辽宁科技大学本科生毕业设计 第 1页外文原文：Rolling conditions in hot strip mills and their influence on the performance of work rollsSummary.The mechanical rolling conditions in hot strip mills are precisely defined by variables,which are taken directly from the rolling scheduleseperation force,torque,speed,strip thickness）or calculated from figures of the rolling schedule and dimensions of the mill(strip reduction,roll diameter etc).These variables allow to describle the mechanical rolling conditions of all passes in roughing and finishing mills . These variables should be supplemented by the metallurgical rolling conditions .They then give basic information on the conditions which determine wear(specific load ,wear speed)and fire crazing(co-efficient of heat penetration etc).There is a good chance to use the experiences of other mills with various roll grades by analog comparison-as long as the rolling conditions are similar.This method is limited by “abnormal rolling conditions”, which require totally different roll grades,although if it would be much better to eliminate the abnormal conditions.Introduction.in hot strip mills,slabs of 150 to 250 mm thick are rolled to strip1.5 to 12 mm thick.Conventional hot strip mills consist of roughing and finishing stands.The configuration of the roughing mills varies widely .A mill with one reversing stand and one or two continuous roughing stands is called a % conditions mill and a mill with 4 to 6 conditions roughing stands is called a continuous mill .In 3/4 continuous and continuous mills ,the first stands are usually two high stands while the remainder are 4 high stands.In addition to these horizontal stands,several edgers are also used .The finishing mills have a minimum of 4 stands but normally have 6 to 7 stands.Rolling conditions vary from mill to mill,stand to stand and pass to pass.Mill configurations are designed for a desired total stip(thickness)reduction,however,each stand is limited in strip reduction by the maximum separation force, maximum torque ,risk of slippage etc.In order to supply the correct roll for each mill,roll makers ask for details of the rolling conditions and any special circumstances.However,how to use this information?How to compare the conditions of pass No.X and No.X +?There have many discussions over the years but rarely any really good results with these comparisons. For example,looking at roughing mill work rolls,there are so many roll grades being used in different mills that it is evident that the optimum grade to yield the maximum quality for all applications has not yet been found.To date,no theories have been proved. In fact,in many instances the combination of experience and roll perform ance in the mills is totally contrary to the theories of yesterday and today.Even the finest theory does not help if a roll grade fails：“Banding”in roughing stands never created problems,but the handing problem in finishing mills has not been solved by any roll grade. And there is little hope for change in future.There is not single outstanding quality for roughing mills which out-performs all other qualities in every application.This is because rolling conditions vary widely. In this paper an attempt is made to identify some variables which are independent on the mill and the passes in they mill，and then to analyse tile“rolling conditions”.The bases for these analytical studies are actual rolling schedules for similar strip dimensions and qualities from different mills and experience with different roll grades in these mills .We have to identify the different variables for every stand and every pass and then try to find the relationship between these variables and the performance figure for different roll grades. All information about special practices in the mills for producing good strip profile and flat strip,which are of high importance for mill people,are not considered because they probably have no influence on the choice of the correct roll grade.The initial idea was to answer all questions，to solve all problems by having rules for roll wear and fire crazing .We very quickly found that this was impossible .Even with the most sophisticated methods,because we can only study“normal rolling conditions”and every often the so called“abnormal conditions”are every day occurrences .And only the simple figures from the rolling schedules are available and no actual information on loads .torque or the real temperature distribution on strip and rolls，nothing about change of the total rolling program（length,coffin shape.） Therefore we will try to define the rules for normal conditions and the other problem,to eliminate the“abnormal conditions”，is up to the mill people .We have to prove how good our variables for rolling conditions are and how they are affected by tile“abnormal conditions”. Rolling conditions and theoretical background. The rolling conditions ar