| OCR Text |
Show In order to understand the relation between the "skid mark" and the skid position, Figure 7 shows the radiative heat flux on the lower surface of the slab without any loss, when Tg profile is the type A and type C and mean temperature of gas is 1550K. The horizontal axis shows the position of the skid beam. The vertical axis shows the heat flux into the lower surface of the slab without the heat loss by radiation and cooled water. This figure tells ; 1. The position of the skid beam does not affect the lowest value of the heat flux , but the highest value does. 2. The long distance between the skid beam and the walking beam at the higher temperature side makes the highest value of the heat flux larger. 3. The large deviation of the temperature profile of gas causes the large deviation of the heat flux. As a result, we can say that the skid beam should be located at the position to make the highest heat flux minimum in order to minimize the "skid mark", 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Skid position [m] O : k=0.12[m-1] • : k=0.16[m-1] A : k=0.20[m-l] Tg type A Tg typeB Tg typeC Figure 6 "Skid mark" in various skid position £J 300000 ^ 250000 2, 200000 x 150000 "= 100000 0) X £J 300000 ^ 250000 5, 200000 x 150000 U= 100000 CO I 0.5 1 1.5 Skid position [m] 0 0.5 1 1.5 2 Skid position [m] Figure 7 Radiative heat flux on the lower surface of the slab without any loss when the mean gas temperature is 1550K for example 1.48m is the best skid position in the case of type C, because the deviation of heat flux into the slab surface is minimized in such a condition. And it follows from what has been said that the temperature profile of gas is one of the most important factor to determine the position of the skid beam. 4.3 With skid shift Optimization of the skid shift length and that of position of the initial skid and the second skid is described here. As the "skid mark" does not depend on the absorption r ^ |
