At Ananka Fasteners Pvt Ltd, we manufacture and supply fasteners certified to BS 4670. British Standard ‘Specification for alloy steel forgings’ (BS 4670:1971). Covers alloy steel forgings for general engineering, defined by the former ‘En’ series of alloy steels, supplied heat treated to specified mechanical property ranges. Used as forging/bar stock for machined and forged high-strength studs, bolts and heavy fasteners.
British Standard ‘Specification for alloy steel forgings’ (BS 4670:1971). Covers alloy steel forgings for general engineering, defined by the former ‘En’ series of alloy steels, supplied heat treated to specified mechanical property ranges. Used as forging/bar stock for machined and forged high-strength studs, bolts and heavy fasteners.
| Grade / Class | UNS / Designation | Type / Notes |
|---|---|---|
| En19 / 709M40-type | 42CrMo4-family | Cr-Mo through-hardening forging steel |
| En24 / 817M40-type | 36CrNiMo4/34CrNiMo6-family | Ni-Cr-Mo high-strength forging steel |
| En25 / 826M40-type | Ni-Cr-Mo | High-strength forging steel |
| En26 / 830M31-type | Ni-Cr-Mo | High-strength forging steel |
| En30B / 835M30-type | Ni-Cr-Mo | Very high strength forging steel |
Minimum mechanical requirements per BS 4670.
| Grade / Class / Condition | Tensile Strength, min | Yield Strength, min | Elongation, min % | Hardness |
|---|---|---|---|---|
| Cr-Mo (En19) Q&T | 125-145 (860-1000) | 100 (690) | 13 | 248-302 HB |
| Ni-Cr-Mo (En24) Q&T ‘T’ | 150-175 (1030-1200) | 125 (860) | 10 | 300-355 HB |
| Ni-Cr-Mo (En25) Q&T | 170-200 (1170-1380) | 140 (965) | 9 | 340-400 HB |
| Ni-Cr-Mo (En30B) Q&T | 200-230 (1380-1550) | 170 (1170) | 8 | 400-460 HB |
| Grade | Key Composition, % |
|---|---|
| En19 (Cr-Mo) | C 0.36-0.44, Cr 0.90-1.20, Mo 0.25-0.35 |
| En24 (Ni-Cr-Mo) | C 0.36-0.44, Ni 1.3-1.7, Cr 1.0-1.4, Mo 0.20-0.35 |
| En30B (Ni-Cr-Mo) | C 0.26-0.34, Ni 4.0-4.3, Cr 1.1-1.4, Mo 0.2-0.4 |
Alloy steel forgings analogous to BS 970 Part 1 En19/En24/En25/En30B, EN 10250-3, DIN 17200/EN 10083 42CrMo4 and 34CrNiMo6, ASTM A29/A711 forging stock.
For the official BSI standards catalogue, see the BSI standards listing. This external reference is provided for standards identification; the purchaser should verify the current edition applicable to the order.
We supply BS 4670 fasteners — bolts, screws, studs, nuts and washers as applicable — for energy, petrochemical, marine, structural and general engineering service, in a full range of sizes and finishes.
For technical documentation and quotations, buyers can also review the Ananka Fasteners manufacturing and supply range or contact the team through the fastener enquiry and technical support page.
Ananka Fasteners supplies every lot with full material traceability and third-party testing on request.
British Standard ‘Specification for alloy steel forgings’ (BS 4670:1971). Covers alloy steel forgings for general engineering, defined by the former ‘En’ series of alloy steels, supplied heat treated to specified mechanical property ranges. Used as forging/bar stock for machined and forged high-strength studs, bolts and heavy fasteners.
Ananka Fasteners supplies En19 / 709M40-type, En24 / 817M40-type, En25 / 826M40-type, En26 / 830M31-type, En30B / 835M30-type to BS 4670. See the Grades / Classes Covered table above for full details of each grade.
Minimum tensile strength, yield strength, elongation and hardness requirements vary by grade — see the Mechanical Properties table above for the complete breakdown.
We supply BS 4670 fasteners — bolts, screws, studs, nuts and washers as applicable — for energy, petrochemical, marine, structural and general engineering service, in a full range of sizes and finishes.
Yes. For a quotation, provide the required fastener type, grade, nominal size, dimensional standard, quantity and any inspection or certificate requirements.
Need a fastener released to BS 4670 for an industrial project? Send the required fastener type, grade, size, quantity and certification requirements to Ananka Fasteners. Our team can review the requirement and provide technical and commercial information for standard or custom configurations.
Recommended RFQ details: BS 4670 requirement, material grade, fastener type, nominal size, dimensional standard, quantity, inspection requirements and EN 10204 certificate requirements where applicable.
Data compiled per BS 4670 and industry references; provided for reference only — confirm against the current edition of the standard and certified mill test reports before design use.
