Stainless steel is widely used by various industries, including automotive parts and systems, shipping containers, building interiors and exteriors, surgical tools, kitchen cutlery and cookware, household appliances, medical implants, aircraft components, and more. It is durable, aesthetically pleasing, and resistant to corrosion, heat, and chemicals. However, it is not impervious to the effects of time, which makes polishing stainless steel an important factor for maintenance.
Benefits of Polished Stainless Steel
While stainless steel is well-known for its distinctive sheen, it can lose its luster with age. Polishing stainless steel not only helps keep it looking good, but also provides other benefits:
Aesthetics:
Polishing improves the surface quality of the metal, helping stainless steel maintain its lustrous appearance. When combined with buffing, it can create mirror-like finishes.
Reduces corrosion:
Polishing helps reduce the number and size of crevices in the metal that encourage rust.
Removes contaminants:
Polishing stainless steel removes contaminants from the surface, even if they are invisible to the naked eye. This is particularly important for certain applications.
In metallurgy, metals are often polished to enable better observation of their crystalline structures, defects, and discontinuities under a microscope.
Methods of Polishing Stainless Steel
There are multiple ways to polish stainless steel, with the easiest method being to apply abrasives by hand. However, this method is often inefficient and can result in inconsistent quality, especially on a larger scale. If the steel is already dented or scratched, it will require treatment before polishing to avoid highlighting the imperfections. The choice of tools and techniques depends on the desired finish.
When seeking a professional finish for stainless steel, using the right equipment is crucial. The equipment should maintain a constant speed, while the abrasive used should have a certain coarseness to effectively polish the steel. The type and scale of the project also determine the required equipment. Smaller jobs may only require a drill or handheld grinding tool, while larger projects may necessitate a grinder with a polishing wheel. For large-scale polishing, custom machinery may be needed to automate the process. The following are common finishes for polished stainless steel:
Mill or Matte Finish
This unpretentious finish requires less time, effort, and expense compared to others. Mill finishes normally appear somewhat incomplete but can serve as a starting point for a longer process to achieve a more attractive appearance. It is often used for practical applications such as kitchen sinks or workbenches. To achieve a matte finish, the steel is rolled through special dies or rollers.
Brushed Finish
Brushing stainless steel creates decorative patterns consisting of delicate parallel lines. Unlike the typical reflective sheen of stainless steel, this finish works well in areas exposed to bright indoor lights or intense sunlight. It is often used for kitchen appliances. However, brushed finishes may reduce the steel’s resistance to corrosion, so rust-proofing may be advisable depending on the application. Achieving uniform lines in brushed finishes requires a high-grade abrasive.
Mirror Finish
This highly reflective finish is the epitome of stainless steel’s appearance. It effectively hides welded metal and makes cleaning easier. Achieving a mirror finish requires a wheel or at least a 320-grit belt for polishing stainless steel.
Gloss Finish
Polishing stainless steel to a gloss finish improves its corrosion resistance by smoothing crevices where rust can accumulate. The chrome-like shine of this finish is ideal for automotive parts and requires proper surface preparation. Using a high-quality buffing compound and a grinder with a polishing wheel can further enhance the shine, resembling a mirror-like finish.
