| With the development of cold rolling technologies,high-speed rolling has become the trend of modern cold tandem mill.In the high-speed cold rolling process,deformation heat,friction heat generated between the strip and the rolls in unit time will greatly increase,which gives a new challenge to the cooling and lubrication process.Though cold-rolling at room temperature,the deformation heat and friction heat can increase the rolling temperature,especially in high-speed rolling process.When the rolling temperature is too high,on the one hand,it will be harmful to the rolls,such as surface cracks induced;on the other hand,it will lead to lubricating oil invalid.Thus it has a bad effect on the products.So cooling process of roller is necessary.Cooling and lubrication process are two important parts of the cold rolling process,which play important roles in the process of cold-rolled strip steels.In the production process of stainless steel using Sendzimir mill,lubricant oil film rupture,chromatic aberration and other complex problems are prone to occur.Oil film rupture is mainly due to oil film strength and temperature are too high,and chromatic aberration is mainly induced by uneven rolling oil spray.To solve these problems,the research of roll cooling characteristics are involved,including the rolling oil spraying uniformity,cooling intensity,the model of heat transfer coefficient and roll temperature field.In this research,appropriate working condition of nozzle spray pressure and rolling oil injection amount are selected through lots of simulation and experiment researches under the condition of rolling oil and nozzle has been given,which provided a theoretical basis to solve chromatic aberration problem and so on.The main contents are as follows:(1)In order to investigate the uniformity of the nozzle and the rolling oil cooling intensity,injection device simulation platform was established.The nozzle used on-site mill was simulated according to the site of nozzle arrangement and working conditions,to determine whether the working condition is reasonable.(2)The effect of spray pressure,spray distance,spray angle and nozzle spacing on lateral distribution uniformity of rolling oil have been analyzed.The results show that rolling oil cooling intensity has a relation with the size of the rolling oil flow,and the size of the injection pressure directly determined the amount of flow.Spray distance has a great influence on the spray range with the increasing of spraying distance.To obtain more evenly rolling oil injection distribution uniformly,nozzle spacing should be increased accordingly.When the spray distance is 12 cm,spray angle is 15°,rolling oil injection distribution is more uniform.(3)The influences of spray distance,injection pressure,and the temperature of rolling oil on the heat transfer coefficient were studied.Rolling oil heat exchange capacity calculation model was obtained,and it can provide a condition to calculate roll temperature.(4)The heat transfer coefficient model was established,it mainly including the heat exchange between the rolled pieces and the rolls,rolling oil and rolls,rolls contact,as well as air and rolls.(5)Dividing the roll surface into different areas to calculate the heat exchange between rolling oil and environment during the rotation of rolls.Based on the finite element software ANSYS platform,a finite element analysis software to calculate the roll temperature field has been developed and the calculated results are in high agreement with the measured data.(6)In the axial direction of roller,the tiny difference of rolling oil flow density leads to the axial cooling intensity,thus the different temperature field distribution has been obtained.(7)Through large amounts of simulation,the roll initial temperature,cooling intensity,rolling speed,the strip temperature on the law of the roll temperature field were given. |
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