【正文】 BSPLIN, ,P51X FLST,2,2,3 FITEM,2,2 FITEM,2,3 FLST,3,2,3 FITEM,3,2 FITEM,3,3 BSPLIN, ,P51X FLST,3,2,3 FITEM,3,3 FITEM,3,4 BSPLIN, ,P51X FLST,3,2,3 FITEM,3,4 FITEM,3,5 BSPLIN, ,P51X FLST,3,2,3 FITEM,3,5 FITEM,3,6 BSPLIN, ,P51X FLST,3,2,3 FITEM,3,6 FITEM,3,7 BSPLIN, ,P51X FLST,3,2,3 FITEM,3,7 FITEM,3,8 BSPLIN, ,P51X FLST,3,2,3 FITEM,3,1 FITEM,3,8 BSPLIN, ,P51X FLST,2,8,4 FITEM,2,1 FITEM,2,2 FITEM,2,3 FITEM,2,4 FITEM,2,5 FITEM,2,6 FITEM,2,7 FITEM,2,8 AL,P51X FLST,2,1,5,ORDE,1 FITEM,2,1 FLST,8,2,3 FITEM,8,1 FITEM,8,8 VROTAT,P51X, , , , , ,P51X, ,360, , FLST,2,4,6,ORDE,2 FITEM,2,1 FITEM,2,4 VADD,P51X VPLOT WPOFF,342,0,0 CSYS,4 PCIRC,210,0,120,240,WPOFF,342,0,0 CSYS,4 K,111,640,275,0,K,112,640,275,0, K,113,540,245,0,K,114,540,245,0, FLST,3,3,3 FITEM,3,111 FITEM,3,113 FITEM,3,27 BSPLIN, ,P51X, , , , ,FLST,3,3,3 FITEM,3,112 FITEM,3,114 FITEM,3,28 BSPLIN, ,P51X, , , , ,LSTR, 111, 112 LSTR, 27, 28 FLST,2,4,4 FITEM,2,56 FITEM,2,59 FITEM,2,57 FITEM,2,58 AL,P51X FLST,2,2,5,ORDE,2 FITEM,2,1 FITEM,2,9 AADD,P51X VOFFST,17,500, , VOFFST,17,500, ,VSBV, 5, 2 VSBV, 3, 1 K,222,110,0,260, K,223,0, K,224,0, K,225,630,0,0, K,228,110,0,400, K,229,110,0,400,K,226,700,0,400,K,227,700,0,400,K,230,110,0,260,LSTR, 230, 229 LSTR, 229, 226 LSTR, 226, 227 LSTR, 227, 228 LSTR, 228, 222 LSTR, 230, 224 LSTR, 222, 223 FLST,3,3,3 FITEM,3,223 FITEM,3,224 FITEM,3,225 BSPLIN, ,P51X LDELE, 54 LARC, 223, 224, 225 FLST,2,8,4 FITEM,2,47 FITEM,2,46 FITEM,2,41 FITEM,2,40 FITEM,2,39 FITEM,2,52 FITEM,2,54 FITEM,2,53 AL,P51X APLOT VOFFST,1,500, , VOFFST,1,500, ,VSBV, 2, 1 VSBV, 4, 3 WPRO, CYL4,H,0,R !*定義參數(shù)方程VOFFST,1,500, ,VOFFST,1,500, , VSBV, 1, 3 VSBV, 4, 2 ET,1,SOLID92 !*選擇單元類型ESIZE,30,0, !*設置單元尺寸MSHAPE,1,3D !*劃分網(wǎng)格MSHKEY,0 CM,_Y,VOLU VSEL, , , , 1 CM,_Y1,VOLU CHKMSH,39。 is surface tractions。 c is specific heat。 the laminar cooling section, and the cooling water spray system with low pressure and high flowrate in the nterstands, which are used to control the increasing temperature because of the plastic deformation. An FE analysis model for a single pass rolling is first built, in which the interstand tension stress is put on the stock to realize the whole rolling patibility. The stock is meshed using the quadrilateral element with four nodes and the total number of elements is 1350. The stock material is SS400 and the initial thickness is 45. 9 mm. The rolling schedule in the simulation is shown in Table 1. Other initial data such as the temperature and the grain size are obtained from the simulated results of 2050 mm roughing mill.2 Results and DiscussionThe FE analysis of the actual rolling process is done using the FE model described above. The temperature and the austenite grain size distributions predicted by the present FE model are demonstrated in Fig. 3, which contains the temperature changes on the surface and at the center of the strip as well as the measured results.From the temperature curves in Fig it can be seen that the twice temperature great drops before rolling are due to the descaling water action. On the F1 stand rolling, the strip surface temperature drops rapidly in the roll gaps and thereafter increases slowly because of the relatively cold roll. The center temperature of the stock increases to some extent in the deformation region because of the heat generation from plastic work and decreases slowly in the interstands because of the heat loss ,of convection and radiation. Moreover, the large temperature drops also occur in the interstand owing to the low pressure cooling water. After rolling, the strip passes through the laminar cooling section and the temperature rapidly decreases from about 900 39。C and the temperature before coiler was measured to be 560 C. The predicted temperatures agree well with the measured temperatures.From Fig 3, it is found that the austenite grain size is refined from an initial size of at the center and at the surface to and , respectively. The maximum change of the grain size exists at the stand F1, and it subsequently decreases slowly by actions of deformation refinement. The final austenite grain size grade measured is about 8 ( ). Thus, the predicted grain size of austenite is in good agreement with the measured result.Fig. 4 shows the simulated distributions of DRX and SRX volume fractions in hot strip continuous rolling process. In the hot rolling process, the steel is deformed using higher strain rates at considerably lower temperature, but the plastic strains at the first three passes are greater than the critical strains, and the DRX fraction at the stand F1 is %. Therefore,DRX still has a great effect on the grain size and cannot be ignored. During the time intervals among the first four finishing stands, full SRX can be obtained but some fractions are smaller than 1,while, the remanent softening can be plete by MRX according to the calculation procedures described above.When the stock passes through the runout table,the austenite microstructure of the steel is gradually transformed into ferrite and pearlite with decreasing the temperature. The predicted ferrite grain size after transformation is presented in with a span of to . shows the actual metallograph of ferrite and pearlite,and the measured ferrite grain size is about . Thus, the calculated grain size of fer