Restoration Of Stretched Parts - Chery A113 Maintenance Manual

Puncturing: Drill a small hole in the dent with a hand power drill, and then insert a pull-rod
with threaded head or hook-shaped head into the hole. Slide the slide hammer on the metal pull-rod
and impact the handle repeatedly so as to pull up the dent gradually. Make more than one holes
when necessary, and fill the hole(s) by soldering and polish the spot(s) when the dent(s) is/are
smoothed.
Electrode welding: Weld a peg or a flat gasket onto the dent with a special spot-welder, and
then use a dent smoother to pull at the peg or flat gasket till the dent is smoothed. More than one
peg or flat gaskets can be welded when necessary so that the whole dented area can be dragged out.
Finally, break the peg or flat gasket, and polish the welded scar with a sand mill. This method can
avoid drilling the metal panels and prevent potential erosion, so it is widely used.

4.2. Restoration of Stretched Parts

When the metal panel is impacted, the dented area would be stretched. At times even proper
operations can not restore it, the heating-contracting method is sometimes used to achieve the
desired repairing effect.
(2) 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.
Slide hammer
惯 性 锤
Handle
Slide hammer
Flat gasket
平 垫 片
手 柄
87
惯 性 锤
Handle
手 柄