Chery S18D Service Manual
repairing effect.
(1) Heated position and flame intensity: The effect of flame correction depends on the heated position
and the flame intensity. Different heated spots bring about different effects, and the heated position
should be where the material is deformed the most and the metal panel is stretch the most, or the
furthest part outward that is bent and deformed. Different flame intensities also lead to different
correcting effects. The intenser the flame is, the faster the metal panel is heated and the more
concentrated the heat is, and then the stronger the contracting capability is. The low-carbon steel
panel, for example, should be heated till it gets cherry red (600
- 800
℃
℃
).
(2) Heating ways normally adopted for flame correction in the vehicle body maintenance are:
①
Spot heating: The heated area is a round spot of a certain diameter, which is usually 15 -
30mm. One or more spots can be heated according to the actual deformity situation. When
more than one spot is heated, the spots are arranged in a plum pattern. And this way is often
used for contracting the convex area in the middle of the panel.
②
Triangle heating: The heated area resembles a triangle, and this way is often used for
correcting strip-shaped materials and deformed panel edges.
·
Expansion
area
Wavy edge
Heating position
Triangle heatin
Fig. 11
Stretched
area
Spot heating
Fig. 1 0
(3) Cooling-contracting way: When the flame is taken away, proper cooling ways should be chosen
according to the stretched degrees of the metal panels. Different cooling ways bring about different
contracting effects.
①
Natural cooling-contracting, or cooling in the air naturally, which is suitable for smaller areas of
deformities.
②
Water cooling, or covering the heated area with wet cotton cloth to make it cool suddenly. The
contraction of metal plate cooled in this way is larger than that of the naturally cooled one, but
it may make the steel panel fragile.
③
Natural cooling and hammering, usually operated with a hand hammer and a underlay iron.
During the operation, beat around the heated area quickly to increase the compressing stress
and the contraction till that area is smoothed. The wooden hammer is preferred and do not use
too strong a force, or the metal panel may get re-stretched.
4.3. Restoration of Cutting & Patching
When any part of the metal door panel is eroded or damaged beyond repair, it should be removed and
replaced with a new piece by welding. The repairing methods include patching repair and cutting.
Procedures for cutting repair are as follows:
(1) Check the damaged part and determine the repairing area.
(2) Make a paper model according to the determined area.
(3) Draw lines on the metal plates and cut material according to the paper model, and leave proper
processing allowance.
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