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Shot Blast cleaning is the most commonly used method for preparation of steel surfaces. This effectively removes rust, scale, slats, and makes surface rough (rough surface is called profile). Profile increases the effective surface area of the steel. The cleanliness achieved is assessed to by Swedish standard from a set of photographic slides in Swedish standard (SIS) showing examples of the common terminology of white-metal, near white-metal, etc. Typically, SA 2½ is used for pipelines (equivalent to NACE N°2).
It is important to remove grease or oil contamination prior to blast cleaning. Solvent cleaning, burn-off, etc., are commonly used for this purpose. In the blast cleaning process, a blasting wheel uses centrifugal force to propel the abrasive against rebar in controlled direction, speed and quantity. The equipment is equipped with 4 blast wheels. 2 blast wheels are mounted on the top of the cabinet and positioned above the pass line of the work and the other 2 Blast wheels are mounted in the bottom of the cabinet positioned below the pass line of the rebar. Blast Wheel position and angel are strategically designed in such a way that the abrasive blast pattern covers the entire surface multiple re-bar. |