Thermal and mechanical behavior of copper molds during thin-slab casting (I): Plant trial and mathematical modeling

Abstract

Three-dimensional (3-D) finite-element thermal-stress models have been developed to predict temperature, distortion, and residual stress in the mold of continuous casters of thin steel slabs, comparing both funnel-shaped and parallel molds. The mold shape and high casting speed leads to higher mold temperatures and shorter mold life than in conventional slab casters. This study investigates heat flux and the effects of mold shape on distortion and cracking of the thin-slab mold. In Part I of this twopart article, mold wall temperatures measured in the plant were analyzed to determine the corresponding heat-flux profiles in thin-slab molds. This data was then used in an elastic-visco-plastic analysis to investigate the deformation of the molds in service for the two different mold shapes. The model predictions of temperature and distortion during operation match plant observations. During operation, the hot-face temperature reaches 580 ЊC and heat flux varies from 7 to 4.5 MW/m 2 when casting at 3.6 m/min. The copper plates bend toward the steel, with a maximum outward distortion of about 0.3 mm. This occurs just above the center of the wide faces and is smaller than the distortion of a conventional slab mold. JOONG KIL PARK, Graduate Student, and INDIRA V. mity of heat transfer, with resulting improvements in mold SAMARASEKERA, Professor, are with the Department of Metals and life and reduction in sticking corner breakouts. Materials Engineering, University of British Columbia, Vancouver, Ozgu [4] instrumented a slab mold to measure a wide range BC, Canada V6T 1Z4. Contact

Heat Transfer in Funnel-mould Casting: Effect of Plate Thickness

“…Heat transfer in funnel moulds has been investigated in only a few previous studies, examining heat flux profiles, 1) mould distortion and cracking, [1][2][3] phenomena in the steel/flux interface, [4][5][6] and fluid flow coupled with solidification heat transfer. 7) Heat flux tends to be higher in thin-slab casting than in conventional billet or slab casting, which is attributed to the higher casting speeds.…”

“…7) Heat flux tends to be higher in thin-slab casting than in conventional billet or slab casting, which is attributed to the higher casting speeds. 1) Computational models can reveal insights into mould heat transfer, so long as they have been calibrated with plant data. Recent modelling studies of billet casting, which use thermocouple measurements and inverse heat transfer calculations to determine the heat flux profile, have shown that mould hot-face temperature increases with increasing mould plate thickness and casting speed.…”

Optimization design of wide face water slots for medium-thick slab casting mold

“…where T is the temperature, ρ, λ and C p are the density, thermal conductivity and specific heat, respectively, which can be obtained in Table 2, and ω is the source of heat [1] , which is 0 in this study. The axes of x, y and z in the coordinate system are parallel to the length, the height and the width of copper plate, respectively, and their coordinate origin is at the midpoint of the symmetry plane in the half copper plate.…”

“…In order to assess the role of various process parameters impacting mold life, O'Connor and Dantzig developed a finite-element model to calculate the thermo-mechanical state in the mold and casting slab [4] . Thomas and Park et al applied a threedimensional finite-element model to predict temperature, thermal distortion, thermal stress and hot face cracks in a funnel shaped mold for casting thin-slab [1,[5][6][7] . Santillana et al applied a one-dimensional finite-element model to modify the 3D model, and predict temperatures for copper plates with different thicknesses [8,9] .…”

“…His main research fields cover the numerical simulation of metal solidification and in-situ observation on grain growth by synchrotron radiation imaging. C ontinuous casting is the most widely used casting method due to its significant superiority in the processing of steels, such as high productivity, good quality and associated savings in capital cost, energy and man power [1,2] . The mold is the most critical component of a continuous casting.…”