GB/T 25052-2024Dimensions, shape, weight and tolerances for continuously hot-dip coated steel sheet and strip (English PDF)

3.1 Wide strip

Steel strip with a rolling width of not less than 600 mm and delivered in coils.

3.2 Slit wide strip

Steel strip cut longitudinally from a wide strip (3.1) and delivered in coils.

3.3 Nominal(specified) thickness

Ordering thickness of coated products.

5.1 Dimension range

5.1.1 The nominal thickness of wide strips, steel sheets and slit wide strips shall not exceed 6.50 mm.

5.2 Recommended nominal dimensions

5.2.1 The nominal thickness of wide strips, steel sheets and slit wide strips is within the range specified in 5.1.

5.2.2 The nominal width of wide strips, steel sheets and slit wide strips shall be any dimension in multiples of 10 mm.

6.1 Tolerance on thickness

6.1.1 The tolerances on thicknesses of wide strips, steel sheets and slit wide strips with the specified minimum yield strength of less than 260 MPa shall comply with the provisions of Table 2.

6.1.2 The tolerances on thickness of wide strips, steel sheets and slit wide strips with the specified minimum yield strength not less than 260 MPa and less than 360 MPa shall comply with the provisions of Table 3.

6.1.3 The tolerances on thickness of wide strips, steel sheets and slit wide strips with the specified minimum yield strength of not less than 360 MPa and less than or equal to 420 MPa shall comply with the provisions of Table 4.

6.1.5 When the yield strength and tolerance on thickness are not specified in the document specifying the product requirements, the tolerances on thickness of wide strips, steel sheets and slit wide strips shall be negotiated by the supplier and the buyer and shall be indicated in the contract.

6.2 Tolerance on width

6.2.1 The tolerances on widths of wide strips and steel sheets with cut edges shall comply with the provisions of Table 6. The tolerances on widths of steel sheets and wide strips with mill edges shall be determined by negotiation between the supplier and the buyer.

6.2.3 If the buyer requires delivery with a high precision width (PW.B), this shall be specified in the contract. If not specified, delivery will be based on the common precision width (PW.A).

6.3 Tolerance on length

The tolerances on lengths of steel sheets shall comply with the provisions of Table 8.

7.1 Flatness tolerance

7.1.1 The flatness tolerances of steel sheets shall comply with the provisions of Table 9. If the buyer requires the supply of high precision flatness (PF.B), it shall be indicated in the contract. If not indicated, the supply shall be based on the common precision flatness (PF.A).

7.1.2 When the yield strength and the flatness tolerance are not specified in the document specifying the product requirements, the flatness tolerance of the steel sheet shall be determined by negotiation between the supplier and the buyer and shall be stated in the contract.

7.2 Camber

The camber of wide strips and steel sheets shall not exceed 5 mm over any 2,000 mm length; when the length of a steel sheet is less than 2,000 mm, its camber shall not exceed 0.25% of the actual length of the steel sheet. The camber of slit wide strips shall not exceed 2 mm over any 2,000 mm length.

7.3 Out-of-squareness

The steel sheet shall be cut into right angles, and the out-of-squareness shall not exceed 1% of the actual width of the steel sheet when measured by the projection method;

7.4 Telescoping

Wide strips and slit wide strips shall be firmly rolled, and the telescoping height on one side of the wide strip and slit wide strip rolls shall comply with the requirements of Table 10.

8.1 Thickness

The wide strips and steel sheets with mill edges shall be measured at a distance of not less than 40 mm from the rolled edge; wide strips and steel sheets with cut edges shall be measured at a distance of not less than 25 mm from the sheared edge.

8.2 Width

It shall be measured in a direction perpendicular to the center line of the steel sheet, wide strip or slit wide strip.

8.4 Flatness tolerance

8.5 Camber

The camber of wide strip, steel sheet and slit wide strip refers to the maximum distance between the side and the straight line connecting the two end points of the measured part, measured on the concave side of the product, as shown in Figure 2.

8.6 Out-of-squareness

The out-of-squareness of the steel sheet is measured by one of the following two methods.