GMNA GM6171M PDF

This standard covers material and performance requirements for case hardened type TR (thread rolling tapping screws, in sizes 6 mm (1/4 in.) and smaller, suitable for use in general engineering applications. Where type TR screws in sizes 5 and 6 mm (No. 10 and ¼ in.) are to be used in structural type attachments and for all larger screw sizes, the induction hardened variety covered in GM6202M specification shall apply.

CAUTION: Case hardened fasteners may be subject to delayed brittle fracture caused by hydrogen resulting from corrosion. Small amounts of water such as might condense from humid air can cause this type of failure, particularly in the presence of anodic surface coating such as zinc or cadmium plate. Consequently, it is recommended that case hardened fasteners not be used in structural applications.

NOTE: This specification is intended to supersede the GM6010M specification for inch sizes of case hardened type TT tapping screws.

NOTE: The performance values specified in this standard are not valid for design unless all conditions of the application are identical to the combination of laboratory conditions described in the testing procedure.