Evaluation of cracking resistance of DC casting high strength aluminum ingots

Paramatmuni, Rohit K.; Chang, Keh‐Minn; Kang, Bruce S.; Liu, Xingbo

doi:10.1016/j.msea.2004.02.026

Cited by 32 publications

(8 citation statements)

References 8 publications

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“…They suddenly bend afterward and move upward to the head of the billet.) [20,21,38] In the center of the 200-mm billet, the situation becomes critical after 200 seconds when the largest component of principal stresses reaches its maximum value (71.5 MPa for the standard case).…”

Section: Discussionmentioning

confidence: 99%

Cold Cracking Development in AA7050 Direct Chill–Cast Billets under Various Casting Conditions

Lalpoor

Eskin

Katgerman

2010

Metall Mater Trans A

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Cold cracking is a potentially catastrophic phenomenon in direct chill (DC) casting of 7xxx series aluminum alloys that leads to safety hazards and loss of production. The relatively low thermal conductivity and wide solidification temperature range in these alloys results in accumulation of residual thermal stress under nonuniform cooling conditions of the billets. In addition, such alloys show a severe loss in ductility below a critical temperature of 573 K (300°C). This brittleness along with high stress concentration at the tips of voids and microcracks can lead to catastrophic failure. Casting process parameters affect the magnitude and distribution of stresses in the billet and increase the susceptibility of the material to cold cracking. In order to investigate the effect of casting process parameters such as casting speed, billet size, and water flow rate, thermomechanical simulations were applied using ALSIM5 casting simulation software. Among the studied casting process parameters, the increased billet size and high casting speed resulted in the most dramatic increase in residual stress level. Critical crack sizes that led to catastrophic failure were also calculated and are reported against process parameters.

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Section: Discussionmentioning

confidence: 99%

Cold Cracking Development in AA7050 Direct Chill–Cast Billets under Various Casting Conditions

Lalpoor

Eskin

Katgerman

2010

Metall Mater Trans A

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“…According to fracture mechanics, however, large thumbnail cracks with the critical length of 14.1 mm can catastrophically propagate in the tensile stress field and result in J-cracks. [7,8,26] (This occurs mainly in slabs where the stress state in the vicinity of the narrow side remains tensile. [23] ) Apparently such cracks do not get the chance to reach such lengths during the short period of the tensile stress occurrence in billets.…”

Section: Discussionmentioning

confidence: 99%

Cold-Cracking Assessment in AA7050 Billets during Direct-Chill Casting by Thermomechanical Simulation of Residual Thermal Stresses and Application of Fracture Mechanics

Lalpoor

Eskin

Katgerman

2009

Metall Mater Trans A

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Thermally induced strains and stresses developed during direct-chill (DC) semicontinuous casting of high strength aluminum alloys can result in formation of micro-cracks in different locations of the billet. Rapid propagation of such micro-cracks in tensile thermal stress fields can lead to catastrophic failure of ingots in the solid state called cold cracking. Numerical models can simulate the thermomechanical behavior of an ingot during casting and after solidification and reveal the critical cooling conditions that result in catastrophic failure, provided that the constitutive parameters of the material represent genuine as-cast properties. Application of fracture mechanics, on the other hand, can help to derive the critical crack length leading to failure. In the present research work, the state of residual thermal stresses was determined in an AA7050 billet during DC casting by means of ALSIM5. Simulation results showed that in the steady-state conditions, large compressive stresses form near the surface of the billet in the circumferential direction, whereas in the center, the stresses are tensile in all directions. Magnitudes of von Mises effective stresses, the largest component of principal stresses and the fracture mechanics concepts, were then applied to investigate the crack susceptibility of the billet.

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“…So the constituents must be controlled in the process of solidification. The effects of cooling rate and alloy composition on the phase formation during the process solidification have been reported in many previous studies [11,12]. However, the reports about the effects of electromagnetic field on the constituents are limited.…”

Section: Introductionmentioning

confidence: 97%

Effect of low frequency electromagnetic field on the constituents of a new super high strength aluminum alloy

Zuo

Chen

Dong

et al. 2005

Journal of Alloys and Compounds

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Evaluation of cracking resistance of DC casting high strength aluminum ingots

Cited by 32 publications

References 8 publications

Cold Cracking Development in AA7050 Direct Chill–Cast Billets under Various Casting Conditions

Cold Cracking Development in AA7050 Direct Chill–Cast Billets under Various Casting Conditions

Cold-Cracking Assessment in AA7050 Billets during Direct-Chill Casting by Thermomechanical Simulation of Residual Thermal Stresses and Application of Fracture Mechanics

Effect of low frequency electromagnetic field on the constituents of a new super high strength aluminum alloy

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