What does electropolishing do to stainless steel?

Electropolishing stainless steel is a “reverse plating” process that uses an electrochemical solution to remove the outer skin of a metal part. Electropolishing stainless steel significantly, especially 300 and 400 series stainless steel, improves a part’s corrosion resistance, leaving it with a lasting bright finish.

Can you cast stainless steel?

Stainless steel can be cast or wrought. The main difference is in how it is formed into a final product. Cast stainless steel is made by pouring liquid metal into a molding container with a specific shape. If they are a small component of a larger product the casting may go to other factories for assembly.

Can you electropolished steel?

Most metals can be electropolished successfully, however, the best results are obtained with metals that have fine grain boundaries that are free of non-metallic inclusions and seams, such as electropolished stainless steel. Those metals having a high content of silicon, lead or sulfur are usually troublesome.

What is the difference between electropolishing and passivation?

Although both employ chemical baths in their operations, electropolishing also incorporates the use of an electrical current to remove microscopic surface layers of material to achieve a smooth finish, while passivation is non-electrolytic and produces a contaminant-free surface finish with enhanced corrosion …

Does electropolishing prevent rust?

Electropolishing removes the impurities on the metals surface, while producing a uniform finish that is occlusion free and microscopically smooth. By drawing out the impurities you prevent corrosion and rust. Metal corrosion is greatly enhanced the electropolishing process.

What is passivation on stainless steel?

Passivation is a widely-used metal finishing process to prevent corrosion. In stainless steel, the passivation process uses nitric acid or citric acid to remove free iron from the surface. The chemical treatment leads to a protective oxide layer that is less likely to chemically react with air and cause corrosion.

What makes stainless steel attractive?

The chromium and molybdenum content is high, with 22% to 25%, and up to 5%, respectively, with very low nickel content. The duplex structure gives the stainless steel many desirable properties.

What is ferritic stainless steel used for?

Group 4 ferritic stainless steels contain higher amounts of molybdenum, further improving their corrosion resistance. This type of steel is commonly used for high-moisture applications like exhaust systems and hot water tanks.

Does electropolishing improve surface finish?

The electropolishing process may improve a surface finish by up to 50%. The electropolishing reaction removes material while it improves surface roughness. Because of the material removal, process runtimes are often limited to maintain dimensional tolerances.

When should you passivate stainless steel?

Passivation is required to restore or enhance the chromium oxide film on the stainless steel surface when it has been manipulated by surface finishing, welding, grinding, external contamination, etc.

How do I check my stainless steel passivation?

The copper sulfate test detects the presence of iron and iron oxide on the surface of passivated stainless steel. Within a six-minute test, a copper film will form if free iron is present.

What happens when stainless steel castings are electropolished?

Electropolished stainless steel castings will be brightened but will not be as smooth as strip stock nor obtain the same mirror finish. The process decontaminates and passivates the metal surface. Note: During electro-polishing, the surface of the casting will be removed and may expose sub-surface porosity.

How is electropolishing used in the polishing process?

Electropolishing is an electrochemical finishing process that removes a thin layer of material from a metal part, typically stainless steel or similar alloys. The process leaves a shiny, smooth, ultra-clean surface finish. Also known as electrochemical polishing, anodic polishing or electrolytic polishing, electropolishing is especially useful

Which is the most common metal used in electropolishing?

Electropolishing of stainless steel is the most common use of the process. Although nearly any metal will work, the most commonly electropolished metals are 300- and 400-series stainless steel.

How long does it take to electropolish stainless steel?

The stainless steel item that is being electropolished is the anode in this direct current cell. Electrolytes used are usually mixtures of phosphoric and sulphuric acids. The process takes around 10-20 minutes. The process induces preferential dissolution of the ‘peaks’ or high spots on the surface of the work piece.