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Many of sand is not very understand, in fact, sand blasting is very simple, because the sand material to a certain speed and workpiece surface, forming a certain roughness, thereby improving the coating adhesion, extend the anticorrosion fixed number of year.
If yes understand sandblasting machine please contact me. Contact Mr. Han: 15010113682
Early control..
Sandblasting before, according to the steel surface before coating corrosion level and descaling grade, matrix structure of metal surface corrosion level evaluation. Carefully check, remove welding slag, spatter and other attached objects, and cleaning the surface grease and dirt, soluble on useless welding or connection should be properly handled.
2. The abrasive control
Sandblasting derusting with sand and asked for hard particles, angular, dry water content (< 2%), no dirt and other impurities; Is good with quartz sand, coarse river sand can be; At the same time, should consider the transportation of sand fill, unit price, recycling capacity factors such as; Particle size of sand fill with 0.5 ~ 1.5 mm advisable, screening should be dried before storage in huts, indoor, mesh size is: coarse sieve 40 ~ 48 hole/cm2 (size 1.2 mm), fine screen 372 ~ 476 / cm2 (size 0.3 mm).
Abrasive cleaning solution is determined, the optional river sand, quartz sand, or both. On-the-job south reservoir and consolidate, then spray the comparison, the quartz sand and river sand according to 1:1 have to use the best cleaning effect.
3. The tools to control
Sand blasting operation, air compressor air pressure of 6.0 x 105 ~ 6.5 x 105 pa, pressure amplitude of 0.5 x 105 ~ 1.0 x 105 pa. General sand barrel pressure of 4.5 x 105 ~ 5.5 x 105 pa, shall not be less than 4.0 x 105 pa. Sandblasting before should check of the pressure vessel manufacturers hold production license issued by the relevant departments, sandblasting work wear protection tools, seat belt (rope) and oxygen supply device is safe and reliable, and the abrasion of the nozzle, when the nozzle orifice diameter increases 25% of replacement. 4. Environmental control For outdoor homework if sandblasting derusting, in addition to the dust prevention and environmental protection should be paid attention to during the construction, must also be daily testing construction site environment temperature, humidity and the temperature of metal surface, calculate the dew point, completes the construction record. When the air relative humidity is more than 85%, the metal surface at less than 3 ℃ above the dew point temperature shall not construction. 5. Process control of sand blasting with compressed air must be through the cooling device and the processing of oil-water separator, to ensure that the dry, no oil; Oil and water separator must be cleaned regularly. Distance from the surface of the nozzle to the substrate steel 100 ~ 300 mm advisable, sandblasting before for the sandblasting parts should cover protection. Direction of jet and the substrate steel surface normals to 15 ° to 30 ° Angle is advisable. After sandblasting derusting, before the next procedure, in case of rain or any other cause wet the surface of the substrate steel, to stay after construction conditions, environment is achieved with dry compressed air to blow dry surface moisture after construction, such as sandblasting again, do not reduce abrasive requirements, so as not to reduce the roughness. Sand blasting nozzle don't stay somewhere for long, sand blasting operation should avoid scattered operation, but not a jet area is too big, want to consider to coating or thermal spraying process and the time interval between surface pretreatment process requirements. To spray gun can't spray place to adopt manual or power tool cleaning. Quality control of 6.
Sand blast after the completion of the first response to the site to conduct a comprehensive inspection, second check the matrix steel cleanliness and roughness. Key check is not easy to injection parts, manual or power tool cleaning can be appropriately reduced requirements. The matrix steel cleanliness and roughness inspection, first, it is forbidden to touch; 2 it is to should be in a good or scattering sunlight illumination rather artificial lighting conditions, so as not to miss. After sandblasting derusting, metal structure surface cleanliness should reach Sa21/2, should control the corrosion of steel surface before painting class and descaling grade provide photos in comparison, comparing each 2 m2 has at least one more point. After sandblasting derusting, metal structure surface roughness should reach Ry60 ~ 100 microns, should according to the technical requirement and take corresponding roughness model, with at least seven times a magnifying glass, enlarge compared each 2 m2 has at least one more point. When using a surface roughness instrument direct measurement, each 2 m2 surface evaluation point, at least one take to evaluate the length of 40 mm, length private five points, take the arithmetic mean for the surface roughness of the value of evaluation.
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