Finite elements prediction of thermal stresses in work roll of hot rolling mills

Abstract

A simplified numerical approach based on finite elements to compute thermal stresses occurring in work roll of hot rolling mills is here proposed. To decrease both the complexity of the analysis and the computational effort, this approach implements a plane finite element model of the work roll alone, loaded on its surface by the rotating thermal actions due to the cyclic sequence of the conductive heating caused by the contact with hot strip and cooling provided by water jets. Results from thermal analysis are preliminary compared to an analytical solution available in the literature and then applied as thermal input in the subsequent mechanical finite elements simulations, which provide thermal stress in the work roll and the elastic-plastic evolution of elements, close to the work roll surface

A Semi-Analytical Finite Element Approach in Machine Design of Axisymmetric Structures

“…An example could be a rotating cylinder under imposed temperature and fluxes, which has been used as a simplified model for estimating the non-uniform transient temperature in a work roll of a hot rolling mill (Benasciutti, 2010a). Numerical FE modelling may be still very complex, even using a simplified twodimensional modelling with a commercial FE code, as transient analysis needs large computational times and computer resources.…”

“…In a thermal analysis, the elements used are of "truss type" (onedimensional) and the degree of freedom in each node is temperature. The theory of different types of harmonic finite element for thermal analysis have been formulated for a plane thermal analysis: two-node elements (with one or two Gauss points) having linear shape functions, three-node elements (with two or four Gauss points) having quadratic shape functions (Benasciutti et al, 2010b(Benasciutti et al, , 2011). An example is shown in Fig.…”

“…8), which has been used as a simplified model for a work roll of a hot rolling mill (Benasciutti et al, 2010a). In the simplified approach, only work roll (without the strip) was modelled in a two-dimensional analysis; thermal loadings are applied on the surface, to simulate strip heating and water jet cooling.…”

“…As an order of magnitude, the simulation required about 3 days of simulation. It is worth mentioning how results of thermal analysis have been validated, see (Benasciutti et al, 2010b), by an analytical solution for the stationary temperature distribution (Patula, 1981). Other details on FE model and simulation parameters can be found in (Benasciutti 2010a Initial temperature of work roll Table 2.…”

Characteristics of the thermal fatigue resistance for 3.1C, 0.8Si, 0.9Mn, 1.7Cr, 4.5Ni and 0.3Mo ICDP cast iron roll at 600 °C

“…), thermal, microstructural properties as well as oxidation resistance should be engineered. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Several research works related to thermal fatigue resistance of die materials (i.e. steels, cast irons) were carried out where reasons for initiation and growth of cracks at hot working dies (forging, die casting) [17][18][19][20][21][22][23][24][25][26][27][28][29][30] and hot working rolls [3][4][5][6]9,[31][32][33][34] were investigated using various laboratory tests.…”