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Materials and Coatings Available for Fasteners

Updated 2/14/2017

Simpson Strong-Tie connectors, anchors and fasteners feature a wide range of materials and coatings designed to meet specific performance criteria. It is important to select a material and/or coating that is suitable for the intended application and environment based upon factors such as corrosion resistance and mechanical properties of the material. For more information on selecting connectors, anchors and fasteners based upon corrosion resistance, please see General Corrosion Risks, Guidelines for Selecting the Proper Materials and Coatings, Materials and Coatings Available – Connectors, and Materials and Coatings Available – Fasteners for more information on selecting products based on corrosion resistance.

Simpson Strong-Tie Company Inc. welcomes the opportunity to provide assistance in fastener selection; please call (800) 999-5099 or visit Ask Simpson online in the event that technical support is needed.

Low Level of Corrosion Resistance

Clear Zinc

Electroplated clear zinc is applied in accordance with ASTM F1941. In the ASTM B117 salt spray test, clear zinc provides 12 to 24 hours of corrosion protection before the first appearance of red rust depending on coating thickness.

Electrocoating (E-Coat™)

Electrocoat utilizes electrical current to deposit the coating material onto the fastener. After application, the coating is oven cured. Electrocoat is intended for dry, low corrosion applications.

Gray Phosphate

Gray phosphate provides a minimum level of corrosion resistance and is intended for dry, low corrosion applications.

Black Phosphate

Black phosphate provides a minimum level of corrosion resistance and is intended for dry, low corrosion applications.

Yellow Zinc

Electroplated zinc applied in accordance with ASTM F1941. In the ASTM B117 salt spray test, yellow zinc provides at least 24 hours of corrosion protection before the first appearance of red rust.

Class 1 Zinc Electroplate

Electroplated zinc applied in accordance with ASTM A641, Class 1. This is an electroplated zinc coating that provides a low level of corrosion resistance. The Class 1 coating has no specified red rust performance criteria in the B117 salt spray test.

Type 410 Stainless Steel

Type 410 stainless steel is a low-carbon martensitic grade of stainless steel that can be hardened and is inherently magnetic. This material provides corrosion resistance in mild atmospheres and many mild chemical environments.
See Passivation of Stainless-Steel Fasteners below.*

Coated Zinc

This coating system consists of an electroplated zinc base layer with an E-Coat top coat. It provides corrosion resistance that is adequate for low corrosion environments. In ASTM B117 salt spray testing at 500 hours of exposure, fasteners with this coating have an average red rust of less than 5%.

Medium Level of Corrosion Resistance

Quik Guard® Coating

Quik Guard is a proprietary coating that consists of an electroplated zinc base layer and a system of organic top coats. It provides corrosion resistance equivalent to hot-dip galvanization (ASTM A153, Class D) in some exposures. In ASTM B117 salt spray testing at 1,000 hours of exposure, fasteners with the Quik Guard coating have average red rust less than 2%.

Double-Barrier Coating

The Simpson Strong-Tie Double Barrier coating is a proprietary coating that provides a level of corrosion resistance that is equivalent to hot-dip galvanization (ASTM A153, Class D) in most non-marine environments.

Class D Hot-Dip Galvanized, ASTM A153

The Class D hot-dip galvanization is a coating that meets the requirements of ASTM A153, Class D, which is a minimum average of 1.0 oz/ft2 [305 g/m2] of zinc applied by a hot-dip process. Hot-dip galvanized fasteners are compliant with the 2012 and 2015 IBC and IRC.

Class 55 Mechanically Galvanized, ASTM B695

This is a mechanically-applied zinc coating that meets the requirements of ASTM B695, Class 55, which is a minimum average thickness of 55 microns with a supplementary overcoat. Screws with a Class 55 coating meet the requirements for use in preservative-treated and fire-retardant-treated wood as stated in the 2012 and 2015 IRC.

N2000® Mechanically Galvanized

This is a mechanically-applied proprietary zinc coating with a supplementary overcoat. In the ASTM B117 salt spray test at 1000 hours of exposure, fasteners with the N2000 coating exhibit average red rust less than 15%.

C-3 Mechanically Galvanized

A mechanically-applied coating that is zinc with a minimum of 20% tin in accordance with Australian Standard AS3566.2. In the ASTM B117 salt spray test at 1,000 hours of exposure, fasteners with the C3 coating exhibit average red rust of less than 2%.

High Level of Corrosion Resistance

Types 304 and 305 Stainless Steel

Types 304 and 305 stainless steels are nickel-chromium austenitic grades of stainless steel. Types 304 and 305 stainless steels are not hardened by heat treatment and are inherently nonmagnetic.

They provide very good corrosion resistance and are suitable for use in many corrosive environments. Fasteners made from Types 304 and 305 stainless steels are compliant with the 2012 and 2015 IBC and IRC.
See Passivation of Stainless-Steel Fasteners below.*

Severe Level of Corrosion Resistance

Type 316 Stainless Steel

Type 316 stainless steel is a nickel-chromium austenitic grade of stainless steel with 2-3% Molybdenum. Type 316 stainless steel is not hardened by heat treatment and is inherently nonmagnetic. It provides a level of corrosion protection suitable for severe environments, especially environments with chlorides. Type 316 stainless-steel fasteners are compliant with the 2012 and 2015 IBC and IRC.
See Passivation of Stainless-Steel Fasteners below.*

Class C Hot-Dip Galvanized, ASTM A153

Class C hot-dip galvanization is a coating that meets the requirements of ASTM A153, Class C, which is a minimum average of 1.25 oz/ft2 [381 g/m2] of zinc applied by a hot-dip process. Hot-dip galvanized fasteners are compliant with the 2012 and 2015 IBC and IRC.

Copper

Copper wire used for the manufacture of fasteners is in compliance with the material specifications of ASTM F1667. Copper fasteners meet the requirements for use in preservative-treated and fire-retardant-treated wood as stated in the 2012 and 2015 IBC and IRC. Compatibility with proprietary wood treatment chemicals should be verified against applicable evaluation reports.

Silicon Bronze

Silicon bronze is a copper alloy with silicon as the alloying element. Silicon bronze fasteners meet the requirements for use in preservative-treated and fire-retardant treated wood as stated in the 2012 and 2015 IBC and IRC. Compatibility with proprietary wood treatment chemicals should be verified against applicable evaluation reports.

*Passivation of Stainless-Steel Fasteners - Stainless steels are designed to naturally self-passivate by forming a chromium oxide layer. Corrosion resistance of some stainless-steel fasteners is enhanced by a post-fabrication passivation process. The passivation process uses an acid bath to strip free iron from the surface chromium to the oxide form.

General Note About Salt Spray Testing

Salt spray testing in accordance with ASTM B117 is not intended to represent real-world corrosion performance of fastener coatings. It should only be used for comparative evaluation between like products. Many variables may affect the outcome of the salt spray test such as base material, fastener features, coating and the material where it is installed.