GB/T 24511-2017Stainless steel and heat resisting steel plate, sheet and strip for pressure equipment (English PDF)

5.1 Dimensions and allowable deviation

5.1.1 Dimensions

The nominal size range of steel plate strip is as shown in Table 1.The recommended nominal size shall meet the requirements of GB/T 708 and GB/T 709.

5.1.3 Allowable deviation of width

5.1.3.1 The hot-rolled thick steel plate shall be delivered after trimmed; the allowable deviation of width shall meet the requirements of Table 5.

Table 5 (continued), in mm

5.1.3.2 The hot-rolled coil-cut steel plate shall be delivered after trimmed. The allowable deviation of the width of the trimmed hot-rolled steel sheet and steel strip, as well as the coil-cut steel sheet shall meet the requirements in Table 6.

The allowable deviation of the width of the non-trimmed hot-rolled steel strip shall be negotiated between the supplier and the buyer.

5.1.3.3 Cold-rolled steel plates and steel strips shall be delivered after trimmed.

The allowable deviation of width shall meet the requirements of Table 7.

5.1.4 Allowable deviation of length

The allowable deviation of the length of hot-rolled thick steel plate, hot-rolled coil-cut steel plate, cold-rolled coil-cut steel plate shall meet the requirements of Table 8.

5.2 Appearance

5.2.1 Sickle bend

The sickle bend of hot-rolled thick steel plate, hot-rolled steel strip and coil-cut steel plate, cold-rolled steel strip and coil-cut steel plate shall meet the requirements of Table 9.

5.2.2 Cutting slope

5.2.3 Unevenness

5.2.4 Tower shape

5.2.4.1 Tower shape. the phenomenon that the edges of the steel coil are not in the same vertical plane during the coiling process, as shown in Figure 1.

5.2.4.2 The steel coil shall be firmly formed into a coil and try to keep cylindrical and not crimped.

5.2.4.3 The tower shape of the hot-rolled trimmed steel coil shall not be larger than 30.0 mm; the tower shape of the cold-rolled trimmed steel coil shall not be larger than 20.0 mm.

5.2.4.4 The tower shape of untrimmed steel coils shall not be larger than 70.0 mm.

5.3 Weight

5.3.1 Weight of steel plate

Steel plates are delivered according to theoretical or actual weight. When calculating the theoretical weight, use the nominal size of the steel plate for calculation, but the calculated thickness is the arithmetic average of the maximum and minimum allowable thickness of the steel plate. See Appendix A for the density of stainless-steel.

5.3.2 Weight of steel strip

The steel strip is delivered according to actual weight.

6.1 Manufacturing method

6.1.1 Use crude molten steel for refining outside the furnace.

6.1.2 The compression ratio of the continuous casting billet or steel ingot shall not be less than 3.

6.1.3 Hot-rolled stainless-steel and heat-resisting steel coils which have a thickness of 14.0 mm ~ 25.0 mm may be flattened in the hot-rolled state and subjected to single-sheet heat treatment, before they can be delivered in accordance with the standard of single sheet medium plate.

6.2 Chemical composition

6.2.1 The steel designation and chemical composition (melting analysis) shall meet the requirements of Table 13 ~ Table 15.Refer to Appendix B for the comparison of stainless-steel designations.

6.2.2 The allowable deviation of the chemical composition of the finished

product of steel plates and steel strips shall meet the requirements of GB/T 222.

6.2.3 Stainless-steel pitting equivalent number PREN = Cr% + 3.3Mo% + 16N%.

6.3 Delivery status

After cold rolling or hot rolling of steel plates and steel strips, refer to Appendix

C for heat treatment; deliver them after pickling or similar treatment.

6.4 Mechanical properties and process properties

6.4.1 The room temperature mechanical properties of heat-treated steel plates

and strips shall meet the requirements of 6.4.2 ~ 6.4.For several different hardness tests, one of the methods can be tested according to the different sizes and conditions of steel plates and strips.

6.4.2 The room temperature mechanical properties of the solid-solution-treated

austenitic stainless-steel shall meet the requirements of Table 16.

6.4.3 For hot-rolled thick steel plates, when the thickness exceeds the

maximum thickness as specified in Table 2, the mechanical property test can be carried out after negotiation between the supplier and the buyer. The test data is for reference only and not as a basis for delivery.

6.4.4 The room temperature mechanical properties of the austenitic-ferritic steel

after solid-solution treatment shall meet the requirements of Table 17.

6.4.5 The room temperature mechanical properties and process properties of

the annealed ferritic steel shall meet the requirements of Table 18.

6.4.6 For the bending test of the annealed ferritic steel, the inspection shall be carried out only when required by the purchaser and specified in the contract.

6.4.7 Refer to Appendix D and Appendix E for the high temperature mechanical

properties of some designations.

6.6 Grain size

According to the requirements of the buyer, as negotiated between the supplier and the buyer and indicated in the contract, the stainless-steel whose designation is 07Cr19Ni10, 07Cr17Ni12Mo2, 07Cr19Ni11Ti, 07Cr18Ni11Nb can be subject to the grain size testing. The level of average grain size shall be 7 or coarser.

6.7 Surface processing and quality requirements

6.7.1 Surface processing types of steel plates and strips

The surface processing types of steel plates and strips are as shown in Table

19.The purchaser shall specify the processing type according to the use requirements and indicate in the contract.

6.7.2 Surface quality

6.7.2.1 Surface quality of hot-rolled thick steel plates, hot-rolled steel

strips, coil-cut steel plates

Steel plates and steel strips are not allowed to have defects that affect their use.

The surface of steel plate and steel strip after pickling is not allowed to have oxide scale or over pickling. It is allowed to grind and clean local defects on the surface of the steel plate, but the minimum thickness of the steel plate shall be guaranteed. Since steel strips generally have no chance of removing defects, it is allowed to have a small amount of abnormal parts.

6.7.2.2 Surface quality of cold-rolled steel strip and coil-cut steel plate

6.8 Special requirements

6.8.1 According to the requirements of the buyer and after the agreement

between the supplier and the buyer, special technical requirements can be specified for the chemical composition, mechanical properties, non-metallic inclusions of the steel plate and steel strip, or special inspection items such as corrosion resistance test and non-destructive testing can be supplemented. The test method and qualification level shall be determined through negotiation between the supplier and the buyer and indicated in the contract.

6.8.2 According to the requirements of the purchaser and specified in the

contract, the comparison test of austenitic-ferritic stainless-steel is carried out in accordance with GB/T 13305, requiring a ferrite content of 40% ~ 60%.

7.3 Measurement method of size and shape

7.3.1 Dimension measurement

7.3.1.1 Thickness measurement

7.3.1.2 Width measurement

Width measurement position. Perpendicular to the rolling direction, except for the abnormal part of the head and tail of untrimmed steel strip.

7.3.2 Shape measurement

7.3.2.1 Sickle bend

The measurement method is as shown in Figure 2, except for the abnormal part of the head and tail of untrimmed steel strip.

Description.

7.3.2.3 Unevenness of steel plate

8.3 The sampling quantity and sampling location of each batch of steel plates

and strips shall meet the requirements of Table 20.

8.4 The re-inspection and determination of other inspection items shall meet the requirements of GB/T 17505.

8.5 The test results of mechanical properties and chemical composition shall be rounded off using the rounding value comparison method; the rounding off rules shall be implemented in accordance with the provisions of GB/T 8170.