On the Origin of Weld Solidification Cracking

Cross, C. E.

doi:10.1007/3-540-27460-x_1

Cited by 93 publications

(51 citation statements)

References 9 publications

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“…When a melt film is still present between the two solidification fronts, due to the localization of high tensile stress, the initiation of solidification cracks is expected (see Figure 18). The risk of formation of the solidification cracks continues until the temperature reaches 988 °C, due to low melting phases such as Fe-S [31]. …”

Section: Discussionmentioning

confidence: 99%

Numerical Simulation on the Origin of Solidification Cracking in Laser Welded Thick-Walled Structures

Bakir

Artinov

Gumenyuk

et al. 2018

Metals

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Abstract:One of the main factors affecting the use of lasers in the industry for welding thick structures is the process accompanying solidification cracks. These cracks mostly occurring along the welding direction in the welding center, and strongly affect the safety of the welded components. In the present study, to obtain a better understanding of the relation between the weld pool geometry, the stress distribution and the solidification cracking, a three-dimensional computational fluid dynamic (CFD) model was combined with a thermo-mechanical model. The CFD model was employed to analyze the flow of the molten metal in the weld pool during the laser beam welding process. The weld pool geometry estimated from the CFD model was used as a heat source in the thermal model to calculate the temperature field and the stress development and distributions. The CFD results showed a bulging region in the middle depth of the weld and two narrowing areas separating the bulging region from the top and bottom surface. The thermo-mechanical simulations showed a concentration of tension stresses, transversally and vertically, directly after the solidification during cooling in the region of the solidification cracking.

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Section: Discussionmentioning

confidence: 99%

Numerical Simulation on the Origin of Solidification Cracking in Laser Welded Thick-Walled Structures

Bakir

Artinov

Gumenyuk

et al. 2018

Metals

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“…Determining the coherency and coalescence points of an alloy is of great importance for characterizing the semisolid rheological properties with applications in several solidification-related domains such as solidification cracking modeling [40][41][42][43][44][45] and stir casting process understanding [46][47][48]. Experimental measurement of these two points could be implemented in the corresponding models when used in combination with casting simulations.…”

Section: Discussionmentioning

confidence: 99%

Investigating surface roughness of ZE41 magnesium alloy cast by low-pressure sand casting process

Sanitas

Coniglio

Bedel

et al. 2017

Int J Adv Manuf Technol

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To cite this version:A. Sanitas, N. Coniglio, M. Bedel, M. El Mansori. Investigating surface roughness of ZE41 magnesium alloy cast by low-pressure sand casting process. International Journal of Advanced Manufacturing Technology, Springer Verlag, 2017, 92 (5-8), pp.1883-1891. 10.1007 Investigating surface roughness of ZE41 magnesium alloy cast by low-pressure sand casting processAbstract The sand mold 3D printing technologies enable the manufacturing of molds with great dimensional accuracy. However, the roughness of as-cast components is higher when cast in a 3D printed mold rather than in a traditional sand mold. Coating the inner cavity is an efficient solution but can be costly and, in the narrowest cavities, not achievable. Finding a procedure to reduce the as-cast roughness without coating would ease the casting procedures. In the present work, surface analysis of ZE41 magnesium alloy is presented after being cast in 3D printed furan sand molds without coating using the low-pressure casting process. The molten metal temperature was measured during casting at different positions along the cast cavity. The as-cast surface roughness was correlated to the molten metal temperature and solid fraction at the time of contact against the sand mold surface.

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“…18 This Modified Crack Theory further tries to identify the mechanisms involved with solidification cracking. Both of these theories work to better understand the mechanisms the lead to the formation of hot cracks.…”

Section: Types Of Cracking In Ni-based Super Alloys 121 Hot Crackingmentioning

confidence: 99%

Characterization of Inconel 718: Using the Gleeble and Varestraint Testing Methods to Determine the Weldability of Inconel 718

Knock¹

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CHARACTERIZATION OF INCONEL 718: USING THE GLEEBLE AND VARESTRAINT TESTING METHODS TO DETERMINE THE WELDABILITY OF INCONEL 718Nickel based superalloys were developed to withstand the severe thermal and mechanical environment associated with rocket propulsion systems and jet engines. In many alloy systems the strength of a component rapidly deteriorates as the operating temperature increases. Nickel based superalloys, however, retain strength over a range of temperatures which includes the operating range for many propulsion systems. This improved performance is accomplished by a combination of solid-solution strengthening, precipitation strengthening and grain-boundary strengthening. Furthermore, super-alloy systems are designed for ease of fabrication, to include machining, welding and heat treating. Inconel 718 was developed to overcome problems with post-weld cracking that were common in precipitation hardened nickel based superalloys strengthened by γ'. Inconel 718 is strengthened by γ'' and is less sensitive to cracking during post-weld thermal treatment. However, in some cases, compositional changes which improved the behavior of these alloys during stress relief actually led to greater difficulty during the joining process. Varestraint samples were prepared as per standard preparation techniques and tested longitudinally with a GTAW. At a predetermined location a strain was applied perpendicular to iv weld direction. The applied strain varied from 0.25%, 0.5%, 1.0%, 2.0%, and 4.0%. The Inconel 718 yielded a maximum crack length of 0.6 mm with a saturation strain of 2.0%. Both the total crack length and the number of cracks did not have a saturation strain.Gleeble samples were prepared from rod stock and tested with standard methodology to determine the characteristic temperatures: nil ductility, nil strength, and ductility recovery temperature of Inconel 718. The samples were tested at various pull temperatures on-heating until the nil strength temperature then tested on-cooling with the nil strength temperature acting as the peak temperature. The nil strength temperature was 2273°F, nil ductility temperature was 2182°F, and the ductility recovery temperature was 1925°F.Both the Varestraint and Gleeble results were compared with relevant literature to determine the weldability of the Inconel 718. Four criteria were used to determine the weldability of Inconel 718 and in three of the four tests; the Inconel 718 had equal to or greater weldability than the compared materials. In the fourth test, the Inconel 718 demonstrated lower weldability than the compared alloy systems, however, Inconel 718 operates in different conditions specifically, the high temperature and pressure conditions mentioned above.

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On the Origin of Weld Solidification Cracking

Cited by 93 publications

References 9 publications

Numerical Simulation on the Origin of Solidification Cracking in Laser Welded Thick-Walled Structures

Numerical Simulation on the Origin of Solidification Cracking in Laser Welded Thick-Walled Structures

Investigating surface roughness of ZE41 magnesium alloy cast by low-pressure sand casting process

Characterization of Inconel 718: Using the Gleeble and Varestraint Testing Methods to Determine the Weldability of Inconel 718

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