GOST 7122-81

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  ГОСТ 7122-81

GOST 7122−81 Seams are welded and the weld metal. Methods of sampling for the determination of chemical composition

GOST 7122−81

Group B09

STATE STANDARD OF THE USSR

THE SEAMS ARE WELDED AND THE WELD METAL

Methods of sampling for the determination of chemical composition

Weld seams and all — weld metal. Methods of sample
selection for determination of chemical composition

Date of introduction 1982−01−01

APPROVED by the Decree of the USSR State Committee for standards 5 February, 1981, No. 488

REPLACE GOST 7122−75

REPRINTING. 1995

This standard specifies methods of sampling to determine the average, layer-by-layer and povelyanovo chemical composition of weld or deposited metal, obtained by fusion welding, single layer and multilayer metallic materials and alloys of homogeneous and dissimilar welded materials.

The standard does not apply to welds made without the use of filler metal diffusion or contact welding, friction welding, etc.

1. SAMPLING METHOD

1.1. The sample should be selected from welds or welded products specifically specimens from the weld metal products or metal, especially for weld samples.

1.2. Welding or surfacing of samples should be conducted, if not possible to take samples directly from welded joints and testing of welding materials.

1.3. A sample is taken from any part of welds or weld metal along their length, excluding the unused beginning and ending sections of the welds or weld metal specimens.

1.4. Length of unused land, as well as the length of the welds or weld metal specimens specially cooked, excluding unused areas are given in table.1.

Table 1

1.5. The sampling site at the cross section of the weld or weld metal must be established in normative technical documentation for products or welding products.

1.6. Before sampling the surface of the weld or weld metal should be thoroughly cleaned from scale, rust and mechanical contaminants.

1.7. To delineate the metal that is to be analyzed, should be cut the appropriate areas of the weld or weld metal products or samples. Sections are cut mechanically, a gas or plasma cutting. If you cut sections of the weld or weld metal is not possible, then to delineate the metal that is to be analyzed, they must be drilled two holes on the drawing. The diameter of the drilled holes needs to go beyond the analyzed metal.

1.8. If the boundaries of the weld or deposited metal can not be fixed by the inspection, without additional processing, the ends of cut sections and the surface of the drilled holes needs to be sanded and etched.

1.9. When applied to cut sections of the gas or plasma cutting ends of the weld or weld metal before polishing must be removed mechanically, a layer of metal of thickness not less than 5 mm.

1.10. After etching at the end of the cut site is necessary to identify the core boundaries of metal for sampling, which should defend from the line of fusion of the weld metal or weld metal with the base metal at a distance of 2.5 is 3.0 mm in the direction of the analyzed metal.

When layered and pavlikova analysis abroad the analyzed metal should be taken of the investigated boundary layer or cushion with the neighboring layers or cushions.

1.11. Sampling should be conducted within the analyzed metals: turning, planing, milling or drilling.

In selecting the sample for the determination of layered or povelyanovo the chemical composition of the drilling is allowed only in the case that the thickness of the analyzed metal not less than 10 mm or if the sampling is done by drilling along the axis of the weld or hardfacing.

Allowed prior to sampling to carry out heat treatment of the cut site to improve the machinability of the analyzed metal with the adoption of measures to prevent the change of its chemical composition.

1.12 To determine the average chemical composition of the weld sampling should be conducted on the weld axis to the border of the analyzed metal.

1.13. It is allowed to conduct sampling of the chips obtained in the processing of calculated samples type I and II according to GOST 6996−66, subject to the entering of the head of the sample boundaries in the analyzed metal.

1.14. When the sampling tool should be clean and fat-free. Allowed to cool tool to use distilled water.

1.15. The hardness of the tool for sampling should be not less than 1.5 times of hardness of the analyzed metal.

1.16. The cutting speed should be chosen such that the chips had no tint.

1.17. Chips selected for the chemical analysis of the weld or weld metal should not contain impurities and must be Packed in a container that protects it from contamination.

Chips should be as even as possible, with thickness 0.3−0.4 mm and short.

1.18. The sample mass for chemical analysis — in accordance with the requirements of GOST 12344−88, 12346−78 GOST, GOST 12347−77, 12348−78 GOST, GOST 12350−78, 12353−78 GOST, GOST 12355−78, GOST 11739.1−90 — GOST 11739.24−82, GOST 13938.1−78 — GOST 13938.12−78, GOST 13938.13−93, and for spectral analysis — from the data given in table. 2.

Table 2

1.19. The analyzed surface samples for spectral analysis must be processed by turning, planing or milling. After processing on the surface of the sample should not be shrinkage cavities, pores and inclusions. The surface roughness must be 80 µm according to GOST 2789−73.

2. SAFETY REQUIREMENTS

When sampling from the weld or weld metal are required to comply with the safety requirements according to GOST 12.3.002−75, GOST 12.3.003−86, GOST 12.3.004−75, GOST 12.2.009−80.