How To Prevent Corrosion When Welding Stainless Steel

If you are welding stainless steel for the first time, you might discover that it is easier to weld than many other materials and can be welded with many processes. However, there are still many things that can go wrong when welding steel.

Keep Stainless Steel Separate from Other Steels

While stainless steel is a steel, it does not weld in the same way as carbon steel. Do not weld stainless steel and carbon steel at the same station because you may accidentally introduce carbon to the stainless steel, which can lead to premature welding. Instead, you will want to use separate tools for each type of steel.

Be Careful When Welding Stainless Steel

Stainless steel has an oxide film that protects the steel while it is in service. Once this has become damaged, the stainless steel might become vulnerable to corrosion. Because of the high temperature at which stainless steel is welded at, a welder might introduce defects.

Keep Your Stainless Steel Clean When Welding

To avoid introducing defects, be careful to avoid slag, undercut, stray or splatter arc strikes. The best ways to prevent these is to keep your work area, materials and equipment clean. Oil, grease, and crayon marks can lead to a poor weld quality.

Perform a Mechanical Cleaning if Necessary

If the stainless steel has surface contamination before being welded, you should perform a mechanical cleaning to avoid introducing defects. Use a wire brush that has only been used to clean stainless steel. Another option is to use an abrasive disc that has not been used yet.

Chemical Cleanings Remove the Most Stubborn Contaminants

There are various products you may treat stainless steel with to clean it and reduce the risk of defects. Treating the stainless steel with a dilute nitric acid solution will remove the contaminants. Afterward, remember to grind and machine the piece.

Certain contaminants, such as embedded iron, can be removed with acid pickling. Through the process of electropolishing, the affected area will be smoothed out. Then, a protective film will form naturally over the area, protecting it from corrosion.

Stainless Steel Must Be Properly Maintained When in Service

Stainless steel is often seen as a reliable and durable material. While this is usually the case, failing to clean and maintain the stainless steel or introducing defects through the welding process will cause your stainless steel piece to weaken and will eventually need to be replaced.

For more information, contact your local residential steel shop.