1. Scope

This specification covers the chemical, and mechanical requirement for Structural Bolting Assemblies -Bolts. Nuts and Washers, in inch and metric dimensions, 1/2" through 1-1/2", and M12 through M36 made from Strain Hardened Stainless Steel, Duplex Stainless Steel, or Precipitation Hardening Stainless Steel. For use in Stainless Steel Structures where high strength bolting assembly performance is specified. The dimensional requirements are similar to standard high strength structural bolting assemblies covered in ASTM F3125/F325M and ASME B18.2.6.

Keywords

Rotational Capacity Test; Slip Critical Connections

Rationale

1. The European fastener market enjoys the use high-strength austenitic stainless steel materials that are beyond those offered by any ASTM standards.
2. We propose to bring these materials into an existing ASTM F16 Fastener Standard, or develop a new standard.
3. One approach is to add them to F593 and F594 (hex cap and heavy hex cap screws and studs) and for smaller sizes, to F837, F879 and F880 (socket products)
4. Another approach, and likely the best choice, is to develop new standards that mirror the existing standards.
5. The goal is to offer stainless steel bolting materials /systems that can offer the same performance as ASTM F3125/F3125M materials, and possibly beyond that.
6. ASTM A1082 offers duplex stainless steel alloys with tensile/yield levels at 800/550 MPa, ( 110/80 ksi)
7. ISO 3506-1 offers Grade D8 High molybdenum super-austenitic alloy, and grades A4/A5/A8 austenitic alloys with a tensile/yield of 1000/800 MPa.
8. The super-duplex materials under consideration have tensile/yield levels of 1000/900 MPa (145/130 ksi) and 1200/1080 (174/156 ksi).
9. These new alloys, when covered by ASTM standards, will be made more available to North American Fastener Manufacturers and fasteners made from them will be more attractive and available to users.
10. For F593 and F594, or for the new standard, a new Alloy Group – Group 8 will be added and the grades designated using the remaining unused letters – Q, Y, or Z. Probably the same for the socket product standards.
11. Nut performance will be critical to the function of the bolting system.
12. Hard stainless steel flat washers will be critical to the function of the bolting system. Toby Anderson is working on a new ASTM standard for Stainless Steel Flat Washers.
13. Designated lubrication or coatings to control friction and prevent galling will be critical to the function of the bolting system.
14. Some of the higher strength and larger sizes may not be practical for headed bolting, therefore systems with studs and nuts may be designated.
15. The descriptions of conditions will probably be adequate for these alloys, but may need some additional wording, or possibly new conditions added.

The title and scope are in draft form and are under development within this ASTM Committee.