At Ananka Fasteners Pvt Ltd, we manufacture and supply fasteners certified to ASTM A540/A540M. Standard specification for alloy-steel bolting for special applications (including nuclear and high-integrity service). Grades B21/B22/B23/B24 supplied in strength classes 1-5; higher classes give higher strength at reduced ductility.
Standard specification for alloy-steel bolting for special applications (including nuclear and high-integrity service). Grades B21/B22/B23/B24 supplied in strength classes 1-5; higher classes give higher strength at reduced ductility.
| Grade / Class | UNS / Designation | Type / Notes |
|---|---|---|
| B21 | K13502 | Cr-Mo-V (similar to 4142 mod) |
| B22 | K14073 | Cr-Mo-V |
| B23 | G43400 | Ni-Cr-Mo (4340-type) |
| B24 | K24064 | Ni-Cr-Mo (4340-type, higher hardenability) |
| B24V | – | Ni-Cr-Mo-V variant |
Minimum mechanical requirements per ASTM A540/A540M.
| Grade / Class / Condition | Tensile Strength, min | Yield Strength, min | Elongation, min % | Hardness |
|---|---|---|---|---|
| Class 1 | 165 ksi (1140 MPa) | 150 ksi (1035 MPa) | 10 | 321-444 HBW |
| Class 2 | 155 ksi (1070 MPa) | 140 ksi (965 MPa) | 11 | 311-415 HBW |
| Class 3 | 145 ksi (1000 MPa) | 130 ksi (895 MPa) | 12 | 293-388 HBW |
| Class 4 | 135 ksi (930 MPa) | 120 ksi (825 MPa) | 13 | 269-363 HBW |
| Class 5 | 115-120 ksi (795-825 MPa) | 100-105 ksi (690-725 MPa) | 15 | 248-321 HBW |
| Grade | Key Composition, % |
|---|---|
| B21 | Cr 0.85-1.15, Mo 0.30-0.40, V 0.20-0.30, C 0.36-0.44 |
| B22 | Cr 0.75-1.00, Mo 0.50-0.65, V 0.25-0.35, C 0.36-0.44 |
| B23 | Ni 1.55-2.00, Cr 0.65-0.95, Mo 0.20-0.30, C 0.37-0.44 |
| B24 | Ni 1.65-2.00, Cr 0.70-0.95, Mo 0.30-0.40, C 0.37-0.44 |
ASME SA-540; B23/B24 chemistries are AISI 4340-family; used where A193 B7/B16 strength is insufficient (higher classes) and for nuclear ASME III bolting.
For the official ASTM International standards catalogue, see the ASTM International standards listing. This external reference is provided for standards identification; the purchaser should verify the current edition applicable to the order.
We supply ASTM A540/A540M 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.
Standard specification for alloy-steel bolting for special applications (including nuclear and high-integrity service). Grades B21/B22/B23/B24 supplied in strength classes 1-5; higher classes give higher strength at reduced ductility.
Ananka Fasteners supplies B21, B22, B23, B24, B24V to ASTM A540/A540M. 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 ASTM A540/A540M 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 ASTM A540/A540M 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: ASTM A540/A540M requirement, material grade, fastener type, nominal size, dimensional standard, quantity, inspection requirements and EN 10204 certificate requirements where applicable.
Data compiled per ASTM A540/A540M and industry references; provided for reference only — confirm against the current edition of the standard and certified mill test reports before design use.
