Features and Types of Stainless Steel Sheet Finishes

  • Stainless steel has become one of the most popular and widely-used metals in the industrial, commercial and household sectors due to its unique characteristics, like strength, malleability, lustre, durability and versatility. One ideal factor that makes the metal popular is the variety of finishes that are available in the market. Stainless steel plate finishes are cold-rolled surface finishes.

     

    Stainless steel sheet finishes can be classified into various kinds. The different finishes are as follows: (Information Credit – http://www.eurosteel.co.za/index.php/stainless-steel-decorative-finishes/index.html)

     

    • 2B type: This is a bright, cold-rolled finish also known as mill finish.
    • 3 type: A medium polished surface made by 120-grit abrasive that has a grainy course running from one direction to another.
    • 4 type: This finish is obtained after treating it with a 150-grit mesh abrasive that is brighter than No.3 type but has directional grainy features.
    • 8 type: Also known as mirror finish, this finish has reflective properties like a mirror that is obtained by using finer abrasives and extensive burnishing.
    • Bright Annealed: This is sometimes mistaken to be the No.8 type but it is not as reflective or defect-free as the mirror finish. The sheets are kept under a certain atmosphere and annealed to obtain this finish.

     

    There are some things to keep in mind before choosing a certain type of finish:

     

    1. Stainless steel may also become corrosive in nature if not treated well. Corrosion issues can be brought about by contact of the steel with carbon steel tooling or an active mating part or a heat affected zone on a welded part.

     

    2. Before electropolishing, the stainless steel must undergo rigorous processes like proper macro and micro deburring. To achieve the most desired form of surface finish, the stainless steel may need to be mechanically cleaned or treated with vibratory finishing.

     

    3. Accelerated corrosion tests have shown that electropolishing after passivation makes the steel more corrosion resistant. Hence you should also opt for the passivation process if you want the best product yield.

     

    4. There are three other polishing processes that can be deployed for achieving that pitch-perfect stainless steel surface finish:

     

    • Manual polishing

    This entails the process of a skilled technician polishing the whole surface area consistently and evenly to yield a uniform, perfect finish. Electropolishing is the final step of this process.

     

    • Mechanical Polishing

    This is a costly and time-consuming process as it needs to be smeared and moved constantly and uniformly for a long period of time. It basically needs a fine grit to achieve a smooth surface.

     

    • Blasting

    This process involves the use of glass beads, aluminium oxide and sand. The materials are blasted on the surface of the metal under high pressure to remove scales from casts and heat-treated surfaces. This process dulls the finish of the metal and needs to be followed up by another polishing process, (preferably electropolishing) to brighten up the surface.

     

    Due to properties like cleanliness, elegant appearance, corrosion resistance, waterproof and rust resistance, stainless steel plates have a wide range of commercial applications.