GB/T 709-1988 covers the dimensions, shape and tolerances of hot-rolled steel plate, sheet and strip produced by the hot-rolling process.
1 Scope
This standard applies to hot-rolled flat steel products for direct cold forming (gee section 1.1.1).
It specifies the dimensions and shape, permissible sizes and tolerances, and so on.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding corrections to), or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 222-1984, Permissible tolerances for chemical composition of steel products.
3 Definition and classification
3.1 Definition
Hot-rolled flat steel products are those of a rectangular plate, of which of the width/thickness ratio is greater than 2.
Unless otherwise specified, the width/thickness ratio is taken as 3 to 1 or more.
3.2 Classification
Hot-rolled flat steel products are classified as follows according to strip or plate shape:
Sheet (e.g. coils, strips and other flat metal products of which the width-to-thickness ratio is less than 2);
Plate (e.g. of which the width-to-thickness ratio is more than 2);
4 Dimensions and weight
4.1 The dimensions of hot-rolled flat steel products are expressed as follows:
4.1.1 Thickness
The thickness of hot-rolled flat steel products are expressed in millimeters.
4.1.2 Width
The width of hot-rolled flat steel products are expressed in millimeters.
4.1.3 Length
The length of hot-rolled flat steel products are expressed in meters.
4.2 Weight
The weight of hot-rolled flat steel products are expressed in kilograms.
5 Permissible sizes
5.1 Sheet
Table 1. Permissible sizes for sheet
Thickness (mm) Width (mm) 0.35-1.50 ≤ 1250 > 1250-1550 1550-2000 > 2000-2500 0.25-0.50 － － 0.51-0.80 − － 0.81-1.00 − － > 1.00-1.50 − −
5.2 Plate
Table 2 Permissible sizes for plate
Thickness (mm) Width (mm) Length (m) 4.50-15.00 ≤ 1250 3.00 > 1250-1800 2.75 > 1800-2400 2.50 > 2400-3000 2.25 > 3000-3200 2.00 > 3200-4000 1.75 > 4000-5000 1.50
6 Shapes and tolerances
Table 3 Permissible shape and tolerances
Shape Permissible tolerances Sheet or plate Thickness tolerances Width range tolerance Length range tolerance Sheet 0 ～ +0.30 0 ～ 2.0 0 ～ 2.0 Plate 0 ～ +0.40 0 ～ 3.0 0 ～ 3.0
7 Marking
The manufacturer shall mark the hot-rolled flat steel products as required by GB/T 6388 (Export product marking).
8 Inspection
The hot-rolled flat steel products shall be inspected in accordance with GB/T 6730.
9 Packaging
The hot-rolled flat steel products shall be packaged in accordance with GB/T 4257.
10 Storage
The hot-rolled flat steel products shall be stored in accordance with GB/T 4257.
