Basic Coating of Joint Surface of Automobile Sheet Metal Parts

2019-07-05 10:23:02

Basic Coating of Ferrous Metal Sheet

Ferrous metal sheets are easy to be oxidized and corroded due to exposure to air or contaminated with harmful substances, which results in yellow rust spots and damages the original coating. Especially in the sheet metal work process after hammering, welding and other process processing parts, it is more likely to damage the original coating protective layer, accelerate corrosion, even spraying paint film, paint film will quickly fall off with the basic coating. At this time, it is necessary to re-coat thoroughly.

Basic Coating of Joint Surface of Sheet Metal Parts

If the repaired automobile body is not rust-proof, it will be oxidized and rusted in the joint of sheet metal parts within one or two years due to the existence of various impurities and water vapor, which will affect the strength of the welding joint. Therefore, zinc flux should be sprayed in time.

Welding zinc flux (zinc-rich coating) is a new material specially used to prevent oxidation and rust on the interface of sheet metal parts. It has two kinds of dosage forms: spraying and coating. It has good electrical conductivity, high temperature resistance and electrochemical cathodic protection. It can form a layer of anti-rust protective layer between the welded joints of sheet metal parts, improve the ability of non-rust around the weld joints, protect the weld joints, and ensure that the strength of the repaired body is not inferior to that of the original body.

Foundation Coating for Shaping Welding

Although the surface of welds, solder joints and repaired steel plates has been polished and cleaned, there are still innumerable minimally invasive and irregular bumps that can not be seen by the naked eye, which are mixed with innumerable oxides, impurities, water vapor and so on. Ordinary putty or rust-proof paint has rust-proof function, but it can only prevent the invasion of external rust and play a temporary sealing role. As long as it is affected by dampness and other harsh environments, defects will soon appear. If epoxy primer is used, it can play an effective protective role.

Epoxy primer is a good rust inhibitor, which can be applied to the seam of the panel or lap joint after welding, grinding, heating and quenching shrinkage. Generally, the pinnate edge (i.e. the groove) of the paint film on the edge of the repair piece is finished, and then the epoxy primer is applied after cleaning the surface, which can ensure that the panel after various treatments will not rust for a long time, even if it is rusty, it will also prevent the expansion of the rust range.

Without special sheet metal sealing treatment and direct coating of metal sheet metal, automotive parts in the welded or overlapped joints outside the seam will be due to various sundries, such as oil, coolant, sewage erosion and vibration of high and low uneven pavement and cracking, the anti-rust sealing line of the interface is broken through, function lost. It is an inexpensive process to apply special sheet metal sealant on joints and other parts of sheet metal.

Sheet metal sealant is a non-corrosive polyurethane PU structural adhesive, which can be used for seam filling, covering, bonding and sealing, and sometimes can replace welding without damaging the paint. It has strong bonding force, high strength after curing, strong and reliable, can enhance the strength of single component and thin shell body, and can maintain the anti-erosion function of welding or lapping joints, especially in the inner and outer parts of wheel arch, chassis, reserve compartment, cockpit floor and engine compartment.

Foundation Coating in Cavity of Box Section Components

When the car body is overhauled, it will be found that the rust stains and the steel sheet thinning and penetration in the original factory's sheet metal parts in the chamber of the box-type cross-section components are caused by the neglect of internal rust prevention and the continuous expansion of rust stains. These van-type cross-section members are often the main load components of the integral body, which will have an important impact on the crashworthiness and durability of the vehicle. Therefore, it is necessary to do a good job of anti-rust treatment in the chamber of box section or bag-shaped component.

The anti-rust wax inside the body is a good assistant of the cavity protection. It has excellent permeability and can easily penetrate into all corners and joints. The automobile stamping parts have moisture resistance and drainage property. It can prevent the rusting of the cavity where the body can not be sprayed with paint, and prevent the rusting inside of the welding area of the body plate. In addition, special spraying rods and nozzles can also be used to finish the inner surface of these sheets. Ensure the quality of final maintenance.

Other Functions of Body Foundation Coating

Earthquake-proof treatment at the joint of skeleton and skin

After engine cover and luggage compartment cover are decomposed, body sealant must be added between skin and lining before closing. This will make the closed skin close to the lining, otherwise the skin will be loose, when the engine cover or the luggage compartment cover is opened or closed, there will be abnormal noise, and resonance during the driving process may also occur.

On the upper surface of the bodywork floor, the metal surfaces of the sheet metal components and welded parts must be polished and sprayed with rust-proof primer. After drying, the same type of bodywork sound-proof lining or cushion should be pasted to absorb the vibration and noise generated by vehicle movement.

For the lower surface (outside side), the exposed and repaired metal surface should be thoroughly polished and cleaned, the original paint that will fall off around should be thoroughly removed, and 1-2 layers of anti-rust primer should be sprayed. After drying, MSP sealant or similar products should be added to the joint surface and crevice, and then sprayed. Anti-rust and anti-collision primer. After such treatment, the body floor can enhance the anti-corrosion performance and reduce the impact of stone impact noise on the carriage.

As has been said before, it is impossible to produce all the parts as well as Toyota General Motors, so we just need to know where our bad parts are made. For example, Toyota's water tank is mostly made by Japan Configuration Company, and most of its electrical appliances are made by electric appliances. Most of SAIC's general lamps are manufactured by small companies. With these experiences, once insured, they can purchase the products of the corresponding parts manufacturers. There are many distributors of spare parts, whose products are all genuine. Goods, buy such products can avoid buying fake goods or high prices. If you do not know where your car parts are matched, you can consult several popular automobile forums, there are always enthusiasts to answer these questions, at least to save you a pen. If you really don't know, you can call the local fittings supplier, give a good fare, you can give the corresponding number of your car parts, universal network, generally speaking, according to the convenient number to buy very few mistakes (each car has a unique 17VIN, that is, identity card, so that sales check corresponding VIN can show that Find out the coding of the parts.