<input id="uauy4"></input> (1) weathering steel: corrosion resistance than ordinary steel steel structure called weathering steel, generally contain phosphorus, copper, nickel, chromium, titanium and other metals, the metal surface to form a protective layer to improve the corrosion resistance. Low temperature impact toughness is better than the average structural steel. Standard is "weathering steel welded structure" (GB4172-84).
(2) hot-dip zinc: hot dip galvanized steel member is immersed in the rust after about 600 ℃ high temperature melting molten zinc, the steel member attached to the surface layer of zinc, zinc layer thickness of 5mm the following sheet not less than 65μm, thick board of not less than 86μm. which play an anti-corrosion purposes. The advantage of this approach is durable long life, high degree of industrialization, quality and stability. They have been used by a large number of atmospheric corrosion is more serious and difficult to repair outdoor Foshan steel structure. If large transmission tower, communications tower. In recent years, large numbers of light steel structure system, pressure plate and the like. Also more use of hot-dip zinc corrosion. The first procedure is a hot-dip zinc pickling rust, then wash. The two processes are not completely corrosion will stay hidden. It must be treated thoroughly. For steel designer, you should avoid having to design a member with bonding surface to avoid acid or acid wash is not complete without a net bonding surface of the gap. Galvanized surface yellow water flow caused by the phenomenon. Hot-dip zinc is at high temperatures. For the ends of the tubular member should be allowed to open. If the inner tube closed at both ends will cause the expansion of the air leaving the head plate burst, causing accidents. If liquid zinc closed at one end is poor circulation, easy to accumulate in the tube.
(3) thermal spray aluminum (zinc) composite coating: This is quite a hot-dip zinc corrosion effect of long-term corrosion protection methods. Specific approach is to steel member surface for sand-blasting to the surface exposed metallic luster and roughened. Then acetylene - oxygen flame will continue to send aluminum (zinc) wire melts and blowing with compressed air attached to the surface of steel components, to form a honeycomb of aluminum (zinc) coating layer (thickness of about 80μm ~ 100μm). Finally, fill the pores with an epoxy resin or neoprene paint and other coatings, to form a composite coating. This method can not be in the inner wall of the tubular member construction, which must be done at both ends of the tubular member hermetically sealed to the inner wall will not corrode. The advantage of this process is adaptable component size, component shape and size almost unlimited. Great to as Gezhouba locks also use this method of construction. Another advantage is the thermal effect of this process is local, bound, and thus will not produce thermal deformation. Compared with hot-dip zinc, this method is less industrialized, large sand sprayed aluminum (zinc) labor intensity, quality is also susceptible to mood changes the operator.
(4) Coating Method: corrosion coating method is generally not as good as a long-term corrosion protection method (but even fluorocarbon coating anti-corrosion life of up to 50 years). So for indoor outdoor steel or steel are relatively easy to maintain more. It is a low cost, are used outdoors, but the cost for maintenance. The first step in the construction of the law rust coating. The quality of the coating depends on thorough rust. So demanding coating usually used blasting abrasive blasting, exposing the metal luster, remove all rust and oil. Site construction manual rust coating available. Coating selection should consider the surrounding environment. Different coatings for different corrosion conditions have different tolerance. Primer coating generally (layer) and top coat (layer) of the points. Primer containing powder, less binder. Filming rough, with strong adhesion to steel, combined with a good finish. Finish the base material and more, film glossy primer to protect against corrosion, and capable of weathering. Or not having compatibility problems between different paint, they should pay attention to the compatibility of the coating before and after the use of different time. Construction coatings have the appropriate temperature (between 5 ~ 38 ℃) and humidity (relative humidity less than 85%). Coating construction environment less dust, member surface can not have condensation. After the coating may not rain within 4 hours. Coating generally do 4 to 5 times. The total dry film thickness of the outdoor engineering 150μm, interior works for 125μm, tolerance to 25μm. At the beach or at sea, or in strong corrosive atmosphere, the total dry film thickness can be thickened to 200 ~ 220μm.
(5) cathodic protection: additional steel surface in Foshan more active substituted metal corrosion of steel. Commonly used in underwater or underground structures.
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