Cracks In Welded Joints Research Articles

Distinctive features of damage to low-pressure deaerators of heat-electric power plants

We investigate causes of corrosion cracking of welded joints of low-pressure deaerators of heat-electric power plants and give recommendations for their repair with subsequent heat treatment of welds, which guarantees an increase in their corrosion crack resistance under operating conditions.

Magnetographic detection of cracks in welded joints : Sharova, A.M.; Strel'skaya, M.A.; Magilinskii, A.P.; Davydkov, A.A. Technical Diagnostics and Nondestructive Testing, Vol. 2, No. 2, pp. 137–139 (Apr.–Jun. 1990)

Magnetographic detection of cracks in welded joints : Sharova, A.M.; Strel'skaya, M.A.; Magilinskii, A.P.; Davydkov, A.A. Technical Diagnostics and Nondestructive Testing, Vol. 2, No. 2, pp. 137–139 (Apr.–Jun. 1990)

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes : Golovinskii, A.G.; Kiselev, A.V.; Kotkis, A.M.; Khokhlov, N.F.: Shiryaev, A.M. Soviet Journal of Nondestructive Testing, Vol. 26, No. 8, pp. 540–544 (Apr. 1991)

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes : Golovinskii, A.G.; Kiselev, A.V.; Kotkis, A.M.; Khokhlov, N.F.: Shiryaev, A.M. Soviet Journal of Nondestructive Testing, Vol. 26, No. 8, pp. 540–544 (Apr. 1991)

Modelling cracks in welded joints : Fomichev, S.K.; Zhdanov, I.M. Technical Diagnostics and Nondestructive Testing, Vol. 5, No. 1, pp. 60–63 (Jan.–Mar. 1993)

Modelling cracks in welded joints : Fomichev, S.K.; Zhdanov, I.M. Technical Diagnostics and Nondestructive Testing, Vol. 5, No. 1, pp. 60–63 (Jan.–Mar. 1993)

Design and testing of equipment for nondestructive detection and identification of the location and dimensions of materials defects, especially of cracks in welded joints of pipe systems (In German, English abstract) : Wuensch, W. Bundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany), TIBB94-02356/GAR, 196pp. (Feb. 1992)

Design and testing of equipment for nondestructive detection and identification of the location and dimensions of materials defects, especially of cracks in welded joints of pipe systems (In German, English abstract) : Wuensch, W. Bundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany), TIBB94-02356/GAR, 196pp. (Feb. 1992)

Using the acoustic emission method for examining the process of formation of cold cracks in welded joints in a high-strength steel : Musiychenko, V.F.; Zhdanov, S.L. Technical Translations, 7 Meadow Walk, Great Abington, Cambridge, U.K.. 7m). (1984). No. VR/3852

Using the acoustic emission method for examining the process of formation of cold cracks in welded joints in a high-strength steel : Musiychenko, V.F.; Zhdanov, S.L. Technical Translations, 7 Meadow Walk, Great Abington, Cambridge, U.K.. 7m). (1984). No. VR/3852

Crack significance evaluation with special reference to welded structures

Fracture mechanics parameters (stress intensity factorK I and its critical valueK Ic , crack opening displacement, and the contourJ integral) are originally defined for static and quasistatic loading conditions. On the basis of theoretical background, standard test methods for the experimental determination of their specific values were developed. Structural integrity analysis requires the extension of application of these parameters to other types of loading. We propose new parameters for stress corrosion (stress corrosion cracking thresholdK 1sco ), for cyclic loading (stress intensity factor range ΔK and fatigue threshold ΔK th), and for creeping at elevated temperatures (C * andC t integrals). The structural integrity of welded structures is mainly affected by cracks in welded joints. We demonstrate the practical application of fracture mechanics parameters to the evaluation of structural integrity under the above-mentioned loading conditions.

Cold cracks in welded joints of structural steels

The present survey is devoted to the investigation of a dangerous phenomenon (quite often observed in the process of arc welding) of the formation of hydrogen-induced cold cracks in welded joints of structural steels. We briefly analyze the existing models of the mechanism of hydrogen embrittlement. It is shown that difficulties in understanding the processes of initiation and growth of cold cracks are explained not only by the necessity of determination of the principal factors which govern the embrittling action of hydrogen but also by the absence of reliable knowledge of the microscopic mechanisms of fracture processes in metals. We suggest a new model of hydrogen embrittlement of metals with bcc lattice developed at the Paton Institute of Electric Welding. According to this model, atomic hydrogen adsorbed on the metal surface in the form of anions affects the surface energy of submicrocracks appearing in dislocation clusters in the process of deformation whose initial period of propagation obeys the classical Griffith scheme. The proposed model enables one to explain all known distinctive features of the cold cracking of welded joints and forms a groundwork for the physical simulation based the use of mathematical methods and aimed at the quantitative evaluation of the contribution of each factor to the indicated processes.

High-temperature ductility of nickel alloys type KhN55MBYu with a high iron content

In order to prepare stamped and welded structures which operate in the temperature range from 750 to −253°C there is use of high-strength dispersion-hardening nickel alloys KhN55MBYu (EP666) and KhN58MBYuD (EK61) which exhibit resistance to hot crack formation during welding and cracking of welded joints during defonnation. Alloys of this type have a high level of strength (σf = 1300 N/mm2 at 20°C) and toughness at cryogenic temperatures, and they have high resistance to plastic deformation in the temperature range for hot pressing especially in the cast condition. In order to find the optimum forging and stamping schedules for these alloys features of the change in their structure and properties in relation to the forming temperature have been studied.

Sulfide Stress Corrosion Cracking in Welded Joints of Welded Linepipes.

The sulfide stress cracking (SSC) behavior of welded linepipes has been studied using some SSC tests, such as tensile SSC test (NACE-TM 0177-90 Method A), full thickness SSC tests, four points bending SSC tests and full scale SSC tests. Detailed metallographic examinations have been performed in order to understand the influences of steel chemistries and heat inputs in welding on the SSC resistance of the heat affected zone. The effects of the geometry of the SSC specimen and hydrogen concentration on the SSC have also been investigated. The results have indicated that homogenized bainitic ferrite microstructure, which can be attained by reducing carbon content and by applying accelerated cooling after controlled rolling in plate rolling process, improves the resistance of steel plates to the SSC. Meanwhile, most specimens from submerged arc welding welded joints fail at the heat affected zone, regardless of differences in the microstructures of base materials, and they tend to show nearly the same level of the ratio of threshold stress to yield strength in the tensile SSC test. Specimen geometry and the quantity of hydrogen concentration in steel affect on the threshold stress, and hence reducing the hydrogen concentration improves the SSC resistance of the welded joints especially in lower hardness heat affected zone. Relations between the results of the laboratory tests and full scale tests are also discussed.

Corrosion cracking in welded joints in corrosion-resistant chrome-nickel-molybdenum steels

Corrosion cracking in welded joints in corrosion-resistant chrome-nickel-molybdenum steels

Effect of microchemical heterogeneity on weld zone cracking of welded joints in nickel alloys in dispersion hardening

Effect of microchemical heterogeneity on weld zone cracking of welded joints in nickel alloys in dispersion hardening

Corrosion cracking of welded joints in a pipe steel in a hydrogen-sulfide medium

1. The maximum long-term corrosion strength in the NACE solution was recorded for the specimens welded under the conditions of specimens 2 (3.0 kJ/mm); their threshold stress was equal to 250 MPa (0.7σ0.2); for other types of specimens welded with a heat input of 6.0 kJ/mm and 1.25 kJ/mm the threshold stress was equal to 180 and 160 MPa, respectively.

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes

Special features of acoustic emission from fatigue cracks in welded joints in oil pipes

Corrosion cracking in welded joints in chrome-nickel austenitic steel

Corrosion cracking resistance has been examined in chloride, alkaline, and hydrogen-sulfide bearing solutions for welded joints in 12Kh18N10T steel made with high-alloy and equivalent metal wires, together with the resistance of those joints to intercrystallite corrosion.

Corrosion cracking of welded joints in low-alloy steels in a hydrogen sulfide-bearing medium

Corrosion cracking of welded joints in low-alloy steels in a hydrogen sulfide-bearing medium

Fatigue crack nucleation in metallic materials: Polak, J.Acta Tech. CSAV 1990 35, (2), 156–174

Aluminium alloy 5083 is used in the fabrication of lightweight, high-speed marine vessels. The high cyclic service stresses on such structures render welded joints in them fatigue-critical. This paper presents experimental investigations on fatigue crack behaviour of welded 5083-H321 aluminium alloy plates. Crack propagation in the heat-affected zone of welded specimens was determined from tests conducted on single edge-notched tension specimens. Three-dimensional finite-element analysis was employed to determine stress intensity factors for cracks in the weld line. The crack closure effects of weld residual stresses were evaluated. The residual stresses significantly influence the crack growth rates. Fatigue behaviour of weld repairs in cracked plates was also investigated. The weld-repair process significantly increases the grain size and the size of defects in the heat-affected zone. The results indicate that weld repair of cracks in welded joints provides little improvement in residual life.

Propagation of short cracks in welded joints in steam lines

Propagation of short cracks in welded joints in steam lines

Special features of evaluating hydrogen cracking of welded joints

Special features of evaluating hydrogen cracking of welded joints

ＭＡＧ狭開先溶接の凝固割れ試験法と凝固割れにおよぼすボロンの影響

This research was carried out to develop a new type of testing method on the solidification cracking of welded joints and to clarify effects of experimental parameters and glass fiber tape backing on cracking.Results obtained in this study are summarized as follows; the experimental result revealed that the local tensile force method was quite effective to reproduce solidification cracking in narrow gap welded joints in a laboratory. The crack length considerably depended on the strain rates. The effect of boron contents in glass fiber tape backing was not so significant to the solidification cracking tendency under normal welding procedures.