Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
EN 10278 (Cold-Drawn Bright Steel Bars) (21CrMoV5-7 / EN 10269 / 1.7709)
EN 10278 specifies dimensional tolerances, geometric tolerances and surface finish for cold-drawn bright steel bars. The standard is the companion to EN 10269 for 21CrMoV5-7 (Werkstoff 1.7709) round bar supplied in the cold-drawn finish for direct-machine fastener stock.
Request a Quote on EN 10278 (Cold-Drawn Bright Steel Bars) Bolting Stock and Fasteners
Scope
EN 10278 defines two tolerance classes for cold-drawn bright steel bars: h9 (closer) and h10 (standard) on diameter, with corresponding straightness, ovality and surface finish requirements. The standard applies to round, square, hexagonal and flat bar product forms; for 21CrMoV5-7 fastener stock the round product form is the relevant scope.
Dimensional Tolerance Classes
| Class | Tolerance on OD (50 mm bar) | Typical use |
|---|---|---|
| h9 (closer) | 0 to -62 micrometres | Direct-machine fastener stock without skin removal |
| h10 (standard) | 0 to -100 micrometres | General machining stock |
| h11 (peeled-and-polished) | 0 to -160 micrometres | Forging blanks; rough machining stock |
Surface Finish
Cold-drawn bright surface roughness Ra typically 1.6 to 3.2 micrometres. Drawing scratches, draw marks, and minor surface oxide are within specification. Defects exceeding the EN 10278 limit are cause for rejection.
Application to 21CrMoV5-7
For 21CrMoV5-7 (Werkstoff 1.7709) supplied in cold-drawn bright finish, EN 10278 h9 or h10 tolerance is supplied as standard on round bar OD 16 to 100 mm. Hot-rolled black bar (OD 50 to 300 mm) is supplied to EN 10060 / DIN 1013 dimensional tolerance and is governed by EN 10269 only.
Relationship to EN 10269
EN 10269 governs the chemistry, heat-treatment and mechanical-property requirements; EN 10278 governs the dimensional tolerance on cold-drawn bar. For 21CrMoV5-7 cold-drawn bright bar, both standards apply concurrently with the EN 10204 type 3.1 mill test certificate documenting compliance to both.
Frequently Asked Questions
Q. What is the difference between EN 10278 and EN 10060?
EN 10278 applies to cold-drawn bright bars (OD 16 to 100 mm typical) with tighter h9/h10 tolerance. EN 10060 applies to hot-rolled round bars (OD 50 to 300 mm) with looser as-rolled tolerance. For 21CrMoV5-7, the choice depends on the fastener machining route.
Q. Does EN 10278 govern surface finish?
Yes. EN 10278 specifies surface roughness Ra and acceptable surface defects. Cold-drawn bright bar Ra is typically 1.6 to 3.2 micrometres. Defects exceeding the standard limit are cause for rejection.
Q. Can I get 21CrMoV5-7 bar to EN 10278 h9 tolerance?
Yes. EN 10278 h9 (closer) tolerance is supplied as standard on cold-drawn bright bar OD 16 to 100 mm. Peeled-and-polished h11 on call-out for larger diameters.
Q. Is EN 10278 referenced in EN 10269?
EN 10269 references the dimensional-tolerance standards EN 10060 (hot-rolled) and EN 10278 (cold-drawn) as the applicable companions for the round-bar form. The EN 10204 type 3.1 certificate documents both chemistry compliance to EN 10269 and dimensional compliance to EN 10278 / EN 10060.
Related Standards and Properties
Related standards: EN 10269 · VdTUV Wb 350 · ASTM A193 · EN 10269 Equivalents. Properties pages: Chemistry · Mechanicals · Heat Treatment · Hardness · Creep-Rupture. Back to the 21CrMoV5-7 Alloy Hub.
Satisfaction Survey
