Investigation of Thermal-Deformation State of Welded Joints in Stable-Austenitic Steels and Nickel Alloys

Yushchenko, K. A.; Makhnenko, V. I.; Savchenko, V. S.; Chervyakov, N. O.; Velikoivanenko, E.A.

doi:10.1007/bf03266600

Cited by 6 publications

(2 citation statements)

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“…The difficulties of welding by HNA melting are associated with the low resistance of joints against crystallization and subsolidus cracks, cracking during thermal treatment, as well as ensuring their heat resistance and thermal stability. These issues are predetermined by the melting and overheating of the main metal, as well as the reduction of plasticity in the temperature interval of fragility to zero [8][9][10]. When melting alloys made by the directional crystallization, they lose their original structure.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Designing brazing filler metal for heat-resistant alloys based on NI3AL intermetallide

Kvasnytskyi

Korzhyk²,

Kvasnytskyi

et al. 2020

EEJET

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One of the most promising structural materials in gas turbine engineering is the alloys based on an intermetallide, the type of Ni 3 Al, with an equiaxial and directional columnar structure. These materials make it possible to increase the working temperature of blades to 1,220 °C. The blades are made by the method of precise casting in a vacuum; in this case, it is necessary to technologically join the nozzle blades into blocks, to fix the signal holes in cooled blades, to correct casting defects. Welding by melting intermetallide materials, as well as other cast heat-resistant nickel alloys (HNA), does not yield positive results. Therefore, various brazing techniques are used such as TLP-Bonding (Transient Liquid Phase Bonding). Filler metals' melting point is lower than that of the main metal. The key issue related to the technology of brazing HNA, including the design of appropriate filler metals, is the improvement of the physical-mechanical and operational properties of brazed joints. This paper reports the established rational doping of a filler metal base, as well as depressants, the critical temperatures and surface properties of filler metals, their chemical composition, the structure and properties of brazed joints, the mode parameters, and brazing technology.To improve the stability of the structure and the high-temperature strength of the brazed joints, the filler metal was alloyed with rhenium and tantalum. Mechanical tests of brazed joints at 900 °C were conducted in Ukraine; at a temperature of 1,100 °C -in the People's Republic of China. The test results showed that the short-term strength of alloy compounds with an equiaxial structure based on the Ni 3 Al-type intermetallide at 1,100 °C is 0.98 of the strength of the main metal. The long-lasting strength at the same temperature meets the requirements for the strength of the main metal

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Section: Literature Review and Problem Statementmentioning

confidence: 99%

Designing brazing filler metal for heat-resistant alloys based on NI3AL intermetallide

Kvasnytskyi

Korzhyk²,

Kvasnytskyi

et al. 2020

EEJET

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“…For the considered plate, in the process of welding heating the temperature field T(x, y, z, t) in time was determined. Then, according to the average values of temperature T(x, y, t) the problem of kinetics of the stresses and deformations was solved [5,6]. It was based on the method of successive tracking in time with pitch Δt and the finite element method in space, i.e.…”

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confidence: 99%

Evaluation of thermal stressed state in welded joint of alloy Inconel 690

Chervyakov¹

2015

The Paton Welding J.

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The results of evaluation of thermal stressed state in welded joint of nickel alloy Inconel 690 are presented. The experimental-calculation analysis of thermal processes and mathematical modeling of stress-strain state in single-pass welding was performed. The verification of the data by comparing the experimental thermal cycles with the calculated ones showed a good similarity of results of both as to the sizes of a weld as well as to the thermal cycles in the zones at the different distance from the fusion line. The kinetics of stress-strain state in different zones of welded joint was analyzed considering the probability of hot crack formation. It is shown that under the conditions of modeling linear one-pass welding of plates of 3 mm thickness with energy input of 304 J/mm the arising stresses and deformations do not exceed the critical values and, at the same time do not create the conditions for hot crack formation. The applied mathematical model can be used in evaluation of kinetics of stress-strain state for different variants of welding (change in energy input, different filler material, etc.). 7 Ref., 1 Table, 5 Figures. K e y w o r d s : nonconsumable-electrode arc welding, nickel alloys, thermal processes, thermal cycles, mathematical modeling, stresses, deformationsThe nickel-based alloys play an important role as corrosion-resistant materials in the nuclear and chemical industries, especially under conditions of operation at the high temperatures, considerable stresses and aggressive environments. The widely used nickel-based alloys at the present time are alloys of Ni-Cr-Fe alloying system. One of such alloys is Inconel 690 with high chromium content (30 %) [1]. The welded joints of Inconel 690 with appropriate filler materials showed a high sensitivity to hot crack formation, particularly under the conditions of welding of thick-walled structural elements. The alloys manifest the highest tendency to the formation of ductility-dip cracks [2,3].As was shown previously [4], the ductility-dip cracks in welding of alloys of alloying system Ni-Cr-Fe occur at the temperature range of 1050-650 °C, the value of critical deformation of crack formation ε cr is about 1.2 %.The thermal processes in fusion welding have a decisive influence on the nature and kinetics of changes in the stress-strain state, structure and properties of weld and HAZ. In this regard, the analysis of temperature fields in welding of alloys of Ni-Cr-Fe alloying system with the aim of further investigations of kinetics of stress-strain state and evaluation of tendency to hot crack formation is an urgent problem.The aim of the work was a comparative experimental and calculation analysis of temperature fields and modeling of stress-strain state in one-pass argon-arc welding of alloy Inconel 690.The computer prediction and calculation allow determining the temperature fields for different values of thermal power of the arc. Using the calculation procedure the efficiency coefficient of the arc is established, which varies depending on the ...

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New Approaches in Evaluation of Mechanical Characteristics and Microstructure of Restored Parts of GTE from Nickel Heat-Resistant Alloys

Yushchenko¹,

Zviagintseva²,

Yarovytsyn³

et al. 2019

Metallofiz. Noveishie Tekhnol.

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Investigation of Thermal-Deformation State of Welded Joints in Stable-Austenitic Steels and Nickel Alloys

Cited by 6 publications

References 0 publications

Designing brazing filler metal for heat-resistant alloys based on NI3AL intermetallide

Designing brazing filler metal for heat-resistant alloys based on NI3AL intermetallide

Evaluation of thermal stressed state in welded joint of alloy Inconel 690

New Approaches in Evaluation of Mechanical Characteristics and Microstructure of Restored Parts of GTE from Nickel Heat-Resistant Alloys

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