A. 英语高手请帮忙很急，这周就要交了
Whether can the rolling mill bearing operating performance use effectively, the quite great degree is decided by the lubrication situation, the lubricant is been called “the bearing's fifth big spare part”. The rolling mill bearing's damage reason above 40% is the insufficient lubrication creates, must therefore rece the rolling mill bearing consumption, must select is suitable in the exploitation conditions lubrication method and the quality lubricant, but must design the installment to prevent foreign matter invasion and so on water and oxide skin reliable packing assemblies. the present rolling mill bearing mainly uses the fat lubrication and the oil gas lubrication. Presently mostly the factory uses the easy to do fat lubrication way lubrication, if has the possibility to adopt the oil gas lubrication technology, may cause the rolling mill bearing to be under the quite ideal lubrication condition to work, will rece the bearing consumption large scale.
1 The fat lubricates the fat lubrication the method to have easy and feasible, the roller replacement convenient characteristic, the application is very widespread. Should according to the rolling mill bearing operating temperature, the rotational speed, the roll force as well as the seal waterproofing performance, the impact vibration size, supplies situation choice being suitable and so on fat method lubricants. Must select, the viscosity to be strong thermostablly, the ep performance good as well as the anti-water drenches the performance high regular factory the lubricant. Should choose according to the rolling mill bearing's operating feature contains EP chemical additive 2#, 3#, the lithium base fat or the polyuria fat. although the high performance lubricant procurement cost is high, but the amount used has been short, the bearing life is long, the total comprehensive cost reced. Moreover the lubricant packing quantity wants certainly right amount and fills the arriving, the different trademark's lubricant cannot mix uses, to cause the rolling mill bearing active face to be at the lubricant film normal state throughout.
2nd, the sufficient fat measures when the primary packing lubricant the bearing inner space stuff then, must fill up and down the enough quantity lubricant regarding the vertical roll or in the web roll each bearing seat lid. After each time roll changing, must inspect the lubricant whether to harden the nigrescence, whether by impurity pollution, whether to oxidize the emulsification. If has the above situation to replace the lubricant thoroughly and to inspect the seal and the seal structure prompt replacement or the improvement; If after situation Shang Haoke supplemented the new fat, continued to use.
3, the oil gas lubricate the oil gas lubrication are the bearing ideal lubrication way, the bearing compress the spatial gas range middle the work to lubricate the oil dripping once in a while to enter in the bearing, the lubricating oil keeps in the bearing, the air carries off bearing movement in quantity of heat, simultaneously prevents the exterior impurity water vapor to plunge in the bearing. The oil has not been atomized the pollution of the environment.
4th, packing assembly the bearing's seal is must maintain the internal good lubrication condition, and prevents the cooling water, to oxidize the iron sheet, the impurity to plunge the active face to lengthen bearing's service life. As a result of the rolling mill bearing enclosure question, the bearing failure most is approaches the body of roll side the spot, the bearing is frequently because of the lubricant pollution, the outflow, causes the components active face to wear, flaking even to disrupt, specially cold belt rolling mill's emulsion permeating, causes the lubricant to expire is quicker
Bearing's seal divides into the bringing seal and the outside seal two kinds. The outside seal mainly uses the design which the labyrinth type and the contact type unify. The labyrinth level are more (is not lower than two-pole) the gap smaller seal effect to be better. Labyrinth gap basis bearing size size way chosen to one-sided 0.6~1.5mm; Axial 4~6mm.
Contact skeleton oil seal: It applies on the rolling mill is quite widespread, to increase the effect to be possible 2-3 compound uses. The oil seal has the directivity, cannot install instead. The hot-rolling mill general attire two oil seals, two oil seal lip mouth must to the bearing seat outside, prevent the outside contamination to plunge. The cold belt rolling mill general attire three oil seals approach a bearing's oil seal lip mouth to inward, with prevents the lubricant overflow influence to roll over the material quality quantity. Uses when the oil seal must be careful, avoids installs when the roller colliding and damaging the lip mouth, affects the seal effect.
RBR packing ring: This is one kind of rolling mill bearing special-purpose rubber lip type packing ring, widely is applied in recent years. The RBR packing ring uses the axial seal the way, his/her the lip mouth pastes in gland's basic plane, the influence which beats the roller, the bearing interior's old fat may not overflow, the exterior cooling water, oxidizes the iron sheet, the impurity to enter by the lip mouth impediment, has the good seal effect. When easy to operate, roll changing the roller loads the bearing seat not any influence.
B. 轧辊是干什么用的
轧辊是轧钢厂轧钢机上的重要零件，利用一对或一组轧辊滚动时产生的压力来轧碾钢材。它主要承受轧制时的动静载荷，磨损和温度变化的影响。
轧机上使金属产生连续塑性变形的主要工作部件和工具。轧辊主要由辊身、辊颈和轴头3部分组成。辊身是实际参与轧制金属的轧辊中间部分。它具有光滑的圆柱形或带轧槽的表面。辊颈安装在轴承中，并通过轴承座和压下装置把轧制力传给机架。传动端轴头通过连接轴与齿轮座相连，将电动机的转动力矩传递给轧辊。轧辊在轧机机架中可呈二辊、三辊、四辊或多辊形式排列。
轧辊的分类方法有多种，主要有：（1）按产品类型分有带钢轧辊、型钢轧辊、线材轧辊等；（2）按轧辊在轧机系列中的位置分有开坯辊、粗轧辊、精轧辊等；（3）按轧辊功能分有破鳞辊、穿孔辊、平整辊等；（4）按轧辊材质分有钢轧辊、铸铁轧辊、硬质合金轧辊、陶瓷轧辊等；（5）按制造方法分有铸造轧辊、锻造轧辊、堆焊轧辊、镶套轧辊等；（6）按所轧钢材状态分有热轧辊、冷轧辊。各种分类可以相应组合而使轧辊有更明确的含义，如热轧带钢用离心铸造高铬铸铁工作辊。