Fastener Part Standard - Machine Screw Nuts (Metric and Inch)
This SAE Part Standard covers selected machine screw nuts manufactured in accordance with American Society for Mechanical Engineers (ASME) dimensional standards. This document covers material most often used in ship systems and equipment but its use may be applied wherever nuts of the covered materials are used. This document permits the nuts to be identified and ordered by a part identification number (PIN) as defined in this document.
The purpose of this document is to assist the designer and other personnel in providing requirements and PINs for the most commonly used machine screw nuts. A PIN is normally required for all military applications and provides a useful means of communicating fastener requirements to suppliers and manufacturers in a very succinct manner.
While the materials, methods, applications and processes described or referenced in this standard may involve the use of hazardous materials, this standard does not address the hazards that may be involved in such use. It is the responsibility of manufacturers and users to consult with officials on the applicable health and environmental regulations regarding the handling, use and disposal of hazardous materials. For nuts, some of the hazardous materials concerns are the application of the materials in platings (coatings), release of toxic vapors due to heat (for example, welding) and environmental regulations for disposal.
The ASME removed machine screw nuts from ASME B18.6.3 and added them to ASME B18.2.2. That change is now reflected in SAE J2485.
Section 1: Added statement about potential hazardous materials.
Section 2: Added new reference standards.
Section 3: Added a Definitions paragraph.
Section 4: Added caution on Black Oxide Coatings. Added requirements on phosphate coatings and zinc/aluminum inorganic coatings.
Figure 1: Field 3 Configuration added Designator F for hex flange nut.
Field 5 Platings and Coatings added Designators K = Manganese Phosphate Coating, P = Zinc Phosphate Coating, X = Zinc/Aluminum Inorganic Coating-No Chromium Permitted and ZA = Zinc with clear topcoat (Hexavalent chromium prohibited). Z = Zinc Electroplate allows ZA to be furnished. Designator C for cadmium coating is inactivated for new design. Designator A for Aluminum plating is deleted due to misidentification of the coating. Hexavalent chrome is now prohibited due to environmental and regulatory concerns.
Table 1: Reformated to place Designators in alpha-numeric order. In accordance with industry practice, proof stress testing of machine screw nuts is no longer required.
Designator G steel expanded UNS compositions range to match standard production alloys.
Designators for CRES are reformatted. Designator S added alloy 302HQ and now identifies alloy XM7 as 18-9LW. New Designator S1 is added with 303 and 303Se free machining alloys. Designator S3 is added with 321 and 347 alloys. There is no change to current practice of allowing suppliers to choose the CRES alloy to be provided and this is noted. Hardness range of Designators in the S series is revised to align with ASTM F 594.
Designator C added copper alloys 260.
Designator C1 is added with naval brass alloys 462 and 464.
Designator T2 is added with titanium alloy 23, Ti-6Al-4V ELI.
Designator BN added “Grade 1” to alloy 686 and adjusted hardness and proof stress to match ASTM F 467.
Section 5: Informational notes revised and added.
Minor editorial changes, clarifications and corrections made throughout.
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