Stainless Steel Fasteners In Aluminum

Socket head cap screws.

Stainless steel fasteners in aluminum.

We specialize in miniature hobby screws in metric and standard sizes and have a wide variety of materials from anodized aluminum screws stainless steel plated and alloy steel screws to nylon. Hardened steel bolts especially when zinc plated rarely gall. Fasteners with damaged threads and fine threads are particularly prone to galling. However stainless steel is reactive with aluminum and when a stainless steel screw is in contact with an aluminum base metal the aluminum is likely to corrode.

This can lead to an extended life of the stainless steel. This results in the aluminum weakening. However the dissimilar nature of these two metals puts them at risk of getting corroded resulting in their destruction altogether. The corrosion of the fastener is increased by the base metal.

Aluminum if left on. It is no doubt that stainless steel screws are the best when it comes to holding together materials such as aluminum sheets so that when faced with a variety of elements they do not break open. We have found the most risk of galling is with larger threads m16 upwards and also when using nyloc nuts. Aluminum hates the fine thread series always heli coil those threads.

Galling is most often seen in stainless steel especially when using lock nuts aluminum and titanium. Our aluminum screws are made at our facility in the usa. An example of the safe use of stainless steel fasteners with aluminum would be where stainless steel bolts are used to secure aluminum roadway parapet guards. If the bolts don t gall and snap off going in they will do so coming out.

In this case the surface area of the aluminum is so large relative to the surface area of the stainless steel bolts that there is a very low risk of major corrosion. Fastener material steel zinc plated stainless steel type 410 stainless steel type 302 304 316 aluminum base metal zinc galvanized zn al coated steel a c c b aluminum a 1not recommended b a steel cast iron a d c b a brass copper bronze a d e a b a e stainless steel 300. Top stainless fastener engineers recommend that all stainless steel threads should be lubricated before being assembled to reduce the risk of galling this is when threads lock up. Screws treated with a high quality coating consisting of zinc and aluminum.

This weakened aluminum causes it to deteriorate at a much faster rate. We ship to canada and internationally daily. When aluminum and stainless steel are used in an assembly together the electrons from the aluminum will begin to transfer into the stainless steel. Never use self locking heli coils or any other self locking inserts or clinch nuts with stainless steel threaded fasteners.

Use stainless heli coils with stainless fasteners in aluminum. As is the case with carbon steel screws a plated stainless steel screw is less likely to corrode aluminum.