Transverse crack sensitivity test device and method based on composite restraint

Abstract

The invention discloses a transverse crack sensitivity test device based on composite restraint, which comprises a restraint frame and a heating device, the restraint frame comprises two restraint plates and a support column group arranged between the two restraint plates, a welding test plate welded with a test weld bead is arranged between the two restraint plates, the direction of the test weld bead is perpendicular to the restraint plates, and the heating device is arranged on the support column group. The two end faces of the welding test plate and the two ends of the test weld bead are fixedly connected with the two restraining plates respectively. The invention also discloses a test method based on the test device. The test method comprises the following steps: firstly, applying a self-restraint tensile stress or strain parallel to the direction of the test weld bead to the test weld bead in the restraint frame, and then continuously applying a tensile restraint stress or strain with a higher numerical value to the test weld bead in a loading mode of heating and extending the support column. The device can simulate the environment and constraint conditions in a laboratory, can reproduce multi-layer and multi-pass welding transverse cracks of an actual engineering structure, is simple to operate, and provides large-tonnage external constraint force at low cost.

Description

technical field [0001] The invention relates to welding crack sensitivity evaluation technology, in particular to a transverse crack sensitivity test device and method combining external restraint and self-restraint. Background technique [0002] At present, in various industries such as construction, bridge, ship and ocean engineering, construction machinery, electric power, metallurgy, petrochemical industry, etc., welded structures are rapidly replacing other structural forms and penetrating into various related fields. The requirements for service safety and reliability are also getting higher and higher, especially the requirements for welding crack control are getting higher and higher. Even so, in recent years, a large number of weld transverse cracks have appeared in a series of engineering projects and scientific research projects such as domestic and foreign ships and ocean engineering, nuclear power equipment, chemical containers and pipelines, long-distance oil a...

AI Technical Summary

Problems solved by technology

[0005] It is precisely because there are many factors affecting welding transverse cracks, the mechanism is very intricate, and various factors are coupled or synergistic, so a test method that can easily reproduce the transverse sensitivity of multi-layer and multi-pass weld metal in the laboratory is invented. It is one of the most critical technologies for studying the mechanism of welding transverse cracks and developing high-performance welding materials and welding processes with extremely low crack sensitivity

[0006] Several existing test methods for welding transverse cracks, such as G-BOP crack sensitivity test method, rigid fixed crack sensitivity test method, variable restraint crack sensitivity test method, etc., have many problems and are difficult to solve. Reproduce the emergence of transverse cracks in multi-pass multi-layer welding in the laboratory

For example, the G-BOP method is a self-restraint test only applicable to the susceptibility to transverse cracks in single-pass welding; the rigid fixed crack sensitivity test method is also a purely self-restraint welding crack susceptibility test method. The level is far lower than the actual engineering structure, and cannot accurately reproduce the occurrence of welding transverse cracks on the engineering site

The variable restraint is a welding crack susceptibility test method with external restraint by the testing machine. However, hydraulic and electronic tensile testing machines are generally used to provide external restraint force or restraint stress. Due to the limited tonnage of the testing machine, the The restraint force or restraint stress is very limited (generally no more than 2000KN), which cannot meet the restraint requirements required to reproduce the transverse cracks of multi-layer and multi-pass weld metal in the laboratory

Even if a super-large tonnage testing machine with a capacity of more than 10,000KN is used, the cost of the test is too high, so it is not feasible

That is to say, so far, there is still a lack of a low-cost test technology that can easily simulate the environment and restraint conditions in the laboratory and reproduce the transverse cracks of multi-layer and multi-pass welding in actual engineering structures.

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