Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative
This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for standardization — Part 1: Rules for the structure and drafting of standardizing documents.
This document replaces GB/T 15055-2007 Permissible stamping variations in dimensions without tolerance indication. In addition to structural adjustment and editorial changes, the following main technical changes have been made with respect to GB/T 15055-2007:
a) The sentence "this standard may be used as a reference for precision stamping and extrusion parts" has been deleted (see Clause 1 in 2007 edition);
b) Symbols in the figures have been added (see Clause 3 herein);
c) The definition of "blanking size" has been modified, and a schematic diagram of blanking size has been added (see 3.1 herein and 2.1 in 2007 edition);
d) The definition of "blanking corner radius" has been modified (see 3.3 herein and 2.3 in 2007 edition);
e) The definition of "bending angle" has been modified (see 3.6 herein and 2.6 in 2007 edition);
f) "angles without tolerance indication" has been modified as "blanking angle without tolerance indication and bending angle without tolerance indication" (see Clause 4 herein and Clause 3 in 2007 edition);
g) The explanations of the four symbols "f", "m", "c" and "v" have been deleted and "Tolerances shall be indicated for dimensions of 0.5 mm and below" has been added (see Clause 4 herein and Clause 3 in 2007 edition);
h) The names of the relevant dimensions have been modified, and the titles of Tables 1, 2, 3 and 4 have also been modified accordingly (see Clauses 5 and 6 herein and Clauses 4 and 5 in 2007 edition);
i) The units of angles in Tables 5 and 6 have been modified, and "Length of short side" in Table 6 has been modified to "Minimum dimension of straight edge of bending part" (see Clause 6 herein and Clause 5 in 2007 edition).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This document was proposed by and is under the jurisdiction of the National Technical Committee on Metalforming Machinery of Standardization Administration of China (SAC/TC 74).
The previous editions of this document are as follows:
——It was first issued as GB/T 15055-1994 in 1994, and first revised in 2007;
——This is the second revision.
Permissible stamping variations in dimensions without tolerance indication
1 Scope
This document specifies the stamping tolerance grades and permissible variations of linear and angular dimensions without individual tolerance indications.
This document is applicable to metal stampings, and may apply to non-metal stampings by reference.
The permissible variations specified in this document applies to non-fit dimensions.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 8541 Terminology of forging and stamping
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 8541 and the following apply.
3.1
blanking size
linear dimension of the stamping processed by blanking, punching and other separation processes (see D, d, s1 and s2 in Figure 1)
mm
a) Circular blanking part b) Rectangular blanking part
Keys:
D——the outside diameter of circular blanking part;
d——the punching aperture;
s1——the length of rectangular blanking part;
s2——the width of rectangular blanking part;
t——the thickness of sheet material.
Figure 1 Blanking size
3.2
forming size
linear dimension of the stamping processed by bending, drawing and other forming processes (see l1, l2, d1, h and h1 in Figures 2 and 3)
Keys:
l1——the minimum dimension of straight edge of the bending part, mm;
l2——the maximum dimension of straight edge of the bending part, mm;
r——the corner radius of inside bending, mm;
β——the angle of bending, °.
Figure 2 Linear and angular dimensions of bending part
mm
a) Cylindrical drawing part b) Rectangular drawing part
Keys:
Df——the flange diameter;
d1——the diameter of inner cavity of drawing part;
h——the height of cylindrical drawing part;
h1——the height of rectangular drawing part;
r1——the corner radius between bottom and straight wall;
r2——the corner radius between flange and straight wall;
r3——the corner radius between two straight walls.
Figure 3 Linear dimensions of drawing part
3.3
blanking corner radius
linear dimension of the corner radius of stamping processed by blanking, punching and other separation processes (see R in Figure 4)
a) Punching part b) Blanking part
Keys:
R——the blanking corner radius, mm;
α——the blanking angle, °.
Figure 4 Blanking corner radius and blanking angle
3.4
forming corner radius
linear dimension of the corner radius of stamping processed by bending, drawing and other forming processes (see r, r1, r2 and r3 in Figures 2 and 3)
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Tolerance grade
5 Permissible variation in dimensions without tolerance indication
6 Representation method of non-indicated tolerance grade
