The process of Disa sand blasting room for processing workpieces:

1.Preliminary control

Carefully check the surface of workpiece before blasting, remove welding slag, splashes and other attachments, as well as clean surface grease and soluble contaminants. Blasting should be performed only on the workpieces that needs to be clean.

2.Tool control

When sand blasting room is operated, the air pressure of air compressor is 6.0x105-6.5x105Pa and the range of the air pressure is 0.5x105-1.0x105Pa. The general air pressure of sand bucket is 4.5x105-5.5x105Pa and must not smaller than 4.0x105Pa. Before sand blasting, whether the pressure vessel manufacturer holds production license that is issued by the authorities, whether the protective clothing that is worn by sand blasting workers, safety belt (rope) and oxygen supplying device are safe or not as well as the wearing of nozzle should also be checked. Nozzles should be replaced when the orifice diameter is increased by 25%.

3.Conditional control

The compressed air in shot blasting room must be processed through cooling device and oil-water separator in order to keep dry and oil-free. The oil-water separator must be cleaned regularly. The distance between the nozzle and the base steel surface preferable is 100-300mm. The non-blasting areas should be protected in a covered mode before sand blasting. The normal inclined angle between the blasting directions and the base steel surface preferably is 15-30 degree.

After sand blasting and de-rusting and before the next process, if it is rainy or other cases that result in a wet base steel surface, construction shall be carried on when the environment meets construction conditions and water on the surface is fully dried by dry compressed air. If sand blasting needs to be carried out again, the requirement for abrasives can not be lowered, so as not to reduce roughness.

The nozzles can not be kept somewhere for a long time when sand blasting room is operated. Jobbing operation should be avoided, but the blasting area can not be too large at a time. The requirement for time interval between coating or thermal spraying process and surface pretreatment process. The areas that can not be blasted by nozzles should be de-rusted by a hand tool or a power tool.

4.Abrasive control

The abrasives used for shot blasting room are required to be hard, dry with corner angles and without dirt and other impurities. It preferably is silica sand and coarse river sand is also applicable. The transportation condition, unit price and recycling capacity, and the like should be considered. The diameter of the grit preferably  is 0.5-1.5mm. The grits must be dried before filtering and stored in a shed and indoors. The sieve pit size: coarse screening: 40-48 sieve pits/ cm2 (diameter 1.2mm), fine screening 372-476 sieve pits/ cm2 (diameter 0.3mm).

5.Quality control

Complete checking should be performed on the derusting parts, then the cleanliness and roughness of the base steel surface should be checked. The parts that are difficult to process should be paid more attention to. The requirements by using a manual tool or power tool to carry out derusting can be properly reduced. When the cleanliness and roughness of the base steel surface is checked, touching by hand is forbidden, and blasting should be performed under good scattering sunlight and sufficient artificial lighting to avoid missing inspection.