Automotive Industry Standard of the People's Republic of China
QC/T 268—1999
Replace ZB T04 006.3—89
Automotive Cold Stamping Part
Limit Deviation of without Indicating Tolerance Size
1 Main content and applicable scope
This standard specifies the limit deviation of size factor which is not marked tolerance formed by cold
stamping in the automotive parts diagram.
The Standard is suitable for the limit deviation of size factor which is not marked tolerance formed by
cold stamping in the automotive parts diagram.
2 Terms
Cutting Size: the size measured at the bright part of blanking.
3 Limit deviation of without indicating tolerance size of Flat stamping process
3.1The limit deviation of without indicating tolerance size of flat stamping part's length L, diameter D, d
should be according to the regulation of Figure 1, Table 1.
Figure 1
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QC-T 268-1999
Table 1
mm
thickness ≤3 ＞3～10 ＞10
limit deviation
Basic size Neither Neither
Neither hole
hole axle hole nor hole axle hole axle hole nor
nor axle
axle axle
+0.14 0
≤3 ±0.07
0 -0.14
+0.18 0
＞3～6 ±0.09
0 -0.18
+0.22 0 +0.36 0
＞6～10 ±0.11 ±0.18
0 -0.22 0 -0.36
+0.27 0 +0.43 0
＞10～18 ±0.14 ±0.22
0 -0.27 0 -0.43
+0.33 0 +0.52 0 +0.84 0
＞18～30 ±0.17 ±0.26 ±0.42
0 -0.33 0 -0.52 0 -0.84
+0.39 0 +0.62 0 +1.00 0
＞30～50 ±0.20 ±0.31 ±0.50
0 -0.39 0 -0.62 0 -1.00
+0.46 0 +0.74 0 +1.20 0
＞50～80 ±0.23 ±0.37 ±0.60
0 -0.46 0 -0.74 0 -1.20
+0.54 0 +0.87 0 +1.40 0
＞80～120 ±0.27 ±0.44 ±0.70
0 -0.54 0 -0.87 0 -1.40
+0.63 0 +1.00 0 +1.60 0
＞120～180 ±0.32 ±0.50 ±0.80
0 -0.63 0 -1.00 0 -1.60
+0.72 0 +1.15 0 +1.85 0
＞180～250 ±0.36 ±0.58 ±0.93
0 -0.72 0 -1.15 0 -1.85
+0.81 0 +1.30 0 +2.10 0
＞250～315 ±0.41 ±0.65 ±1.05
0 -0.81 0 -1.30 0 -2.10
+0.89 0 +1.40 0 +2.30 0
＞315～400 ±0.45 ±0.70 ±1.15
0 -0.89 0 -1.40 0 -2.30
+0.97 0 +1.55 0 +2.50 0
＞400～500 ±0.49 ±0.78 ±1.25
0 -0.97 0 -1.55 0 -2.50
+1.10 0 +1.75 0 +2.80 0
＞500 ±0.55 ±0.88 ±1.40
0 -1.10 0 -1.75 0 -2.80
Note: Table 1 also applies to the stamping forming process of the flat planar blanking size, shown in
Figure 1, C plan.
3.2 The limit deviation of without indicating tolerance size of cutting Arc part's radius r should
be according to Table 2.
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QC-T 268-1999
Table 2
mm
thickness ≤1 ＞1～3 ＞3～6 ＞6～10 ＞10
Basic size limit deviation
≤6 ±0.20 ±0.30 ±0.40 - -
>6~18 ±0.40 ±0.50 ±0.50 ±0.60 -
>18~50 ±0.50 ±0.60 ±0.70 ±0.80 ±1.00
>50~160 ±0.60 ±0.70 ±0.90 ±1.10 ±1.30
>160~400 ±0.80 ±1.00 ±1.20 ±1.60 ±2.00
>400 ±1.40 ±1.00 ±1.80 ±2.00 ±2.80
3.3 When blanking pattern is not specified the value of the internal and external angular radius r (Figure 1)
formed by two blanking sides, r should be less than 70% of the nominal material thickness.
3.4 The limit deviation of without indicating tolerance size of cutting angle part’s radius r should be
according to Figure 2, Table 3.
Figure 2
NOTE: Without giving the virtual edges size of the short Constituted angle side, determine by the actual
existence of side length L
Table 3
angle , length of the short edge ≤6 ＞6～18 ＞18～50 ＞50～180 ＞180～400 ＞400
L，mm
the limit deviation of angle ±1°30′ ±1° ±0°50′ ±0°25′ ±0°10′ ±0°10′
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QC-T 268-1999
4 The tolerance of curved pieces forming part
4.1 The limit deviation of without indicating tolerance size of bending length L, crimping diameter d should be
according to Figure 3, Table 4 provides.
Figure 3
Table 4
mm
Basic size maximum outline size of bending section
≤6 ＞6～30 ＞30
＞ to
limit deviation
6 ±0.8 - -
6 18 ±1.1 - -
18 50 ±1.6 ±1.2 -
50 120 ±2.2 ±1.5 ±1
120 250 ±3 ±2 ±1.2
250 500 ±4 ±2.5 ±1.5
500 800 ±5 ±3 ±2
800 1250 ±6 ±4 ±2.5
1250 2000 ±7 ±5 ±3
4.2 Allow the external diameter of pipe bend deformation, deformation (maximum diameter and minimum
diameter difference) is provided by Table 5.
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QC-T 268-1999
Table 5 mm
outside diameter size of tube ≤10 ＞10～18 ＞18～30 ＞30
outside diameter Deformation 1.8 2.5 3.5 5.0
Note: When the pipe union nuts and other parts are assembled, the deformed dimensions should ensure its
smooth passage of the bend.
4.3 The tolerance of size factor which size is not marked tolerance of bending angle should be according to
Figure 4, Table 6 provides.
Figure 4
Table 6
angle , length of the short edge
≤30 ＞30～50 ＞50～80 ＞50～120 ＞120
mm
thickness≤2mm ±1°30′ ±1°15′ ±1° ±0°45′ ±0°38′
the tolerance of
thickness＞
angle ±1°15′ ±1° ±0°45′ ±0°38′ ±0°30′
2mm
5 The tolerance of size factor which size is not marked tolerance of shape drawing
5.1 The tolerance of size factor which size is not marked tolerance of drawing diameter d1 enlarge one grade
should be according to Table 1 provides.
5.2 The tolerance of size factor which size is not marked tolerance of drawing part depth H enlarge one grade
should be according to Figure 5, Table 7 provides.
Figure 5
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QC-T 268-1999
Table 7 mm
Drawing depth
material
≤18 ＞18～50 ＞50～120 ＞120～180 ＞180～250 ＞250～500
thickness
Limit deviation
≤1 ±0.3 ±0.5 ±0.8 ±1.0 ±1.4 ±1.6
＞1～2 ±0.4 ±0.6 ±1.0 ±1.2 ±1.6 ±1.8
＞2～4 ±0.5 ±0.8 ±1.2 ±1.4 ±1.8 ±2.0
＞4～6 ±0.6 ±1.0 ±1.4 ±1.6 ±2.0 -
5.3 The tolerance of size factor which size is not marked tolerance of ribs, enhance nest height h should be
according to Figure 6, Table 8 provides.
Figure 6
Table 8 mm
height h ≤3 ＞3～6 ＞6～10 ＞10～18 ＞18～30 ＞30
tolerance +0.8 +1.0 +1.2 +1.5 +2.5 +3.0
-0.3 -0.5 -1.0 -1.0 -1.0 -1.0
5.4 The tolerance of size factor which size is not marked tolerance of molding radius r (Figure 3, Figure 5,
Figure 6) should be according to Table 9.
Table 9
mm
Arc radius ≤3 ＞3～6 ＞6～10 ＞10～18 ＞18～30 ＞30
tolerance +1 +1.5 +2.5 +3 +4 +5
0 0 0 0 0 0
Note: If the pattern is not specified the value of radius r, r should not be greater than the nominal material
thickness.
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QC-T 268-1999
5.5 Drawing parts forming material allowed local thinning or thickening, the minimum thickness after
thinning:
tmin=0.8tnormal-△
Where：tmin—— the minimum material thickness,mm,
tnormal——normal material thickness,mm,
△——the absolute value of material thickness deviation,mm.
6 The tolerance of size factor which size is not marked tolerance of the hole margins, hole center
distance and the distance of holes of stamping parts
6.1 The tolerance of size factor which size is not marked tolerance of distance between profiles punching such
as tape material, flat strips to the edge should be according to Figure 7, Table 10.
Figure 7
Table 10
mm
Basic size maximum length of part
C ≤300 ＞300～600 ＞600
Limit deviation
≤50 ±0.5 ±0.8 ±1.2
＞50 ±0.8 ±1.2 ±2.0
6.2 The tolerance of size factor which size is not marked tolerance of groups hole center distance connecting
with the same parts should be according to Figure 8, Table 11.
Figure 8
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QC-T 268-1999
Table 11 mm
groups hole ≤18 ＞18～120 ＞120～250 ＞250～500 ＞500
center distance
tolerance ±0.20 ±0.25 ±0.30 ±0.50 ±0.60
6.3 The tolerance of size factor which size is not marked tolerance of holes spacing connecting with different
parts should be according to Figure 9, Table 12.
Figure 9
Table 12
holes spacing L ≤120 ＞120～250 ＞250～500 ＞500～1200 ＞1200
tolerance ±0.6 ±0.8 ±1.2 ±1.6 ±2.0
6.4 The tolerance of size factor which size is not marked tolerance of holes spacing affected by the warping
should be according to Figure 10, Table 13.
Figure 10
Table 13 mm
Basic size L the maximum profile size of Curved section a
≤2 ＞2～6 ＞6
1）
hole diameter D
＞ to ≤6 ＞6 ≤6 ＞6
2）
tolerance
120 ±0.3 ±0.4 ±0.2 ±0.3 ±0.2
120 500 ±0.5 ±0.6 ±0.4 ±0.5 ±0.3
500 ±0.8 ±1.0 ±0.6 ±0.8 ±0.5
Note: 1) Determined by the arithmetic means diameter for whole distance limit deviation of different
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QC-T 268-1999
diameter hole.
2) Processing of parts in the normal process, if the deviation caused by elastic warping is more
than the deviation of Table 13, as long as it can guarantee parts assembly, it is still permitted.
Additional Note:
The standard is proposed by the State Administration of Machinery Industry.
This standard is under the jurisdiction of the National Automotive Standardization Technical Committee.
Drafting of this standard: China Automotive Technology and Research Centre organized a joint working
group.
Main drafters of this standard: Liu Li, Xi Zhu whole.
