Weathering steel for finishing metal materials commonly used in household

1. Design precautions

(1) Pay attention to the natural conditions of the site. Indoor and outdoor, inland and coastal, different locations in different regions of the air salt content and air humidity, sunshine, architectural shape and orientation will affect the growth rate of weathering steel rust layer and rust layer composition, so more or less will show uneven rust state. For uniform color requirements, pay attention to the setting of the water outlet and the uniformity of the lighting water of the entire workpiece.

(2) Avoid water accumulation. In the water environment, the rust layer is easy to layer corrosion, pay attention to the drainage design near the bottom of the weathering steel. For example, if weathering steel is used as a planting pool, the design should pay attention to the height of the fill and the internal drainage channel to avoid the pollution and corrosion of the steel when it rains.

(3) The sample color reference of weathering steel is not large. Because in the general natural environment from the new steel plate to the formation of a stable and dense rust red protective layer takes 6 months to 1 year (with rust promoters), for some dry areas or indoor may be longer. And even to produce a simple uniform rust yellow, it takes about 1 month. In this process, the color of the components gradually transitions from bright yellow, earthy yellow, orange yellow, orange red, reddish-brown, and brown.

Therefore, when designing the weathering steel landscape, it should be designed with the last color, and communicate with Party A clearly about the color changes that will be experienced in the early stage.

(4) Weathering steel is not not corroded, but corrosion is slower, high-quality weathering steel life is 8 times that of ordinary steel (single-sided annual corrosion rate of 0.097mm), the design needs to consider a little thickness corrosion allowance.

Weathering steel gas furnace

2. Construction points

(1) Corrosion of welding points: the oxidation rate of welding points must be the same as that of weathering steel, which requires special welding materials and technology. Although the ordinary electrode can also normally weld the weather-resistant steel plate, and there will be no serious color difference after welding, the life of the weld will be much lower than the life of the weather-resistant steel plate, and it may also cause rust underwater flow pollution of the weather-resistant steel plate because the corrosion speed of the weld is too fast. Therefore, it is necessary to pay attention to the selection of special welding rods with similar weathering tempering components and matching strength and toughness.

(2) Water corrosion: weathering steel is not stainless steel, if there is water in the low concave of weathering steel, the corrosion rate will become faster, and attention must be paid to drainage during construction.

(3) salt-rich air environment: Weathering steel is more sensitive to salt-rich air environment, in such an environment, the surface protective film may not prevent further internal oxidation.

(4) Construction temperature: the surface temperature of the weathering steel workpiece is too high (over 35 degrees) and too low (less than 5 degrees), and high temperature exposure will have an adverse effect on the rust effect, especially for the coating of rust fixing agent, to avoid construction under the above circumstances.

(5) The order of installation and rust: usually in order to achieve a better overall effect, it is recommended to install the weathering steel plate and then rust treatment. First, to prevent the developed rust layer from being contaminated (such as oil, handprints, etc.) or scratched during transportation and installation; Second, the installation usually uses welding and other methods, which not only destroys the original rust layer, but also covers the welding seam without rust layer, which looks very inconsistent.

However, if the shape of the weathering steel workpiece is very complex, it is difficult to carry out rust construction after installation or the site does not allow construction, you can consider first rust and then installation. However, the premise is that the rust should be fixed first, so that there is no need to worry about contamination, and try to use the fasteners installation or screw installation to avoid the problem of new welds caused by welding.

(6) Correct construction posture: For the case of rust after installation of the workpiece, when rust treatment is carried out on the facade, the following construction posture should be taken for the corrosion agent will flow down from the top: gradually reduce the direct spraying dose from the top, and basically do not need to spray (rust from the rust promotion agent flowing down from the top), otherwise the top is prone to rust and excessive corrosion at the bottom.

3, to identify the true and false weathering steel, 

ordinary steel and weathering steel rust appearance after rust within 6 months, the difference is not obvious, because 6 months ago, weathering steel dense protective rust layer has not really grown. Therefore, in the early stage, it is difficult to distinguish the true and false of weathering steel with the naked eye, which is also an important reason for the phenomenon of fish-eye mixed beads on the market.