Colored Stainless Steel Sheet Application

Coloring of stainless steel is generally limited to sheet products, although it is possible to color manufactured parts. Only the highest quality stainless steel sheets can be successfully chemically colored on a production basis.
The chemical coloring of stainless steel plate uses a mixture of chromic acid and sulfuric acid, which can form the thickness of the naturally formed passive film on the steel surface according to the soaking time. This is a two-stage soaking process that requires tight control of operating parameters and considerable operating skills to achieve the desired color consistency. The infrequent "blackening" finish can be accomplished by immersion in a molten sodium dichromate salt bath at about 400 C.
The resulting color is the result of light wave interference effects between light reflected from the surface of the thickened oxide passivation layer and light reflected from the interface between the passivation layer and the steel surface. As the film thickness increases, the resulting color sequence includes bronze, blue, black, charcoal, gold, magenta and green. The final thickness of the passivation film ranges from 0.02 microns for a bronze effect to 0.36 microns for a green effect.

A particular appeal of chemically Colored Stainless Steel Sheet is that it appears to change color under different shades and angles of artificial and natural light. However, it is important to ensure a good match between the sheets used for the multiple panel features.
Applications for these Colored Stainless Steel Sheets and panels include building exterior cladding (facades, columns, roofs, etc.), interior cladding in low-traffic areas, signs, store display panels, sculpture, and more.
If there are scratches, colored stainless steel is difficult to repair, which is why it is best for applications where these scratches and wear are relatively unlikely. However, it is feasible to cold-form colored sheets during manufacturing, as long as the surface is properly protected from scratch damage.

Joining by heat treatment (including welding) is not recommended as changes in original color are difficult to repair or mix. However, connections by cold processes such as adhesive bonding and mechanical fixing are suitable.