GB/T 2649-1989

Methods of Sampling for Mechanical Properties Tests of Welded Joint

Standard Number: GB 2649-89

Replaces: GB 2649-81

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1 Scope

This standard specifies the methods of sampling for mechanical properties tests of welded joints, including tension, impact, bending, flattening, hardness, and resistance spot weld cutting tests of metal materials. This standard is applicable to fusion welded and pressure welded joints.

2 Terms

• Test plate: Plate material used for manufacturing test specimens (including section bar, pipe material).
• Specimen blank: Specimen blank taken from the test plate.

3 Preparation of Test Specimens

3.1 The sampling position of the test plate shall conform to relevant product manufacturing specifications or metal product standards.

3.2 Test plate material, welding material, welding conditions, and preheating before welding and post-weld heat treatment specifications, etc., should be the same as relevant standards or product manufacturing specifications, or comply with relevant test condition specifications.

3.3 Specimen dimensions should be comprehensively considered based on specimen size, quantity, cut width, machining allowance, and unusable areas (such as starting and ending tabs of arc weld). The length of unusable areas is related to specimen thickness and welding process, but must not be less than 25mm (except when using starting tabs, ending tabs, and pipe joint test pieces).

3.4 When extracting specimen blanks from test specimens, if relevant standards or product manufacturing specifications do not specify otherwise, specimen blanks may be slightly curved.

3.5 Angular deviation or offset of test specimens should comply with relevant standards or product manufacturing specification requirements.

3.6 Test specimens may be marked by any method, but must be clear, and the marking position should be outside the test area.

4 Sampling Position and Quantity of Specimens

4.1 When extracting specimen blanks from test specimens, mechanical cutting methods should be used as much as possible. Specimens may also be cut by shearing, thermal cutting, and other methods, but machining allowance must be considered. In all cases, the metal in the test area must not be affected by cutting. When thermal cutting is used, the distance from the steel thermal cut surface to the specimen edge must not be less than 8mm, and decreases with cutting speed reduction and increases with cutting thickness.

4.2 The sampling position of specimens for various test methods should comply with the following specifications.

4.2.1 The sampling position of tension and impact specimens for weld metal and fusion metal shall be shown in Table 1, Table 2, and Table 3.

4.2.1.1 When there is no special specification for multi-layer weld specimen position, sampling should be as close as possible to the surface layer of the last pass of the weld, with the cover weld removed.

4.2.1.2 When specimen thickness is greater than 100mm or weld thickness H is greater than 60mm, specimen sampling position should be executed according to product specifications.

Table 1 – Sampling Position of Fusion Metal Tension Specimen (mm)

Test Specimen Thickness	Welding Method	Specimen Position	Notes
≤ 12	Arc weld or gas weld	Used when weld material and test plate are the same material	Two layers of cover weld should be applied on the bevel surface, and its thickness should be greater than 3mm.

Note: S — Test specimen thickness.

4.3 Specimen Quantity

When relevant standards or product manufacturing specifications do not specify otherwise, the specimen quantity for various test methods:

• Joint tension: not less than 1 specimen
• Fusion metal and weld metal tension: not less than 1 specimen each
• Full pipe joint tension: 1 specimen
• Pipe joint strip tension: not less than 2 specimens
• Face bend, root bend, side bend: not less than 1 specimen each
• Longitudinal bend: not less than 2 specimens
• Joint impact: not less than 3 specimens
• Spot welded joint shear: not less than 5 specimens
• Pipe joint flattening: not less than 1 specimen
• Joint and weld metal hardness: not less than 1 specimen

4.4 Spot Welded Joint Shear Specimen Position

As shown in Figure 1 (see original PDF for diagram).

4.5 Joint and Weld Metal Hardness Specimen

Hardness specimens should be taken perpendicular to the weld axis and along the corresponding areas in the longitudinal direction of the weld.

4.6 Specimen Sampling Position

Specimen sampling positions should be reasonably arranged within the effective utilization length of the test specimen based on the weld appearance and non-destructive testing results.

4.7 Pipe Joint Flattening Specimen Position

As shown in Figure 2(a) and (b) (see original PDF for diagrams).

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Appendix Notes:

• This standard was proposed by the Ministry of Machinery and Electronics Industry.
• This standard was under the jurisdiction of the Tianjin Welding Research Institute of the Ministry of Machinery and Electronics Industry.
• This standard was drafted by the Tianjin Welding Research Institute of the Ministry of Machinery and Electronics Industry and the Tianjin Commodity Inspection Bureau.
• This standard was drafted by: Tan Tao, Tan Shouli, Liu Yongmei.

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Original PDF Document

Download the original Chinese standard document:

⬇️ GB/T 2649-1989 (Original PDF)