12. Corrosion Resistance and Anchor Materials

Conditions Change…

So Does Technology.

From the original self-drill anchor to the Epcon^® Ceramic 6™ adhesive anchoring system, ITW Ramset/Red Head has led the way in developing products for your specific anchoring applications. Since 1910, we have created the technology and the products to meet your needs. Today you can choose from a variety of anchors and technologies — from carbon and hot-dipped galvanized to the most sophisticated adhesive anchoring system in the world — Epcon Ceramic 6.

What’s the best anchor for today’s

more corrosive environments?

As environments surrounding anchoring applications have become more corrosive, we believe architects, engineers and installers could use a handy reference piece to help in the anchor selection process. That’s one of the reasons we developed this technical guide section.

Though technology has changed and environments are more corrosive, carbon steel and hot-dipped galvanized anchors are still the best choice in certain applications. And that’s another reason for these guidelines. To help you save money and reduce the costs of your projects by not over-specifying, for example, 316 stainless steel, when 304 stainless steel is appropriate. The following information and guidelines can help you specify the right material on every job without losing money…or time, in the process.

What Causes Steel Anchors to Corrode Over Time?

There are four physical factors — pollution, rainfall/humidity, air temperature and galvanic erosion — that affect the corrosion rate.

Galvanic Erosion

Also called bi-metallic corrosion, galvanic erosion occurs when two metals of different electro-chemical potentials come in contact. An electrical circuit is set up if the junction is bridged by moisture and the resultant current will considerably increase the corrosion rate of the less noble material.

Galvanic Metals and Alloys

As indicated, 304, and 316 Stainless Steels are among the most noble metals available to resist corrosion and galvanic reaction.

Stainless Steel

Application Guidelines

There are many variables that characterize a corrosive environment (i.e., chemicals and their concentrations, atmospheric conditions, time and bi-metallic corrosion). While it is difficult to select which material to use without knowing the exact nature of the environment, there are guidelines that can be followed.

• Carbon Steel with Zinc Plating — meets ASTM B633 specifications for electroplating of 5 micrometers approximately equal to .0002” thickness. This material is well suited for non-corrosive environments.

• Carbon Steel with HDG (Hot Dipped Galvanizing) — meets ASTM A 153 specifications for hot-dipped galvanizing less than or equal to 45 micrometers approximately equal to .002”. It is highly recommended for damp, humid environments near coastal regions.

• Type 304 Stainless Steel — serves many applications well. It withstands rusting in architectural and food processing environments (except high temperatures involving high acid and chloride) and resists organic chemicals, dye stuffs and many inorganic chemicals.

• Type 316 Stainless Steel — contains more nickel than Type 304, and 2-3% molybdenum, which gives it better corrosion resistance. It is especially more effective in chloride environments that tend to cause pitting.

Anchor Selection Guide

The best approach in effectively combating the destructiveness of corrosion in a fastener system is prevention. Stop corrosion before it starts. And start by specifying the right material.