Summary of steel structure derusting method and grade standard
Steel structure derusting method and grade standard requirements
Abstract sandblasting derusting: using of high pressure air to bring out the quartz sand spray to the surface of a component to achieve a rust method. The sources of quartz sand are: river sand, sea sand and artificial sand
Steel structure derusting method and grade standard requirement
There are roughly the following methods of rust removal:
A, shot blasting: using high-speed operation mechanical equipment throwing certain size of the steel balls by centrifugal force, Steel balls thrown out with the components collision violently to achieve the purpose of eliminating the surface corrosion of steel. The steel balls varieties are: cast iron pills and steel cutting pill ,cast iron pills is using molten iron in the jet and rapid cooling in the case of the formation of particle size in the 2 ~ 3mm iron pills, the surface is very round. It is relatively cheap but less durable. In the process of shot blasting repeated,iron balls were crushed and excluded as dust. Wire cut pill is made of scrap steel wire rope cut into 2mm small pieces, its surface with sharp corners, derust effect is relatively high and not easy to break, long life extension but the price has improved. The latter's shot blasting surface is more rough.
B, shot peening rust: using high pressure air to bring out the ball shot to the surface of the component to achieve a rust method.
C, sand blasting: using high pressure air to bring out the quartz sand spray to the surface of a component to achieve a rust method. The sources of quartz sand are: river sand, sea sand and artificial sand. Sand costs are low and a wide range of sources, but the environmental pollution; rust completely rely on manual operation, rust after the surface roughness of the components is small, difficult to meet the requirements of the friction coefficient. Sea sand should be used to remove its salt before use.
The above two kinds of derusting methods require less than 85% of the ambient humidity.
D, pickling derust: pickling derust is also known as chemical derust, the principle is using the acid and metal oxide to produce chemical reaction, the metal oxide dissolved, and remove the corrosion and dirt on steel surface. But pickling can not get the effect as shot blasting or shot peening roughness surface. And after pickling derust must be cleaned by a lot of water and passivation treatment; it formed a lot of waste water, waste acid and acid mist, that’s caused environmental pollution. If not handled properly will cause the metal surface erosion, the formation of pitting. It’s rarely used at present.
E, manual and power derusting: simple tool for easy construction. But the labor intensity, derust effect is poor. It’s only used under the conditions of other methods are not available and local use. Such as individual components of the dressing or the local use of installation site. The common tools are: grinder, blade, wire brush, emery cloth and so on.