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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 708-2006 Dimension, shape, weight and tolerance for cold-rolled steel strip and sheet.
In addition to editorial changes, the following technical changes have been made with respect to GB/T 708-2006:
——the thickness and width dimension range of steel sheet and steel strip are modified (see Sub-clause 5.1, Sub-clause 5.1 in Edition 2006);
——the thickness tolerances of steel sheet and steel strip are modified, they are respectively determined according to specified minimum yield strength Re < 260 MPa, 260 MPa ≤ Re <340 MPa, ≤, 340 MPa ≤ Re ≤420 MPa, Re > 420 Mpa (See Table 2, Table 3, Table 4, Table 5, Table 2 in Edition 2006);
——the higher precision (PW.B) and requirements of width tolerances of slit wide strip are added, and the width tolerances of slit wide strip is modified (see Sub-clause 6.2.3, Sub-clause 6.2.2 in Edition 2006) ;
——the flatness of steel sheet and steel strip is modified, the Re < 260 MPa and 260 MPa ≤ Re < 340 MPa are divided according to the specified minimum yield strength Re < 280 MPa and 280 MPa ≤ Re <360 MPa, and the flatness requirements are modified (see Sub-clause 7.1, Sub-clause 7.1 in Edition 2006);
——the requirements for supply of thickness tolerance, width tolerance, length tolerance of steel sheet and steel strip and flatness supply based on the ordinary precision under default state are added (see Sub-clauses 6.1.6, 6.2.2, 6.3 and 7.1.1);
——the negotiation terms of the thickness tolerance and flatness requirements are added when the yield strength and requirements are not specified in the product specification (see Sub-clauses 6.1.5 and 7.1.5);
——the requirement on camber is modified (see Sub-clause 7.2; Sub-clause 7.2 in Edition 2006);
——the "beveling" is modified to "out-of-square", and methods and requirements for measuring out-of-square with diagonal method are added (see Sub-clause 7.3; Sub-clause 7.3 in Edition 2006);
——the requirements on measurement position of steel strip flatness are added (see Sub-clause 8.3.3);
——the schematic diagram for measuring the out-of-square with diagonal method is added [(see Sub-clause 8.5b)].
This standard was proposed by the China Iron and Steel Association.
This standard is under the jurisdiction of SAC/TC 183 National Technical Committee on Iron and Steel of Standardization Administration of China.
The previous editions of the standard replaced by this standard are as follows:
——GB/T 708-1965, GB/T 708-1988 and GB/T 708-2006.
Dimension, shape, weight and tolerance for cold-rolled steel strip and sheet
1 Scope
This standard specifies the terms and definitions, classification and code, dimension, dimensional tolerance, shape requirements, dimension and shape measurement, weight and numerical rounding of cold-rolled steel sheets and strips.
This standard is applicable to cold-rolled wide strip with a rolled width of not less than 600 mm, slit wide strip and sheet cut from strip (hereinafter referred to as steel sheets and steel strips). A single cold-rolled steel sheet can also be carried out as above.
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 of the normative document (including any amendments) applies.
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
wide strip
steel strip with a rolled width of not less than 600 mm and delivered in rolls
3.2
slit wide strip
formed by slit wide of wide strip and delivered in rolls
3.3
sheet cut from strip
formed by cutting from strip and delivered in shapes
3.4
plate
cold-rolled flat steel with directly rolled and not fixed edge deformation
4 Classification and code
4.1 The classification and code are as follows based on the edge state:
a) edge-cut, EC;
b) edge-mill, EM;
4.2 The classification and code are as follows based on the dimension precision:
a) ordinary thickness precision, PT.A;
b) higher thickness precision, PT.B;
c) ordinary width precision, PW.A;
d) higher width precision, PW.B;
e) ordinary length precision, PL.A;
f) higher length precision, PL.B.
4.3 The classification and code are as follows based on the flatness precision:
a) ordinary flatness precision, PF.A;
d) higher flatness precision, PF.B.
4.4 The classification of dimension and flatness corresponding to product modality and edge state is shown in Table 1.
Table 1 Classification of dimension and flatness corresponding to product modality and edge state
Product modality Classification and code
Edge state Thickness precision Width precision Length precision Flatness precision
Ordinary Higher Ordinary Higher Ordinary Higher Ordinary Higher
Wide strip Edge-mill EM PT.A PT.B — — — — — —
Edge-cut EC PT.A PT.B PW.A PW.B — — — —
Steel sheet Edge-mill EM PT.A PT.B — — PL.A PL.B PF.A PF.B
Edge-cut EC PT.A PT.B PW.A PW.B PL.A PL.B PF.A PF.B
Slit wide strip Edge-cut EC PT.A PT.B PW.A PW.B — — — —
5 Dimension
5.1 Dimension range
5.1.1 The nominal thickness of steel sheets and strips is not greater than 4.00 mm.
5.1.2 The nominal width of steel sheets and strips is not greater than 2150 mm.
5.1.3 The nominal width of steel sheets is 1000 mm~6000 mm.
5.2 Recommended nominal dimension
5.2.1 The nominal thickness of steel sheets and strips is within the range specified in Sub-clause 5.1, the recommended nominal thickness of the steel sheets and strips with nominal thickness of 1.00 mm is any dimensions with a multiple of 0.05 mm; the recommended nominal thickness of the steel sheets and strips with nominal thickness of 1.00 mm is any dimensions with a multiple of 0.01 mm.
5.2.2 The recommended nominal width of steel sheets and strips is any dimensions with a multiple of 10 mm.
5.2.3 The nominal length of steel sheets is within the range specified in Sub-clause 5.1. The recommended nominal length is any dimensions with a multiple of 50 mm.
5.2.4 As required by the demander, the steel sheets and strips with other dimensions can be supplied upon negotiation between the supplier and demander.
6 Dimension tolerance
6.1 Thickness tolerance
6.1.1 The thickness tolerance of steel sheets and strips with minimum yield strength Re of less than 260 MPa shall meet those specified in Table 2.
6.1.2 The thickness tolerance of steel sheets and strips with minimum yield strength Re of 260 MPa~<340 MPa shall meet those specified in Table 3.
6.1.3 The thickness tolerance of steel sheets and strips with minimum yield strength Re of 340 MPa~420 MPa shall meet those specified in Table 4.
6.1.4 The thickness tolerance of steel sheets and strips with minimum yield strength Re of greater than 420 MPa shall meet those specified in Table 5.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification and code
5 Dimension
6 Dimension tolerance
7 Shape
8 Measurement of dimension and shape
9 Weight
10 Rounding of numerical values
