GMNA GM337M PDF

Thisspecification specifies the mechanical properties and material requirements for cold formed and headed non-heat treated externally threaded fasteners in nominal thread diameters < M12. In addition, this specification specifies other requirements which are included in GM500M. These additional requirementsare included in subsequent sections of this specification. This specification includes only 8C and 9C grades which are equivalent to property classes 8.8 and 9.8 respectively in GM500M. Age hardening is allowed up to 600C maximum to meet minimum mechanical requirements if necessary.

Material Description. Figure 1 specifies steels for different property classes of fasterners covered by this standard.

Material Identification.

Designation System. Property grades are designated by numbers where increasing numbers represent increasing tensile strengths. The designation sysmbol consists of two parts. The number approximates 1/100 of the minumum tensile strength in MPa. The letter C indicates a non-heat treated product.

Bolts and Screws. Fasteners manufactured to this standard, except internal drive head screws, shall be marked (8C or 9C) permanently and clearly to identify the proeprty grade and fastener manufacturer. Making shall be located on the top of the head and may be raised or recessed unless otherwise ordered by the purchaser. When raised, markings shall project not less than 0.1 mm above the surface of the head, and height thereof shall conform to the requirements of GM500M.

Studs. Shall be permanently and clearly marked with either 8C or 9C to identify the proeprty grade. Markings shall be located on the extreme end of the stud, shall be as large as manufacturing permits and may be raised or depressed at the option of the manufacturer.

Cross-Reference of Replaced Specifications.

Subparagraphs were not applicable.

Symbol. Not applicable.

Typical Application. This standard is applicable to bolts, screws and studs. This standard does not cover set screws and similar threaded fasterners. Fasteners included in this specification can be used as a sems screw if required.

Remarks. Not Applicable.