GB/T 5293-2018Solid wire electrodes, tubular cored electrodes and electrode/flux combinations for submerged arc welding of nonalloy and fine grain steels (English PDF)

5.2 Chemical analysis

5.2.1 Solid wire

For chemical composition analysis of solid wire, sampling shall be done on the finished wires. Copper-free wire samples can be taken on the raw materials of the manufactured products; however, for arbitration tests, sample the finished products.

5.2.2 Flux-cored wire

For deposited metal chemical analysis, samples of flux-cored wire matching the corresponding flux shall be prepared according to the GB/T 25777. It can also be prepared on the mechanical property specimens or the torn tensile rod. For arbitration tests, prepare in accordance with the GB/T 25777.

5.2.3 Analytical methods

Chemical composition analysis can be carried out by any suitable analytical method, The arbitration test shall be conducted by analytical method agreed by both parties.

5.3 Mechanical property tests

5.3.1 Base metal for testing

5.3.1.1 The base metal for the mechanical property test of the multipass weld deposited metal with the combination of wire and flux shall be made of a steel plate corresponding to the chemical composition of the deposited metal. If other base metal is used, the test welding material or other equivalent welding material shall be used to weld the isolating layer on the groove surface and the gasket surface, the thickness of which shall be not less than 3 mm after processing.

5.3.1.2 For the classification tests of double-sided single-pass welded joints with the combination of wire and flux, the base metal shall be steel plate with equivalent tensile strength. The difference of strength grade shall not be greater than 50 MPa.

5.3.2 Specification for fluxes drying

Before welding, the flux shall be dried at 250°C ~ 400°C for 1h ~ 2h or as per manufacturer's recommendation.

5.3.3 Preparation of specimens

5.3.3.1 Preparation of multi-pass welded deposited metal specimens

Prepare the metal specimens for mechanical properties of multi-pass weld deposited metal according to GB/T 25774.1. The specimen type shall be 1.4 and the welded joint as per GB/T 25774.2. The specimen type is 2.5. When weld with solid or flux-cored wire, the welding shall be carried out in accordance with manufacturer's recommendation.

The flux suitable for single-sided single-pass welding can be tested as this type of specimen.

5.3.4 Tensile tests

5.3.4.1 Tensile test of multi-pass welded deposited metals

The size and sampling point of the multi-pass weld deposited metal for tensile test shall be in accordance with GB/T 25774.1. The tensile test shall be carried out according to GB/T 2652.

5.3.4.2 Tensile test of double-sided single-pass welded joints

The size and sampling point of the double-sided single-pass welded joint for tensile test shall be in accordance with GB/T 25774.2. The transverse tensile test shall be carried out according to GB/T 2651.

5.3.5 Impact tests

5.3.5.1 The size and sampling point of multi-pass welding impact specimen are specified in GB/T 25774.1. The specimen size and sampling point of double-sided single-pass welding for impact test is specified in GB/T 25774.2.

5.3.5.2 In each set of the impact specimens, there shall be at least one sample for measuring the shape and size of the V-shaped notch. The measurement shall be done by a projector or metallographic microscope with at least 50x magnifications.

5.3.5.3 The impact test of V notch shall be carried out according to GB/T 2650.

5.4 Ray inspection

5.4.1 The radiographic inspection of Multi-pass welding and double-sided single-pass weld shall be carried out before the tensile and impact specimens are taken. The gasket (if used) shall be removed before the radiographic inspection.

5.4.2 Weld ray inspection test shall be carried out according to GB/T 3323.

5.4.3 When evaluating the ray inspection negative film, the 25mm at both ends of the specimen shall not be considered.

5.5 Diffusion hydrogen test for deposited metals

The diffusion hydrogen content of deposited metal shall be determined by GB/T

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