Metal the hydraulic metal structure of steel structure

When the air relative humidity is more than 85%, the metal surface at less than 3 ℃ above the dew point temperature shall not construction.

1. The preliminary control

Sandblasting before, according to the steel surface before coating corrosion level and descaling grade, on the substrate surface corrosion of metal structures assessed level.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;Abrasive particle size to 0.5 ~ 1.5mm appropriate, shall be dried before the screening, stored in a shed, indoor, mesh size:Particle size of the coarse screen 40 ~ 48 hole/cm2 (1.2 mm), 372 ~ 476 fine screen hole/cm2 (size 0.3 mm).

After blasting plan was finalized, abrasive optional river sand, quartz sand or a mixture of both.

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

Blast in view of the hydraulic metal structure for outdoor operation, 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.