Variety of surface treatment styles for stainless steel plates

Bright annealed (BA or 2BA) stainless steel sheets are manufactured by heat treatment (annealing) in a controlled atmosphere furnace. Its appearance resembles a mirror. Applying a minimum amount of rolling pressure to the face of these stainless steel plate enhances flatness and uniformity of finish without significantly reducing the thickness of the panel. Bright annealed stainless steel is sometimes polished to obtain a more mirrored finish.

It is often specified for applications requiring a highly reflective surface. Common applications are appliance trim, appliances, building components, auto trim, builder hardware, chute liners, commercial refrigerators, cookers, fishing equipment, tableware, food processing equipment, general hardware, highway trailers, transit vehicles, radiant heating Appliances, Range Hoods, Scientific Instruments, Surgical Instruments, Textile Finishing Equipment.
Finish No. 3 was characterized by short, relatively rough, parallel polish lines that ran uniformly along the length of the coil. It is obtained by mechanical polishing with progressively finer abrasives or by passing the coil through special rollers that press patterns into the surface simulating the appearance of mechanical wear. This is a medium reflective finish. When mechanically polishing, a 50 or 80 grit is usually used initially, while the final finish is usually achieved with a 100 or 120 grit. Surface roughness is typically Ra 40 microinches or less. Often used in beer equipment, food processing equipment, kitchen equipment, scientific instruments.
The No. 4 finish is characterized by short parallel polish lines that run evenly along the length of the coil. Obtained by mechanical polishing with progressively finer abrasives on a No. 3 polisher. The final finish can be anywhere between 120 and 320 depending on the requirements of the application. Higher grit counts produce finer polish lines and a more reflective surface. Surface roughness is typically Ra 25 microinches or less. Typical applications for this surface are appliances, architectural siding, beverage equipment, marine fittings, bus stops, clean rooms, column covers, dairy equipment, elevator doors and interiors, escalator trim, food processing equipment, furniture, road tankers Trailers, hospital surfaces and equipment, instrumentation or control panels, kitchen equipment, baggage handling equipment, mass transit equipment, restaurant equipment, sinks, sterilizers, storefronts, fountains.
Finish No. 6 is a matte silver-white finish with relatively short linear polish lines. It has a lower reflectivity than No. 4 finish. It is manufactured by Tampico, Brush No. 4 Finish Paper in Oil and Abrasive Medium. This decoration is sometimes seen in stainless steel architectural applications.
The No. 7 finish is highly reflective and has a mirror-like appearance. Surface buff to 320 grit No. 4 for up to 10 minutes, but existing grit lines will not be removed. Remnants of fine polish lines can often be seen by observers a few feet away from the panel. Common applications are column caps, trim panels, wall panels.
No. 8 finish is the most reflective finish covered by ASTM standards. It was produced in the same way as the No. 7 finish, except that the polishing lasted another five to ten minutes. The grit lines are less pronounced compared to the finish on the 7, but they can be seen if the finish is done on close inspection. The final finish is a mirror image, but not a perfect mirror. Applications are clean rooms, column covers, mirrors, trim panels, press panels, reflectors, signage and wall panels.