Polishing

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Info coming soon...

The stainless steel is cold rolled, softened and descaled, similar to the process of a 2D finish. It then receives a final light pass on polished rolls known as a ‘pinch pass’. The steel remains gray in appearance, but the final pass on polished rolls produces a smoother, brighter surface than 2D finish. This is a general purpose, cold rolled finish; it is suitable for a wide range of stainless steel applications and wide range of subsequent polishing processes, such as satin finishing. Typical uses for 2B finish include non-decorative or functional sheet metal products, industrial refrigeration equipment, chemical plant and plumbing fixtures.

Bright Annealed (BA) is produced by heat-treating (annealing) steel with a controlled atmosphere furnace. After heat-treatment, the steel has a reflective, mirror-like appearance, but may also have some imperfections and cloudiness. BA stainless steel can be buffed to attain a more reflective finish, and is often specified for applications where a highly reflective surface is desired.

No. 3 Polished Finish is also known as grinding, roughing or rough grinding. This finish is coarse, and usually is a preliminary finish applied before manufacturing. No. 3 is an intermediate polished finish, with examples including grinding gates off of castings, deburring or removing excess weld material. It is applied by using 36–100 grit abrasive.

No. 4 Finish is produced with short, parallel polishing lines. These lines extend uniformly along the length of the coil. It is obtained by mechanically polishing a No. 3 finish with gradually finer abrasives. Depending on requirements, the final finish is obtained using between 120 to 320 grit. High grit numbers create finer polishing lines and more reflective finishes. This is a general-purpose finish, and is widely used for kitchen/restaurant equipment, food processing, and dairy equipment.

No. 6 Finish is a dull, silver white finish with relatively short linear polishing lines. The No. 6 finish has a lower reflectivity than No. 4 finish, and is produced by Tampico brushing a No. 4 finish sheet in an oil and abrasive medium. This finish often used for stainless steel architectural projects between 1930 – 1990. It is no longer produced by toll polishing houses, but custom fabricators sometimes apply it to small projects.

No. 7 Finish is very reflective and has a mirror-like appearance. A No. 4 Finish that has been polished with a 320 or finer grit and then is buffed but existing grit lines are not removed. Fine polishing lines can often be seen by an observer standing several feet from a panel. This finish is often used for ornamental purposes, such as trim, column covers, or wall panels.

No. 8 Finish is the most reflective finish covered by ASTM standards. It is produced using the same process as No. 7 finish except that buffing continues for an additional time. The grit lines are much less visible than the No. 7 finish, but can still be seen if examined closely. The resulting finish is the closest finish to an actual mirror, but is not perfectly reflective.