Modeling of ingot distortions during direct chill casting of aluminum alloys

Drezet, Jean‐Marie; Rappaz, M.

doi:10.1007/bf02663872

Cited by 86 publications

(96 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thermomechanical modeling tools to design and optimize the DC casting process have been developed at several industry and university consortia (such as VirCAST [97] and EMPACT [37] in Europe and SECAT [98] in the United States) using FE packages such as MARC [99] (at CORUS, Netherlands and Péchiney, France [37] ), ABAQUS [100] (at EPFL-Lausanne, Switzerland [14,44] ), and ALSIM [101] /ALSPEN [102,103] (at Institute for Energy Technology, and Hydro Aluminum, Norway [104] ). National laboratories in the United States (Albany Research Center, Oregon, Argonne National Laboratory, Illinois, and Oak Ridge National Laboratory, Tennessee) and at the University of Kentucky (Lexington, KY) have also collaborated recently to develop mathematical models to study ingot stress crack formation and butt deformation [105] and to reduce aluminum ingot scrap.…”

Section: Optimization Of Water Coolingmentioning

confidence: 99%

“…To prevent this effect, called ingot rolling face "pull-in," most high-aspect-ratio molds are designed with convex shape. [14] This article was undertaken to compare and contrast the heat-transfer phenomena in continuous casting of steel and (a) (b) Fig. 2-Schematic of cooling processes, for (a) continuous casting of steel [15] and (b) DC casting of aluminum [5] .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The use of water cooling during the continuous casting of steel and aluminum alloys

Sengupta

Thomas

Wells

2005

Metall Mater Trans A

110

View full text Add to dashboard Cite

In both continuous casting of steel slabs and direct chill (DC) casting of aluminum alloy ingots, water is used to cool the mold in the initial stages of solidification, and then below the mold, where it is in direct contact with the newly solidified surface of the metal. Water cooling affects the product quality by (1) controlling the heat removal rate that creates and cools the solid shell and (2) generating thermal stresses and strains inside the solidified metal. This work reviews the current stateof-the-art in water cooling for both processes, and draws insights by comparing and contrasting the different practices used in each process. The heat extraction coefficient during secondary cooling depends greatly on the surface temperature of the ingot, as represented by boiling water-cooling curves. Thus, the heat extraction rate varies dramatically with time, as the slab/ingot surface temperature changes. Sudden fluctuations in the temperature gradients within the solidifying metal cause thermal stresses, which often lead to cracks, especially near the solidification front, where even small tensile stresses can form hot tears. Hence, a tight control of spray cooling for steel, and practices such as CO 2 injection/pulse water cooling for aluminum, are now used to avoid sudden changes in the strand surface temperature. The goal in each process is to match the rate of heat removal at the surface with the internal supply of latent and sensible heat, in order to lower the metal surface temperature monotonically, until cooling is complete.

show abstract

Section: Optimization Of Water Coolingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The use of water cooling during the continuous casting of steel and aluminum alloys

Sengupta

Thomas

Wells

2005

Metall Mater Trans A

110

View full text Add to dashboard Cite

show abstract

“…Further details on the FE model of casting can be found in [1,2,8,9,20]. Figure 4 shows the computed temperature distribution and extension of the mushy zone (solid volume fractions between 0.0 and 1.0) in the absence of a wiper (left) and when a wiper is used (right).…”

Section: Thermomechanical Model Of Castingmentioning

confidence: 99%

“…The computation of stresses during DC casting of aluminum alloys has been the scope of several studies since the late 90's [2][3][4][5][6][7][8][9][10] and is a well established technique nowadays. Many numerical models have allowed researchers to compute the ingot distortions and the associated residual stresses.…”

Section: Introductionmentioning

confidence: 99%

“…Residual stress measurements have been carried out at the neutron diffractometer SALSA at ILL-Grenoble, France [21]. The goal of the present work is:• to quantify the level of as-cast residual stresses in the foot of the slab, • to compare the measured residual stresses with those predicted by the DC casting finite element (FE) model developed by Drezet et al [1,2], …”

mentioning

confidence: 99%

See 1 more Smart Citation

Neutron Diffraction Measurement of As-Cast Residual Stresses in Aa7050 Rolling Plate Ingots: Influence of A Wiper

et al. 2014

View full text Add to dashboard Cite

During casting, thermally induced deformations give birth to ingot distortions and residual stresses. For some high strength alloys, ingot cracking can happen during casting per se or during cooling down. Ingot distortions such as rolling face pull-in, but curl and but swell are rather easy to quantify as opposed to internal stresses. As aluminium is rather transparent to neutrons, residual stress measurements using neutron diffraction appeared to be a good way to validate the thermomechanical models aimed at simulating the stress build-up during casting. This technique has been applied to DC cast AA7050 rolling plate ingots with special attention to the stress generation in the transient start-up phase, i.e. in the foot of the ingot. Additional results using the hole drilling method complement the measurements. The measured stress distributions are compared with the results of a numerical model of DC casting for ingots cast with and without a wiper. I IntroductionIn the fabrication of aluminum rolling plates, the first step is the semi-continuous casting of a rectangular ingot. The most commonly used process is known as direct chill (DC) casting [1]. This process gives rise to large thermally induced strains that lead to several types of casting defects (distortions, cold cracks, porosity, solidification cracking, etc.). During casting, thermally induced stresses are partially relieved by permanent deformation. When these residual stresses overcome the deformation limit of the alloy, cracks are generated either during solidification (hot tears) or during cooling (cold cracks). The formation of these cracks results in rejection of the cast part. Furthermore, thermally induced stresses can cause downstream processing issues during the sawing stage prior to rolling. For large ingot formats and high strength alloys, sawing becomes a delicate task owing to the risk of saw pinching or crack initiation ahead of the saw. The use of wipers during casting largely reduces the level of as-cast stresses.The computation of stresses during DC casting of aluminum alloys has been the scope of several studies since the late 90's [2-10] and is a well established technique nowadays. Many numerical models have allowed researchers to compute the ingot distortions and the associated residual stresses. The validation of these models was often done by comparing the computed and measured ingot distortions, e.g. the butt-curl [8] and the rolling face pull-in for rolling sheet ingots produced by DC [9] or electromagnetic casting [11].Validation against the computed room-temperature residual stresses is limited simply owing to the difficulty of measuring the internal strains and the high variability in the measurements. While some measurements are available for quenching [12] or welding [13], they remain rare, uncertain and usually are limited to one or two components of the stress tensor, and to the skin of round billets for as-cast materials [14][15]. In contrast to destructive methods for measuring residual stresses (hole-drilli...

show abstract