At Ananka Fasteners Pvt Ltd, we manufacture and supply fasteners certified to ASTM F959/F959M. Standard specification for compressible-washer-type direct tension indicators (DTIs/’squirter’ washers) for use with structural fasteners. Covers load-indicating washers with protrusions that flatten under load; requirements are the minimum bolt tension at the specified gap and coating/marking, not conventional tensile/yield. Inch (F959) for use with F3125 A325/A490 (and F1852/F2280); metric (F959M) for property class 8.8/10.9.
Standard specification for compressible-washer-type direct tension indicators (DTIs/’squirter’ washers) for use with structural fasteners. Covers load-indicating washers with protrusions that flatten under load; requirements are the minimum bolt tension at the specified gap and coating/marking, not conventional tensile/yield. Inch (F959) for use with F3125 A325/A490 (and F1852/F2280); metric (F959M) for property class 8.8/10.9.
| Grade / Class | UNS / Designation | Type / Notes |
|---|---|---|
| Type 325 / 8.8 | For A325 / class 8.8 assemblies | DTI matched to lower-strength high-strength bolts |
| Type 490 / 10.9 | For A490 / class 10.9 assemblies | DTI matched to higher-strength bolts |
Minimum mechanical requirements per ASTM F959/F959M.
| Grade / Class / Condition | Tensile Strength, min | Yield Strength, min | Elongation, min % | Hardness |
|---|---|---|---|---|
| Type 325 (with A325/8.8 bolt) | n/a (indicates min bolt tension at gap) | n/a | n/a | Hardened DTI; verify gap 0.005 in feeler refusal |
| Type 490 (with A490/10.9 bolt) | n/a (indicates min bolt tension at gap) | n/a | n/a | Hardened DTI; higher preload target |
| Grade | Key Composition, % |
|---|---|
| DTI washer | Heat-treated carbon/alloy steel washer with compressible protrusions; coating per order (plain, mechanically galvanized, etc.) |
Function equivalent to BS EN 14399-9 (HRD direct tension indicators). Used with ASTM F3125 (A325/A490) and F1852/F2280 assemblies.
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 F959/F959M 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 compressible-washer-type direct tension indicators (DTIs/’squirter’ washers) for use with structural fasteners. Covers load-indicating washers with protrusions that flatten under load; requirements are the minimum bolt tension at the specified gap and coating/marking, not conventional tensile/yield. Inch (F959) for use with F3125 A325/A490 (and F1852/F2280); metric (F959M) for property class 8.8/10.9.
Ananka Fasteners supplies Type 325 / 8.8, Type 490 / 10.9 to ASTM F959/F959M. 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 F959/F959M 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 F959/F959M 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 F959/F959M requirement, material grade, fastener type, nominal size, dimensional standard, quantity, inspection requirements and EN 10204 certificate requirements where applicable.
Data compiled per ASTM F959/F959M and industry references; provided for reference only — confirm against the current edition of the standard and certified mill test reports before design use.
