373II. Repair of Body Outer Plate1. Types Of Outer Plate Damage
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1Break or crackle
The body always vibrates as the vehicle runs; and it bears an alternating load. When the vehicle suddenly
accelerates, sharply turns and emergently brakes, the body will be affected by inertia force. When the
vehicle runs on a rough road, the body will get bent and deformed by torsion.
If the vehicle experiences this kind of outside force in a long term, the outer plate of the body will get
broken and cracked on the parts that stress concentrates and the structure is weak.
It is easy for the stress to concentrate at the turning, edging and narrow places of the body outer plate, for
example, it is easy for the 4 corners of the slide door sash to get broken and cracked.
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2 Corrosion
The corrosion of the body outer plate is mostly caused by mud accumulated on the surface of the metal,
which results in rust. Only in some special situations, it is caused by contacting chemical materials, which
belongs to chemical corrosion. When the metal outer plate corrodes, the rust is generated on the outer
plate, and then peels off layer by layer, so that holes appear and become bigger and bigger. Rust is easily
generated on the outer plate of the skirt, drip channel, and at the joints of doors and sashes, and at the
interlayer formed by outer plate and frame jointing places.
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3Recess
Recess is a kind of structural damage, caused by crash or squeezing on the outer plate of the body. As to
slight recess, the metal dose not extend. It belongs to plastic deformation. When it is seriously impacted
and squeezed, the metal outer plate will be torn. For the vehicles running on city, side wall outter plates
being crashed and scratched is common.
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4Bending and torsion
Beading and torsion deformation belongs to mechanic damage. Many causes result in this kind of situation,
such as body being crashed or squeezed, an alternating load in vibrating as the vehicle runs, sudden
acceleration, emergent brake, sharp turn and running through a bad pavement, etc. Those can all result in
bending and torsion deformation on body outer plate.
Slight deformation should be confirmed by inspection. For serious bending and torsion deformation, they
can be easily found by appearance. The deformation information can be usually defined according to the
clearance between door frame and their relative position changes.
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5Breakup Welding
Outer plate being breakup welding is caused by bad welding between metal plates.
