The surface finish requirements of material under ASTM: Specifications A167, A176, A240/A240M, A263, A264, A265, A666, A693, A793, and A895 are given in ASTM A480/A480M-05 Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip.
"M" indicates a Metric specification (SI units).
However, I don't have the 2005 revision of ASTM A480/A480M; my older copy has the finishes described and shown (with photos) at
"3" possibly corresponds to the previous No. 3 finish: Intermediate polished finish, one or both sides.
From SSINA:
"No. 3 Finish is characterized by short, relatively coarse, parallel polishing lines, which extend uniformly along the length of the coil. It is obtained by either mechanically polishing with gradually finer abrasives or by passing the coil through special rolls, which press a pattern into the surface that simulates the appearance of mechanical abrasion. It is a moderately reflective finish. When mechanically polishing, 50 or 80 grit abrasives are typically used initially and the final finish is typically achieved with 100 or 120 grit abrasives. The surface roughness is typically Ra 40 micro-inches or less. If a fabricator needs to blend in welds or do other refinishing, the resulting polishing lines are usually longer than on product polished by a producer or toll-polishing house."
"H" possibly indicates work Hardened; i.e., cold rolled, as in the EuroNorm standard EN10088/2. See "Surface Finishes" (1 page) at
hey adamu, kenvalach is on the right track. most stanless steel sheets are sold by ga and finish. when orderd it commonly comes in a 2-b finish.the 2 refers to the grade of the finish. it is a plain dull finish. a #4 finish is the mill or brushed finish that kenvalach is refering to finishing with 100-120 grit.this is ussally done on counter tops, stoves. refrigorator, custom hoods and hand rails there are also #8 and #10 finishes. these finishes are when the metal is polished. when completed it will have the look of a mirror. the finish you are looking for would be diffrent that of a #4. You can try calling industrial metal supply in santa fe spring, ca or relianc metal center in national city ca. they should have the exact answer you are looking for.
