A variety of finishes are available for both annealed and pretempered strip, with selection being guided by finished part requirements. However, for most strip applications finish is not significant, and the least expensive choice is the best one.
When annealed strip is ordered, the standard finish is No. 2 bright. This finish is so widely accepted that it is usually supplied automatically without specification. This finish offers an average reflectivity and surface roughness of 3-8 RA.
Four standard finishes are available for pretempered strip. They result naturally from the quench and tempering medium used for a given strip thickness. For most applications, the specifier will choose either scaleless and bright, or tempered, polished and colored- all of which can be produced with an RA of 3-30. Maximum scratch depth allowance is 1.0% depth of strip thickness.
A polished and colored surface is required even less often than a polished surface. At one time, colored surfaces carried some significance because they indicated the strip had received proper heat treatment. Today, this finish is primarily cosmetic.
|Scaleless||Dark tight oxide film of varying blue|
|tempered||or gray color, result of liquid or block|
|quenching & tempering.|
|Bright||Non-oxidized surface, result of|
|Tempered||Absolutely clean surface, result of|
|& polished||polishing after hardening & tempering.|
|Tempered,||Blue or straw surface color, result of|
|polished & colored||thermal treatment after polishing.|
|(blue or straw)|