H & S Plating Page

Plating

Electro-Zinc & Clear	Zinc is the most popular of all commercial platings because it is relatively economical and offers good corrosion resistance in environments not subject to excessive moisture. Commercial zinc plating has a standard minimum thickness of 0.00015 inches. A clear or bluish chromate finish is applied on top of the zinc. It is recommended by certain industry experts that case-hardened parts which are electro-plated should be baked after plating to minimize the risk of hydrogen embrittlement.
Electro-Zinc & Yellow	Commercial zinc-yellow plating has a standard minimum thickness of 0.00020 inches. Yellow chromate offers a greater degree of protection from white corrosion than does clear chromate.
Cadmium & Wax	Cadmium plating results in a smoother surface and greater resistance to white oxidation spots than zinc plating. However, cadmium is a much more toxic metal than zinc, which makes the plating process more difficult and costly. The standard most commercial platers use when applying cadmium is a minimum thickness of .0002 inches. A supplemental wax coating is often added as a lubricant when cadmium is used on prevailing torque lock nuts.
Hot-Dip Galvanized	Hot dip galvanizing is generally the most effective way to apply a sufficient thickness of zinc to threaded fasteners for the zinc to serve as a corrosion protectant in harsh environments. Bolts and nuts over 3/8 inches diameter, and all sizes if washers shall have a zinc coating with an average thickness of 0.0021 in. with no individual bolt having a coating of less than 0.0017 in.
Nickel	Nickel has more of a silver color to it than zinc and has similar corrosion resistant characteristics. It is the standard finish of cap nuts and countersunk finishing washers.
Black Phosphate & Oil	The most common standard coating of black phosphate and oil is 1100 mg. Per sq/ft. minimum. The oil serves as a rust inhibitor and a lubricant. Some fasteners with this plating are required to pass a salt-spray test, the duration and cost of which must be agreed upon between buyer and seller prior to the sale. Floorboard screws, frame bolts, Grade-GT locknuts and spring nuts are usually supplied with a black phosphate and oil finish.
Baking of Case Hardened Parts	Electroplated screws which are case hardened should be baked for a mini mum of 4 hours within the temperature range of 375-450 F no later than 4 hours after the plating operation. However, this process does not guarantee that hydrogen embrittlement will not still be present after baking or that it will not occur at a later date while in service. Specialized testing or a substitute part may be required, depending on the application. This heat treatment practice is recommended for tapping screws, drywall screws, SEMS screws, clinch nuts and clinch studs.
Passivation	A chemical process in which Stainless Steel products are cleansed of surface impurities. Provides a somewhat brighter appearance and may aid in reducing magnetism.
Anodize / Alodine	Chemical treatments used for aluminum parts. Aids in corrosion resistance and can provide variance in color.

Electro-Zinc & Clear Zinc is the most popular of all commercial platings because it is relatively economical and offers good corrosion resistance in environments not subject to excessive moisture. Commercial zinc plating has a standard minimum thickness of 0.00015 inches. A clear or bluish chromate finish is applied on top of the zinc. It is recommended by certain industry experts that case-hardened parts which are electro-plated should be baked after plating to minimize the risk of hydrogen embrittlement.

Electro-Zinc & Yellow Commercial zinc-yellow plating has a standard minimum thickness of 0.00020 inches. Yellow chromate offers a greater degree of protection from white corrosion than does clear chromate.

Cadmium & Wax Cadmium plating results in a smoother surface and greater resistance to white oxidation spots than zinc plating. However, cadmium is a much more toxic metal than zinc, which makes the plating process more difficult and costly. The standard most commercial platers use when applying cadmium is a minimum thickness of .0002 inches. A supplemental wax coating is often added as a lubricant when cadmium is used on prevailing torque lock nuts.

Hot-Dip Galvanized
Hot dip galvanizing is generally the most effective way to apply a sufficient thickness of zinc to threaded fasteners for the zinc to serve as a corrosion protectant in harsh environments. Bolts and nuts over 3/8 inches diameter, and all sizes if washers shall have a zinc coating with an average thickness of 0.0021 in. with no individual bolt having a coating of less than 0.0017 in.

Nickel Nickel has more of a silver color to it than zinc and has similar corrosion resistant characteristics. It is the standard finish of cap nuts and countersunk finishing washers.

Black Phosphate & Oil The most common standard coating of black phosphate and oil is 1100 mg. Per sq/ft. minimum. The oil serves as a rust inhibitor and a lubricant. Some fasteners with this plating are required to pass a salt-spray test, the duration and cost of which must be agreed upon between buyer and seller prior to the sale. Floorboard screws, frame bolts, Grade-GT locknuts and spring nuts are usually supplied with a black phosphate and oil finish.

Baking of Case Hardened Parts Electroplated screws which are case hardened should be baked for a mini mum of 4 hours within the temperature range of 375-450 F no later than 4 hours after the plating operation. However, this process does not guarantee that hydrogen embrittlement will not still be present after baking or that it will not occur at a later date while in service. Specialized testing or a substitute part may be required, depending on the application. This heat treatment practice is recommended for tapping screws, drywall screws, SEMS screws, clinch nuts and clinch studs.

Passivation A chemical process in which Stainless Steel products are cleansed of surface impurities. Provides a somewhat brighter appearance and may aid in reducing magnetism.

Anodize / Alodine Chemical treatments used for aluminum parts. Aids in corrosion resistance and can provide variance in color.