Chery QQ6 (S21) / S12LHD. Manual - part 150

惯性锤

手柄

平垫片

惯性锤

手柄

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

Handle

Flat gasket

Slide hammer

Handle

伸胀区

点状加热

伸胀区

边缘呈波浪状

加热位置

三角形加热

图 11

（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.
Steps 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.

（4） Select proper processing and shaping methods so that the patch matches well with the

Stretched area

Spot heating

Waved edge

Stretched area

Heated spots

Triangle heating

part to be removed.

（5） Apply the patch to the intended position and press it tightly, draw a line along the edge

of the part to be removed and cut it out, using methods like gas cutting or excising
according to the actual situation, and then align the patch with the excised area.

（6） Weld the seam by gas welding or carbon oxide protection welding. Spot-weld it at a

pace  of  30-50mm  to  fix  it  and  then  weld  it  again  in  a  certain  order  after  beating  it
smooth.  For  seams  requiring  welding  of  higher  strength,  doulble-sided  welding  is
prefered.

（7） Smooth the welded seam by beating it with flat hammer, release the welding pressures,

and then shape it and polish the seam with a grinding machine.

4.4. Restoration of Wrinkled Parts

Depending  on  the  damage  extent  of  the  plate  work  pieces,  the  wrinkles  are  divided  into  “live
wrinkles” and “dead wrinkles”. The “live wrinkles” are slight ones and can be directly removed by
beating  the  convex  part  with  a  hammer.  The  “dead  wrinkles”  refere  to  seriously  damaged  parts.
Since  the  wrinkles  are  folded  and  pressed  against  each  other,  so  if  you  hammer  the  most  convex
part,  the  wrinkles  would  get  even  more  seriously  and  harder  to  release,  hence  the  name  “dead
wrinkles”.  The  principle  of  correcting  the  wrinkles  is  to  spread  “dead  wrinkles”  first  so  that  they
become  “live  wrinkles”,  and  then  “live  wrinkles”  are  converted  into  convex-concave  shape,  and
finally  restore  the  damaged  parts  just  as  you  deal  with  convex-concave  damages.  The  repairing
steps are as follows:

（1） First use support-draw method to apply a correcting force in the direction opposite to

that of the impact at the wrinkled part of the plate work, and then spread and ease the
wrinkles.

（2） Remove the wrinkled plate work and lay it on a platform and then, beginning with

the inner side of the wrinkled area, pry up the wrinkles with a proper prying tool and
heat the “dead wrinkles” one by one with a welding torch at the same time. Finally
all “dead wrinkles” are pried up and eased and converted into“live wrinkle”.

（3） Beat and smooth the “live wrinkles” from the inner side outward. The hammered

spots should be near the most convex part of the “live wrinkles”. At the same time
make sure the platform can support every beaten spot. When the wrinkles in one side
of the plate are almost smoothed, turn it over to beat the other side till all wrinkles are
completely spread out.

（4） Measure with a templet, and at the same time heat and beat the convex-concave part

to restore it to its original shape.

（5） When the vehicle body is assembled, test with a templet again and make finer

correction to achieve the final requirements.

（6） The seriously damaged wrinkles that can not be restored can be excised and repaired.

4.5. Welding of Four Doors and Two Covers

When welding the door panel, choose proper welding methods: gas welding (oxygen and

acetylene welding), CO

shielded welding, manual arc welding, resistance spot welding, braze

welding and so on. Besides, in order not to reduce the original strength and durability of the vehicle
body, try to adopt the welding methods used in manufacturing the door panels, and the dimensions
and types of all weld joints should be similar to those used by the original manufacturer.

As for appearance and quality, no burnt-through spots, half points, cracks, a lot of burrs or

other defects should exist at the welded parts. The welded surface should be smooth and
nice-looking, no obvious twist or deformation is allowed, and the indentation depth should be less
than 1/5 of the plate thickness. Flat spade and iron hammer can be used to carry out non-destructive
tests of the welded spots’ strength. Insert the flat spade between two welded spots to see if they are

easy to separate, and then beat the welded part with an iron hammer to restore it. No welding spatter
is allowed at the welded seam, and the overlapped seam should be nice-looking with no defects like
air holes or cracks. Defects like undercut, welding beading and burning through are also not
allowed.

II. Vehicle Body Assembly Dimensions

1. Front View

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