What is EN8-CR used for?
EN8-CR is typically used for crankshafts, shafts and industrial bolts. In short: workhorse English carbon bar.
What is the yield strength of EN8-CR?
EN8-CR has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 58% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is EN8-CR easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines readily in HR/normalized condition with carbide or HSS (≈60 % of AISI 1212); rough-machine before hardening and expect ~50 % rating and shorter tool life above 250 HB.
Can EN8-CR be welded?
With care — weldability is rated fair (45/100). Weldable with low-hydrogen electrodes but 0.4 % C demands 150–260 °C preheat, controlled interpass and post-weld stress relief/temper to avoid hard martensitic HAZ cracking.
What surface finishes work on EN8-CR?
No anodizing; protect by zinc/nickel/hard-chrome plating, phosphating, black oxide, paint or oiling — bare bar rusts quickly in humid storage.
Can EN8-CR be formed, bent or molded?
Hot forge 1050–1200 °C then normalize; cold bending is limited — use annealed stock and generous bend radii (>3 t).
What is the maximum service temperature of EN8-CR?
EN8-CR 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.
What is the difference between EN8-HR and EN8-CD?
HR is the default condition — most stocked form: hot-rolled black bar/plate for general machined parts that will be heat treated or used as-is. CD: bright, size-accurate bar for shafts and turned parts where no further heat treatment is planned; highest as-supplied yield of the unhardened conditions. Yield strength is 310 MPa in HR versus 540 MPa in CD.
Can FabDigit make parts in EN8-CR?
Yes — EN8-CR is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- BS 970 Part 1 / Part 3 — 080M40 (EN8) wrought steels — BSI (1991)
- GB/T 699 — Quality carbon structural steels (45 ) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carbon steel hardenability/tempering) — ASM International (1991)
- SAE J403 / ASTM A576 — AISI 1040/1045 carbon steel bars — SAE / ASTM (2017)
- Mysteel / 1688 — Mysteel (2025)
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.