Peculiarities of Diffusion Processes in Dissimilar Steels Welded Joints

Fetisova, Yekaterina Anatolyevna; Lupachev, A G

doi:10.53078/20778481_2014_3_79

Cited by 3 publications

(5 citation statements)

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“…The fracture energy of the weld metal significantly exceeds the fracture energy of the base metal and the fusion zone. Moreover, the fracture surface of the fusion zone is brittle, and the fracture surfaces of the base metal and the weld metal are ductile [1]. (see Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the formation of decarburized and carburized zones in the welded joint occurred due to the diffusion of carbon caused by the difference in its concentration and thermodynamic activity in the 15Cr5Mo welded steel and ANZhR-2 austenitic filler material [1].…”

Section: Resultsmentioning

confidence: 99%

“…This is especially true for steels alloyed with carbide-forming elements (Cr, V, Ti, Nb, etc. ), which greatly reduce the activity of carbon in such steels [1].…”

Section: Resultsmentioning

confidence: 99%

“…This change in the structure of the fusion zone leads to an abrupt change in properties in a very short section. The decarburized layer is weakened, and the carburized zone is characterized by increased brittleness [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…This technique was used in the manufacture of the industrial pipeline under consideration. However, as a result of the long-term operation and periodic heat loads, the failure of the welded joint in the form of a crack takes place along the fusion line, causing he industrial pipeline to fail as well [1].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Weld Repair Technique for Petroleum Product Pipeline in Extreme Conditions of Prolonged Thermal Cycling

Karatseyeu

Lupachou

Parshin

2023

KEM

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The paper presents the results of experimental research on the development of a repair technique for a pipeline transporting hydrogen mixed with petroleum vapors, which has been in operation for 25 years at Mozyr Oil Refinery, the largest oil enterprise of the Republic of Belarus. The failure of this pipeline was caused by a crack formed in the weld root and its propagation along the fusion line of the heterogeneous weld joint. The developed technique made it possible to prevent further crack propagation without interrupting the refinery fractionation column operation. Welding of the main weld should be performed on a previously deposited damping layer. The damping layer must be deposited by using welding materials, the welding method and the technique that lead to creating a nonoriented dendritic structure. For this purpose, a welding material that has an energy of crack initiation and propagation greater than the energy of crack propagation in the base metal must be used. The composition of the weld must include chemical elements that inhibit the intensity of diffusion processes and increase the strength of the interatomic forces of the austenitic matrix at the pipeline operating temperature.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…This is especially true for steels alloyed with carbide-forming elements (Cr, V, Ti, Nb, etc. ), which greatly reduce the activity of carbon in such steels [1].…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Weld Repair Technique for Petroleum Product Pipeline in Extreme Conditions of Prolonged Thermal Cycling

Karatseyeu

Lupachou

Parshin

2023

KEM

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Increasing the Durability of Butt-Welded Joints Operating under Cyclic Loads in a Biaxial Stress Field

Lyudmirsky

Leonov

Assaulenko

2022

Vestnik Donskogo gosudarstvennogo tehničeskogo universiteta

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Introduction. In sheet and hull structures operating under pressure, destruction, as a rule, is localized along the transition line from the base metal to the weld metal. Methods of increasing the durability of butt-welded joints, which are aimed at reducing stress concentration and creating favorable residual compression stresses, are described.Materials and Methods. The tests were carried out on an installation for biaxial bending, which created a biaxial stress field. Factory-made coupons and samples with an additionally processed transition zone from the weld metal to the base metal were tested. The effectiveness of further processing is shown by the following methods:– abrading;– grit hardening;– abrading with grit hardening;– melting of the fusion line in argon without filler wire;– melting of the fusion line in argon with filler wire EP-410U;– melting of the fusion line without filler wire with plastic deformation between narrow rollers.Results. The origin, development of destruction, and its features were analyzed using different methods of further processing of joint welds. Confidence spans (95 %) of the origin and development of failures for joint welds and base metal were calculated. The efficiency of the proposed methods for further processing was evaluated.Discussion and Conclusions. An analysis of the effectiveness of methods for increasing the durability of butt-welded joints has shown that the creation of a smooth transition from the weld metal to the base metal reduces significantly the stress concentration. This provides increasing the number of cycles before the onset of destruction and the survivability of compounds. Due to compressive stresses in the near-weld area, it is possible to increase the durability of joint welds. The most effective methods of further processing of welds combine the reduction of stress concentration and the creation of residual compression stresses. The high-tech solution is remelting the transition zone in an argon medium with an additional EP-410U filler wire.

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Methods and Equipment for Experimental Evaluation of the Performance of Shell and Hull Structures

Lyudmirsky

Assaulenko

Kramskoi³

2022

Vestnik Donskogo gosudarstvennogo tehničeskogo universiteta

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Introduction. Pressure-operated thick-walled hull structures are the most common type of high-duty welded structures. When these structures are loaded with internal pressure, a complex biaxial stress field arises in them, which is summed up with the fields of residual welding stresses. Therefore, when selecting a technology for manufacturing critical welded structures, the results obtained during conventional uniaxial tests of samples are insufficient. The variety of factors affecting the performance of structures, and the difficulties of separate assessment of their influence, caused the need to maximize the approximation of experimental conditions to the real working conditions of the structure.Materials and Methods. Testing of full-scale structures has a number of advantages, but they are extremely expensive, and, as a rule, only one, the weakest link, is identified, the bearing capacity of the other structural elements remains unclear. For testing, UDI radiometric installations designed for different sample sizes were used. The presented installations allow testing samples of various shapes, types of welded joints (butt, T-bar), changing the position of welded parts.Results. Without rejecting the results obtained during the testing of full-scale structures in the works of the Bauman Moscow State Technical University, DSTU, NRC «Kurchatov Institute» – CRISM «Prometey», and the authors proposed to conduct the basic scope of the research on individual structural elements that would reflect the characteristic features of loading, manufacturing technology, and operating conditions. The design of the «fitting-sheet» connections was applied, which made it possible to increase the indicators of the failure initiation and propagation to the level of the base metal.Discussion and Conclusions. Schemes of structures for obtaining a biaxial tension or bending field in samples were presented. Samples tested according to the proposed schemes allowed us to draw conclusions about the performance of welded joints under conditions close to the actual operation of the structures under study. The proposed test scheme is used by research laboratories in our country and around the world.

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Peculiarities of Diffusion Processes in Dissimilar Steels Welded Joints

Cited by 3 publications

References 0 publications

Weld Repair Technique for Petroleum Product Pipeline in Extreme Conditions of Prolonged Thermal Cycling

Weld Repair Technique for Petroleum Product Pipeline in Extreme Conditions of Prolonged Thermal Cycling

Increasing the Durability of Butt-Welded Joints Operating under Cyclic Loads in a Biaxial Stress Field

Methods and Equipment for Experimental Evaluation of the Performance of Shell and Hull Structures

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