This standard applies to sampling for rolling, forging, cold drawing and extrusion, impact, bending, hardness and upset forging tests. GB 2975-1982 Sampling regulations for mechanical and process performance tests of steel GB2975-1982 standard download decompression password: www.bzxz.net

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National Standard of the People's Republic of China
Steel Mechanical and Process Performance Sampling Regulations
UDC669.142620.11
GB2975-82
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This standard applies to the sampling of tensile, impact, bending, hardness and upset forging tests of rolled, forged, cold drawn and extruded steel. It can also be used as a reference for sampling of other mechanical and process performance tests. If the product standard or the agreement between the two parties stipulates otherwise, it shall be implemented in accordance with the regulations. 1. Cutting of samples
1.1 Samples should be cut from steel with qualified appearance and size. 1.2 When cutting the sample, it should be prevented from affecting its mechanical and process properties due to heat, work hardening and deformation. 1.2.1 When cutting the specimen by burning method, sufficient machining allowance must be left from the specimen cutting line to the edge of the specimen, which should generally not be less than the thickness or diameter of the steel, but the minimum should not be less than 20mm. For steel with a thickness or diameter greater than 60mm, the machining allowance can be appropriately reduced according to the agreement between the two parties.
1.2.2 The machining allowance left for cold shearing specimens can be selected according to the following table: mm
Thickness or diameter
>10~20
>20~35
2 Sample cutting position and direction
Machining allowance
Thickness or diameter
2.1 For round steel, square steel and hexagonal steel with a cross-sectional size (D and a in Figure 1) less than or equal to 60mm, the tensile and impact specimens should be cut at the center; when the cross-sectional size is greater than 60mm, it should be cut at a quarter of the diameter or diagonal from the outer end, as shown in Figure 1. 2.2 When the specimen does not need heat treatment, the round steel, square steel and hexagonal steel with a cross-sectional size less than or equal to 40mm should be tested with the full cross section. When the test machine conditions cannot meet the requirements, it should be processed into the corresponding circular proportional specimen in GB228-76 "Metal Tensile Test Method".
2.3 When the specimen needs heat treatment, it should be cut from the round steel, square steel and hexagonal steel according to the size specified in the relevant product standards. Figure 1
Bending specimens should be cut from the ends of round steel and square steel along the rolling direction. When the cross-sectional size is less than or equal to 35mm, the full cross section of the steel should be used for testing. When the cross-sectional size is greater than 35mm, the round steel shall be processed into a circular specimen with a diameter of 25mm. The surface layer with a width of no more than 5mm shall be retained. The square steel shall be processed into a rectangular specimen with a thickness of 20mm and a surface layer retained, as shown in Figure 2. Figure 2
2.5 Rectangular tensile, bending and impact specimens shall be cut from one quarter of the waist height of I-beams and channel steels along the rolling direction. The thickness of the tensile and bending specimens shall be the thickness of the steel material, as shown in Figure 3. Hope Bookstore
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2.6 Rectangular tensile, bending and impact specimens shall be cut from the leg length of angle steel and B-beam and from one third of the waist height of T-shaped steel and bulb flat steel, as shown in Figure 4.
2. The specimens shall be cut from the end of the flat steel along the rolling direction at one third of the width from the edge.
Rolling direction
Tension, bending and impact specimens shall be cut at one place, as shown in Figure 5. 2.8 If the size of the steel cannot meet the above requirements, the center line of the specimen can be moved to the middle or the whole section can be used for testing. Hope Bookstore
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2.9 Tension, impact and bending specimens shall be cut at the end of the steel plate perpendicular to the rolling direction. For longitudinally rolled steel plates, specimens shall be cut at a distance of one quarter of the plate width from the edge, as shown in Figure 6. For transversely rolled steel plates, specimens may be cut at any position of the width. Rolling direction
2.10 Specimens taken from steel plates and flat steels with a thickness of less than or equal to 25 mm shall be processed into rectangular tensile specimens with the original surface layer retained. When the conditions of the testing machine cannot meet the requirements, it should be processed into a rectangular test specimen with a surface layer retained. When the thickness is greater than 25mm, it should be processed into a corresponding circular proportional specimen in GB228 according to the thickness of the steel material. The center line of the specimen should be as close to the surface of the steel material as possible, that is, a less significant oxide scale should be retained on the head.
2.11 When cutting impact specimens from steel plates, flat steels, I-beams, channels, angles, B-beams, T-beams and bulb flat steels, the surface layer should be retained on one side, and the axis of the impact specimen notch should be perpendicular to the surface layer, as shown in Figure 7. Figure 7
2.12 When measuring strain aging impact toughness, the position of cutting the specimen should be the same as the position of the general impact specimen. 2.13 When the thickness of steel plates and flat steels is less than or equal to 30mm, the thickness of the bending specimen should be the thickness of the steel material; when it is greater than 30mm, the specimen should be processed into a specimen with a thickness of 20mm and retain a surface layer. 2.14 For steel pipes with an outer diameter less than or equal to 30mm, the entire pipe section should be taken as a tensile test specimen. When the outer diameter is greater than 30mm, the pipe should be cut to take a longitudinal Hope Bookstore
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or transverse tensile test specimen. If the test conditions permit, the entire pipe section of the steel pipe with an outer diameter greater than 30mm can also be taken as a tensile test specimen. 2.15 For steel pipes with an outer diameter greater than 30mm, when the wall thickness is less than 8mm, strip tensile test specimens should be made. When the wall thickness is equal to or greater than 8mm, it should be processed into a corresponding circular proportional specimen in GB228 according to the wall thickness. The center line of the specimen should be close to the inner wall of the steel pipe, and the sample location is shown in Figure 8.
2.16 The impact sample of the steel pipe should be cut close to the inner wall, the axis of the notch of the specimen should be perpendicular to the inner wall, and the direction of sampling should comply with the provisions of the relevant product standards.
2.17 Samples for bending, flaring, shrinking, flattening and curling of steel pipes can be cut at any position. 2.18 Samples of steel strips shall be cut from the outer or inner end of each coil. 2.19 Samples of wire rods and steel wires shall be cut from both ends of each coil. 2.20 Hardness samples shall be cut at the same position as tensile samples. The hardness of steel in delivery state is generally measured on the surface. 2.21 For cold and hot upsetting tests of bars of various sizes, unprocessed samples shall be used. For cold upsetting samples with a diameter or side length greater than 30mm, they shall be cut according to product standards. Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by the Central Iron and Steel Research Institute. The main drafter of this standard is Li Jiulin.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB15-64 "Method for Sampling (Sample) of Mechanical and Process Tests of Steel" shall be invalidated.
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