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Engineering Steel Bar — Black Round Bar

Black Round Bar.
Up to 600mm Diameter.

Hot-rolled black round bar in 20+ engineering steel grades — from 16mm to 600mm diameter. Mill scale surface finish. Cost-effective for large-diameter billets, structural applications and heavy engineering. Cut to any length from one piece.

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Symmetrical aisle between walls of orange cantilever racking loaded with large diameter black round bar
Large diameter black round bar ends with chalk grade markings — S355 400mm diameter black bar
Operative in full PPE loading 400mm EN3B black round bar onto Combilift using chain remote
EN3B 400mm black round bar on Combilift forks — blue/red colour-coded end, orange racking behind
22mm–600mmDiameter range
BS EN 10060Dimensional std
1 pieceMinimum order
2–3 daysCut-to-length
About This Profile

What is Black Round Bar?

Black bar (hot-rolled bar) is produced by rolling steel at high temperature and allowing it to cool with the characteristic dark mill scale surface intact. It is dimensionally less precise than bright bar but significantly more economical for larger diameters where cold drawing is impractical.

Parkside Steel holds one of the widest single-site ranges of large-diameter black round bar in the UK — up to 600mm diameter in selected alloy grades. Our band saws cut up to 600mm diameter. The size range makes us the natural choice for oil and gas, defence and heavy engineering buyers who need large-section alloy bar with 3.1 material test certificates.

Tolerances

Dimensional Standards.

Hot rolled: Rolled at high temperature, left with dark mill scale surface. Less precise than bright bar — tolerances per BS EN 10060 (approx. ±0.5–2% of diameter depending on size). Surface must typically be turned before use in precision components.

Full tolerance tables by diameter: BS EN 10278 reference ›

Size Range

Available Sizes.

Stocked in both metric and imperial sizes. Cut to any length from 1 piece. −0/+2mm standard cut tolerance.

GradeBS / EN DesignationSize RangeConditionStandard
EN8080M4025–600mmHot rolled blackBS EN 10060
EN3B070M2025–600mmHot rolled blackBS EN 10060
EN1A230M07100–220mmHot rolled blackBS EN 10060
S355 J2S355J225–400mmHot rolled blackBS EN 10025
EN9070M5525–300mmHot rolled blackBS EN 10060
EN1942CrMo4 / 708M4025–500mmHot rolled blackBS EN 10060
EN24T817M40T25–500mmHot rolled black (Q+T)BS EN 10060
EN36B655M1360–300mmHot rolled blackBS EN 10060
EN36C832M1360–300mmHot rolled blackBS EN 10060
EN40B722M2422–300mmHot rolled black (Q+T)BS EN 10060
8620805M20 / SAE 862040–200mmHot rolled blackBS EN 10060
Applications

Typical Applications.

  • ✓Large-diameter billets machined from solid
  • ✓Oil and gas drill collar and tool joint stock (EN24T)
  • ✓Structural and load-bearing applications (S355)
  • ✓Agricultural axles and heavy hubs
  • ✓Heavy plant shafts and pivot pins
  • ✓Forging blanks and ring-rolled pre-forms
Related Technical Guides

Go Deeper.

Grade Equivalents► Bright Bar Tolerances► Weight Calculator►
Steel Grades Available in Black Round Bar

Choose Your Grade.

All grades listed below are available in black round bar. Click any grade for full data sheet, chemical composition and mechanical properties.

EN8080M40Medium carbon — general shafts, keysEN1942CrMo4Cr-Mo alloy — high-tensile shaftsEN24T817M40T / 4340Ni-Cr-Mo Q+T pre-treatedEN1A230M07Free-cutting — automatic turningEN3B070M20Mild steel — weldable fabricationEN9070M55High carbon — wear, springsEN40B722M24Nitriding — hydraulic rodsEN36655M13Case hardening — gears8620805M20Automotive case hardeningS355S355J2Structural — fabricationEN36C832M13Case hardening — heavy-duty gears

Ready to Order Black Round Bar?

Tell us your grade, size and quantity. We confirm stock, price and delivery date on the same call.

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