No. 4 Finish is produced by rolling stainless steel that has been heated prior to rolling (hot-rolling). This is followed by a heat treatment that produces a uniform microstructure (annealing) and ensures that the stainless steel will meet mechanical property requirements. After these processing steps, the surface has a dark non-uniform appearance called “scale”.
Surface chromium has been lost during the previous processing steps, and, without removal of the scale, the stainless steel would not provide the expected level of corrosion resistance. Chemical removal of this scale is called pickling or descaling, and it is the final processing step. A No. 4 finish has rough, dull, and non-uniform appearance. There may be shiny spots were surface imperfections were removed by grinding. It is generally used in industrial applications, such as equipment for elevated temperature service.
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1. Tolerance:±1%
2. Processing Service: Bending, Welding, Decoiling, Punching, Cutting
3. Steel Grade:310S, 410, 316Ti, 316L, 441, 316, 321, 304, 304L, 904L
4. Price Term: CIF, CFR, FOB, EX-WORK
