Chemical Passivation Vs. Electropolishing Appliance Parts

Household and consumer appliances are part of a highly competitive industry, and manufacturers must balance the dual priorities of meeting specific price points while creating quality products. This in mind, they must cut costs while maintaining reliability. In many cases, manufacturers choose chemical passivation over electropolishing as a way of keeping costs down. Chemical passivation, however, does not provide the same results as electropolishing, and it shows. The cost-effective 400-series stainless steel alloys used in appliance manufacturing offer relatively low corrosion resistance, and as a result, more appliance parts used in corrosive environments develop rust. When this happens in the field, the manufacturer is saddled with costly warranty repairs and risks alienating customers.

Electropolishing Appliance Parts for Finish and Corrosion Resistance

A notable example of an appliance part that we electropolish is a 430 stainless steel auger. This part is made by a major refrigerator manufacturer, who uses it in an automatic ice machine. While the 430 SS is strong enough for moving ice, like other 400-series stainless steels, it is not particularly corrosion resistant. Electropolishing appliance parts like this one removes the outermost layer of material from the metal, taking with it the carbon steel contaminants embedded in the pores from forming and machining. If not removed, these contaminated areas become initiation sites where corrosion develops. In addition to the improved corrosion resistance, electropolishing gives the part a smooth, shiny surface finish that prevents ice from sticking and improves the appliance’s function.

How Electropolishing Appliance Parts Improves Performance

Another example of how electropolishing appliance parts improves their performance is a washing machine component that we electropolish. This part is a 431 stainless steel hinge that fastens a lid to a washing machine. After being formed, machined and annealed, the part has a visible heat tint that the manufacturer needs electropolishing to effectively remove. Additionally, given the part’s prolonged exposure to water, the manufacturer is concerned about the material corroding. By electropolishing the part, we removed the heat tint, leaving behind a bright, corrosion-resistant finish. Testing has proven that when subjected to salt spray testing, electropolished stainless steel is more than 30 times more reliable than chemical passivation.