Smooth clean surface (SCS) is a process applied to

hot rolled In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness, to make the thickness uniform, and/or to impart a desired mechanical property. The concept is simil ...

sheet metal and coils to remove nearly all

mill scale Mill scale, often shortened to just scale, is the flaky surface of hot rolled steel, consisting of the mixed iron oxides iron(II) oxide (FeO), iron(III) oxide (), and iron(II,III) oxide (, magnetite). Mill scale is formed on the outer surfaces o ...

and clean the steel surface. The SCS process feeds hot rolled sheet steel, either as individual blanks or as a continuous strip that is uncoiled, into the SCS "brushing machine". Within the machine the steel is passed between sets of rotating roller brushes that spin on an axis perpendicular to the sheet's direction of travel. The roller brush exterior is an engineered abrasive, similar to Scotchbrite, that makes contact with the steel under pressure. Each roller brush spins against the steel at a speed of 900 to 1000 revolutions per minute, "scrubbing away" the outer layers of mill scale –

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

and

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...

– and most of the inner layer, wustite. The remaining wustite layer is only a few micrometres thick and highly polished to a smooth surface. Three such roller brushes are typically applied to each surface of the steel sheet, for a total of six roller brushes per SCS brushing machine. Numerous spray nozzles within the brushing machine provide water to rinse the removed scale and any other debris from the steel surface and to cool the friction heat generated in the brushes. The water is filtered and re-used in this closed-loop rinsing/filtering system. The SCS process imparts a measure of rust resistance to the sheet steel, so that when exposed to a noncondensing atmosphere, its propensity to rust is markedly less than that of hot rolled steel that is not treated with the SCS process. The exact metallurgical phenomenon underlying this transformation of the surface to make it more rust resistant is not fully understood; however, it is theorized that the remaining wustite layer (chemical symbol FeO) contains a much lower proportion of oxygen than the removed

and

layers and is, therefore, more stable and less prone to oxidation when exposed to a noncondensing atmosphere. The SCS process and its attendant equipment is now paired with a related process,

eco pickled surface Eco pickled surface (EPS) is a process applied to hot rolled sheet steel to remove all surface oxides (mill scale) and clean the steel surface. Steel which has undergone the EPS process acquires a high degree of resistance to subsequent developme ...

or EPS. The EPS technology accomplishes a more complete removal of surface oxides than does the SCS process; however, it can also leave the surface with an overall rougher texture, as indicated by Ra or roughness average. The SCS process is applied directly after the EPS process to produce a smoother surface when desired.

References

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External links

''Chicago Service Center's New Smooth Clean Surface Line Improves Quality'', Coil World, March/April 2007

* ttp://www.metalcenternews.com/2007/may/mcn_0705_cs_jdm.htm ''JDM Sees SCS As Its Future'' by Myra Pinkham, Metal Center News, May 2007.
''TODOACEROS Steel Service Center in Spain''
Corrosion prevention Metalworking

References

Further reading

External links