Introduction to GB/T 5267.1-2002 [Fasteners — Electroplated Coatings]

This standard specifies the dimensional requirements and coating thicknesses for electroplated coatings on steel and steel alloy fasteners, and provides recommendations for hydrogen embrittlement relief of high tensile strength, hardened, or surface-hardened fasteners.

This standard applies to electroplated coatings for threaded fasteners and other fasteners. It is also generally applicable to fasteners capable of cutting or forming matching internal threads, such as self-tapping screws, wood screws, self-drilling tapping screws, and thread-forming screws. The provisions of this standard also apply to non-threaded fasteners such as washers and pins.

Compared with GB/T 5267-1985, the main changes include:

Adjustments to terminology and definitions;

Removal of service condition classifications for electroplated coatings;

Addition of coating thickness upper deviation requirements for thread pitches P = 0.2–0.3 mm, and adjustments to some other thread pitch requirements;

Removal of old acceptance inspection requirements for coating thickness and adoption of GB/T 90.1 requirements;

Revision and supplementation of hydrogen embrittlement relief information;

Removal of local thickness measurement methods;

Addition of coding and marking systems for electroplated threaded parts;

Revision of guidance procedures for accommodating metallic coating thickness;

Addition of coating marking examples.

Appendices D “Measurement Method for Batch Average Coating Thickness” and E “Type A Coding System for Electroplated Threaded Parts” are normative appendices.

Appendices A “Hydrogen Embrittlement Relief Measures,” B “Corrosion Resistance of Metallic Coatings in Salt Spray Tests,” C “Guidance Procedure for Accommodating Metallic Coating Thickness,” F “Examples of Coating Markings,” and G “Surface Areas of Screws and Nuts” are informative appendices.

This standard specifies the dimensional requirements and coating thicknesses for electroplated coatings on steel and steel alloy fasteners, and provides recommendations for hydrogen embrittlement relief of high tensile strength, hardened, or surface-hardened fasteners.

This standard applies to electroplated coatings for threaded fasteners and other fasteners. It is also generally applicable to fasteners capable of cutting or forming matching internal threads, such as self-tapping screws, wood screws, self-drilling tapping screws, and thread-forming screws. The provisions of this standard also apply to non-threaded fasteners such as washers and pins.

Compared with GB/T 5267-1985, the main changes include:

Adjustments to terminology and definitions;

Removal of service condition classifications for electroplated coatings;

Addition of coating thickness upper deviation requirements for thread pitches P = 0.2–0.3 mm, and adjustments to some other thread pitch requirements;

Removal of old acceptance inspection requirements for coating thickness and adoption of GB/T 90.1 requirements;

Revision and supplementation of hydrogen embrittlement relief information;

Removal of local thickness measurement methods;

Addition of coding and marking systems for electroplated threaded parts;

Revision of guidance procedures for accommodating metallic coating thickness;

Addition of coating marking examples.

Appendices D “Measurement Method for Batch Average Coating Thickness” and E “Type A Coding System for Electroplated Threaded Parts” are normative appendices.

Appendices A “Hydrogen Embrittlement Relief Measures,” B “Corrosion Resistance of Metallic Coatings in Salt Spray Tests,” C “Guidance Procedure for Accommodating Metallic Coating Thickness,” F “Examples of Coating Markings,” and G “Surface Areas of Screws and Nuts” are informative appendices.