Predicting Susceptibility to Solidification Cracking and Liquation Cracking by CALPHAD

In welding, liquation cracking can occur in the partially melted zone, leaving open cracks along the edge of the weld bead. Likewise, solidification cracking can occur in the mushy zone, leaving open cracks inside the weld bead (which is called the weld metal or fusion zone). The present study aims at demonstrating that CALPHAD-based modeling can help predict the susceptibility of alloys to both types of cracking. The basic relationship between temperature T and the fraction of solid fS of an alloy can be calculated using thermodynamic software and a database based on the alloy composition. For liquation cracking the T-fS curve of the weld metal can be compared with that of the workpiece to assess the susceptibility. For solidification cracking, on the other hand, the T-(fS)1/2 curve of the weld metal can be used to calculate the susceptibility. The composition of the weld metal depends on the compositions of the workpiece and the filler metal, and the percentage of the workpiece in the weld metal (called dilution). The susceptibility predictions based on these curves and comparison with welding experiments will be demonstrated using Al alloys, Mg alloys, and carbon steels as examples.

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Evaluation of solidification cracking susceptibility in ERNiCr-3 (Filler Metal 82) weld metal using the cast pin tear test

Welding in the World ◽

10.1007/s40194-017-0473-6 ◽

2017 ◽

Vol 61 (5) ◽

pp. 935-944

Author(s):

Michael R. Orr ◽

John C. Lippold ◽

Frank Argentine

Keyword(s):

Weld Metal ◽

Filler Metal ◽

Solidification Cracking ◽

Cast Pin Tear Test

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Microstructural evolution and liquation cracking in the partially melted zone of deposited ERNiCrFe-13 filler metal subjected to TIG refusion

Welding in the World ◽

10.1007/s40194-021-01073-8 ◽

2021 ◽

Author(s):

X. Guo ◽

P. He ◽

K. Xu ◽

P. Y. Chen ◽

B. Chen ◽

...

Keyword(s):

Weld Metal ◽

Microstructural Evolution ◽

Heat Dissipation ◽

Eutectic Reaction ◽

Linear Chain ◽

Liquation Cracking ◽

Leading Role ◽

Melted Zone ◽

Constitutional Liquation ◽

Multipass Weld

AbstractThe microstructure of ERNiCrFe-13 multipass weld metal has been shown to contain Laves/γ or σ/γ eutectic constituents that can increase susceptibility to solidification and weld metal liquation cracking resulting from the low eutectic reaction temperature. Under poor heat dissipation conditions such as on the edge of large thickness welded components, a partially melted zone (PMZ) may form in the weld metal during multipass welding. The microstructural evolution and liquation cracking susceptibility of this PMZ in ERNiCrFe-13 multipass welds have received little attention. In the present study, a tungsten inert gas (TIG) refusion process is used to simulate a thermal cycle with a long elevated temperature dwell time in order to investigate the microstructural evolution and liquation cracking in the weld metal PMZ. The results show that the eutectic microstructures in the PMZ evolve into three eutectic morphologies after TIG refusion, including long linear chains extending perpendicular to the boundary between the refusion zone and PMZ, skeletal structures, and fine lamellar networks. This evolution contributes to constitutional liquation occurring at the γ/Laves and γ/σ interface. Nb and Mo play a leading role in the constitutional liquation of γ/Laves and γ/σ eutectic microstructures, respectively. Liquation cracking in the PMZ is shown to occur along the linear chain grain boundaries resulting from constitutional liquation.

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UNIFLUX VCM 125

Alloy Digest ◽

10.31399/asm.ad.sa0340 ◽

1978 ◽

Vol 27 (1) ◽

Keyword(s):

Carbon Dioxide ◽

Fracture Toughness ◽

Weld Metal ◽

Heat Treating ◽

Carbon Steels ◽

Low Alloy Steels ◽

Electrode Wire ◽

Molybdenum Steel ◽

Alloy Steels ◽

Welding Electrode

Abstract UNIFLUX VCM 125 is a continuous flux-cored welding electrode (wire) that is used to deposit 1 1/4% chromium-1/2% molybdenum steel for which it was developed. Welding is protected by a shielding atmosphere of 100% carbon dioxide. This electrode also may be used to weld other low-alloy steels and carbon steels; however, the weld metal may differ somewhat from 1 1/4% chromium-1/2% molybdenum because of weld-metal dilution. When Uniflux VCM 125 is used to weld 1 1/4% chromium-1/2% molybdenum steel, it provides 95,000 psi tensile strength at 70 F and 24 foot-pounds Charpy V-notch impact at 40 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-340. Producer or source: Unicore Inc., United Nuclear Corporation.

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Microstructural evolution and mechanical integrity relationship of dissimilar metal welding between 2205 duplex stainless steel and composite bimetallic plates

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211003615 ◽

2021 ◽

pp. 095440622110036

Author(s):

Changqing Ye ◽

Weiguo Zhai ◽

Guangyao Lu ◽

Qingsong Liu ◽

Liang Ni ◽

...

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Weld Metal ◽

Duplex Stainless Steel ◽

Intergranular Corrosion ◽

Thermal Cycle ◽

Filler Metal ◽

2205 Duplex Stainless Steel ◽

Welding Thermal Cycle ◽

Intergranular Corrosion Resistance

In this paper, shielded metal arc welding on the dissimilar joint between 2205 duplex stainless steel and composite bimetallic plates (304 L stainless steel/10CrNi3MoV steel) with a filler metal E2209 was performed. Furthermore, the microstructure, phase, mechanical properties and intergranular corrosion resistance of the joints were investigated and element distributions of the interfaces were characterized. The results show that austenite transformed to ferrite under the influence of welding thermal cycle, and then a large amount of ferrite appeared in heat affected zone (HAZ) of 2205 duplex stainless steel. Coarse bainite grains were formed in HAZ of the 10CrNi3MoV steel near the fusion line with high temperature welding thermal cycle. Fine granular bainite was also generated in HAZ of 10CrNi3MoV steel due to the relatively short exposure time to the active temperature of grain growth. Local peak temperature near the base 10CrNi3MoV steel was still high enough to recrystallize the 10CrNi3MoV steel to form partial-recrystallization HAZ due to phase change. The filler metal was compatible with the three kinds of base materials. The thickness of the elemental diffusion interfaces layers was about 100 µm. The maximum microhardness value was obtained in the HAZ of 2205 duplex stainless steel (287 ± 14 HV), and the minimum one appeared in HAZ of SS304L (213 ± 5 HV). The maximum tensile strength of the welded joint was about 670 ± 6 MPa, and the tensile specimens fractured in ductile at matrix of the composite bimetallic plates. The impact energy of the weld metal and HAZ of the 10CrNi3MoV steel tested at –20 °C were 274 ± 6 J and 308 ± 5 J, respectively. Moreover, the intergranular corrosion resistance of the weldment including 304 L stainless steel, weld metal, HAZs and 2205 duplex stainless steel was in good agreement with the functional design requirements of materials corrosion resistance.

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