QC/T 268-2023Permissible automobile cold stamping variations in dimensions without tolerance indication (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020

"Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents".

This document replaces QC/T 268-1999 "Extreme deviation for undeclared tolerance

size of processing parts for automobile cold stamping". Compared with QC/T 268-1999,

in addition to structural adjustments and editorial modifications, the main technical

changes are as follows.

a) ADD normative references (see Chapter 2);

b) DELETE the terms and definitions of "punching dimensions", directly quoting

the terms and definitions defined in GB/T 15055 (see Chapter 3; Chapter 2 of the

1999 edition);

c) DELETE the limit deviation provisions of holes and shafts without dimension

indications in Table 1; CHANGE "basic dimensions" to "nominal dimensions",

adding the tolerance grading (see 4.1; Table 1 of the 1999 edition);

d) CHANGE the "punching angle without tolerance indication" to "punching angle

without tolerance indication" (see 4.2; 3.4 of the 1999 edition);

e) CHANGE some values of the angle limit deviation in Table 3 (see 4.2.2; Table 3

of the 1999 edition);

f) CHANGE the "bending angle without tolerance indication" to "bending angle

without tolerance dimension indication" (see 5.2; 4.3 of the 1999 edition);

g) CHANGE the key "angle short side length mm" in Table 6 to "angle short side

length L/mm" (see 5.2.2; Table 6 of the 1999 edition);

h) ADD the grading for the limit deviation of the hole spacing without tolerance

indications affected by warpage (see 7.4.2);

i) CHANGE "T minimum" to "Tmin"; CHANGE "T nominal" to "T" (see 6.5; 5.5 of the

1999 edition).

Please note that some contents of this document may involve patents. The issuing

agency of this document does not assume the responsibility of identifying patents.

This document was proposed by AND shall be under the jurisdiction of the National

Automobile Standardization Technical Committee (SAC/TC 114).

Drafting organizations of this document. Dongfeng Motor Group Co., Ltd., Pan Asia

Automotive Technology Center Co., Ltd., Beijing Automotive Off-road Vehicle

Research Institute Co., Ltd.

1 Scope

This document specifies the permissible automobile cold stamping variations in

dimensions without tolerance indication in the drawings of automotive product parts.

This document is applicable to the permissible automobile cold stamping variations in

dimensions without tolerance indication in the drawings of automotive product parts.

2 Normative references

The contents of the following documents constitute the essential provisions of this

document through normative references in the text. Among them, for dated references,

only the version corresponding to that date applies to this document; for undated

references, the latest version (including all amendments) applies to this document.

GB/T 15055 Permissible stamping variations in dimensions without tolerance

indication

3 Terms and definitions

The terms and definitions defined in GB/T 15055 apply to this document.

4 Limit deviations of dimensions without tolerance

indications for flat stamping

5 Dimensional tolerance of formed bent parts

6 Limit deviation of forming and drawing without tolerance indications

8 The method of expression in this document

The limit deviation of the dimension without tolerance indication specified in this

document shall be expressed by the document number and tolerance grade symbol in

the corresponding drawings, technical documents or standards.

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