鋼坯火焰清理機的設計—排屑裝置設計

鋼坯火焰清理機的設計—排屑裝置設計,鋼坯火焰清理機的設計—排屑裝置設計,鋼坯,火焰,清理,清算,設計,裝置 7 南昌航空大學科技學院學士學位論文 外文翻譯原文 SHOT BLASTING MACHINES FOR THE BLASTING OF SHEET MILL ROLLS V. I. Meleshko, A. P. Kachailov, V. G. Boikov, V. L. Mazur, T. P, Kobka and I. I. Krivolapov At the present time~ much attention is being devoted to increasing the quality of rolled products, partieularly sheet. To a significant degree this depends upon the preparation of the roll surface. Many plants are engaged in improving the quality of working the roll surface in preparing them for rolling.This article was written by personnel from Zaporozhstal Plant, Magnetogorsk Metallurgical Combine, the Institute for Ferrous Metallurgy, Dnepropetrovsk, and Magnetogorsk Mining and Metallurgical Institute on this very real problem.. The surface microrelief, or roughness, of cold rolled constructional sheet has an influence on the mechanical and production properties of metal, and also on the finish quality of parts made from this sheet. The final surface microrelief of thin sheet steel is formed in a skin pass on work roils which have been given a rough finish with metal shot. Normally the rough surface finish on the work rolls of skin pass stands is produced in pneumatic and rotor shot blasting machines. Experience in their use has shownthat the pneumatic machines used in the country's steel plants do not fill the need for high quality blasting of roll surfaces. In 1969 the Institute for Ferrous Metallurgy, Dnepropetrovsk, did work on the SM-2 shot blasting machine in No. 1 Cold Roiling Mill of Zaprozhstal Plant, which revealed a number of shortcomings in its construction. To provide sheet with the surface roughness required by the specifications of Volga Automobile Plant (R a =0.8-1.6 g),the basic requirements for the design of shot blasting machines were determined, The machine must provide: 1. a constant shot size during operation, in other words, effective removal of shot of the specified size from worn shot; 2. the possibility of controlling air pressure in the collector of the shot blast machine during stable operations; 3. the handling of work rolls of different diameters (400-500 mm) without special equipment on the machine;; 4. simplicity in control and convenience in maintenance. Fig.1 The SM-2 machine (Fig. 1) consists of a stationary closed chamber ! with a trolley on wheels aad movab!enozzles 2~ which under the action of compressed air discharge shot on to the roll surface, a worm conveyor 8, an elevator with a separator 4, the shot blast equipment 5, and an exhaust system 6. The equipment is mounted on a special foundation 1905 mm below the floor level The length of the machine withthe trolley out is 15fl00 ram, the height 4070 ram, and the width 4600 mr~ The dimensions of the rolls handled are 400-500 mm in diameter and 2000-4000 mm in length. The total weight of the equipment is 15 tons. As research has shown, the dynamics of the wear of a working mixture of abrasive and the original condition of the shot changes during operation. During blasting, the shot takes on a wider size range and is worn down, forming many fine particles. The conditions under which the parts are blasted depend upon the size of the shot used. The contamination of the specified size by fine particles disrupts the process, producing a poor quality surface on the rolls and consequently on the sheet. To eliminate these problems it is necessary to either regularly measure the composition of the shot and make appropriate changes in the blasting sequence, which is difficult to do in practice, or to screen the shot during operation of the machine to provide the specified particle size. Stability in the blasting process is also determined by the quantity of shot delivered to the nozzles. It was experimentally established that supplying 0.3-0.4 kg/sec of shot to the two nozzles in operating with an air pressure of 2.5-4.0 atm provided stable operation. Equipping the machine with screening devices is an effective method for maintaining a constant shot size mix. This is confirmed both by data in the literature and by experience in the operation of SM-1 and TsKb_P-1 shot blast machines at Zaporozhstal Plant. The shot is delivered to the surface of the roll by the shot blast equipment, the chamber of which is divided by two diaphragms with charging vents into three compartments and is equipped with an electropneumatic control device. The working mixture from the upper compartment of the chamber drops to the lower and then to the collector. During operation of the machine,the vents are closed (turned on). The shot is poured in either after turning off the valves by the electropneumatic control device, or after shutting down the machine by the operator. When it is turned off, the vent descends, and between it and the diaphragm a circular gap 5 mm wide is formed. The vent is a cone with a slope of about 30% The shot drops slowly through this gap but not completely, and therefore it increases to t0 ram. The loading vents are alternately turned on by the control device. The first time the SM-2 machine was repaired, it was discovered that the control device frequently did not operate because of corrosion of the parts. With normal charging of abrasive (375 kg according to the nameplate), blasting must be stopped after each alternate pass of the nozzles, since after another pass the shot in the lower compartment is insufficient, and during blasting, With nonoperation of the control device, it does not drop from the upper compartment to the lower. Delivery of the nextportion of shot must be done only after the operator disconnects the shot blast equipment from the air system. In this case both charging vents are opened, and the abrasive is fed to the lower compartment. Continuous operation of the machine for three or four passes of the nozzles with nonoperation of the control device and the delivery of shot described above became possible after increasing the standard charge to 650 kg. However, the basic solution of this problem is stable operation of the control device. The used shot is collected by the collecting bunker of the working chamber and drops into the receiving chute of the worm conveyor. The plates parallel to the worm conveyor are at a greater angle, and those perpendicular are at less of an angle, which tends to collect shot on them. Therefore, after blasting one roll it is necessary to shut the machine down to push the accumulated shot on to the screw conveyor. To eliminate this shortcoming, it is possible to lengthen the screw conveyor, which is half the length of the working chamber. In addition, the smaller plate is removed completely,and the parallel plates are elongated to correspond with the length of the worm conveyor. The compressed air supplied to the collector of the shot blast equipment is dried by an oil moisture separator. However, this method of drying is inadequate. Water vapor condenses in the main line and in the shot blast equipment, and as a result shot sticks together in the lower compartment and forms a solid mass. The solid mass clogs the vertical channels along which the abrasive is transported to the collector and disrupts the optimum ratio of shot to air in the blast. This has a detrimental effect on the blasting process and the quality of the roll surface. The presence of moisture in the air causes corrosion of the equipment and causes operation of the pneumatic equipment of the machine to be poorer. Therefore, in designing shot blast equipment,it is necessary to specify equipment for drying the air. Foreign firms, for example, use special drying equipment utilizing water absorbing substances such as silica gel and activated alumina for drying compressed air. The mechanism for moving the nozzle has a number of shortcomings. Application of the jet of abrasive material on to the roll is through a nozzle mounted in an elbow shaped gun (Fig. 2). A shortcoming of the gun is the throttling of the mixture of compressed air and shot where the vertical and horizontal channels join. The junction is a right angle, which causes quick wearing away of the elbow. The cross sections of the channels and nozzle was increased. However, with an increase in the nozzle diameter from 10 to 12 mm (the allowable maximum) the consumption of air increased from 13 to 19 mS/h, which changed the ratio of shot to air in the blast. However, thisratio must be kept constant. Since during blasting it is difficult to make corrections, it was necessary ~o improve the design and increase the wear resistance of the parts. Fig.2 For this purpose a new design of blast guns, in which the diameter of the channels was increased (Fig. 2 b) and the shape of the transition from the channel to the channel and nozzle was changed, was proposed and tested, The new nozzle design is much more effective. After five months of operation,noticeable signs of wear in the elbowand nozzle have not been found, while the old design elbows wore out in a month. The blast guns are moved along the roll by a conveyor belt. Under the action of the weight of the troJ.ley and oscillations caused by its movement along the guides on which shot falling from the surface of the rolls accumulates, the belt gets out of alignment. As a result, the impact of the stream of shot on the surface is not at a right angle, but glancing, which produces a poorer surface quality. Placing a strip under the gun eliminated this problem, and the roll surface quality became satisfactory. In the first period of operation the compressed air tn the SM-2 machine was obtained from the shop main i',ine, which has a pressure of 6 atm. According to readings on a manometer placed before the collector of the shot btaat unit, the air pressure in it did not exceed 4.0 aim. With this pressure, even with the use of the finest shot (DChK-0.8), the roughness of the rolls is at the upper limit (R a = 2.7 #). Therefore, it was necessary to reduce the working pressure of the air. An air valve was used to control the pressure, but it was very sensitive to changes in air pressure, and operation of the shot blast machine was unstaSle. As a result, a reducing valve was placed between the oil moisture separator and the shot blast equipment. This made it possible to control the air pressure in the collector from 4.0 to 2.0 atm with an accuracy of 0.1 atrr. The use of this valve provides stable operation of the shot blast equipment. To blast rolls of different diameters it is necessary each time to change the position of the blast gun, which is not provided for in the design of the SM-2 machine. For example, at the present time to blast a 400 mm diameter roll after a 500 mm roll the machine must be shut down for adjustment. In designing new shot blast machines the possibility of changing the height of the gun must be specified. To observe the blasting process, special observation windows were cut in the long wal! of the lighted working chamber. Nonetheless, observation of the surface of the roll being blasted was difficult. Therefore, three additional 500 W lights, protected by louvers, were placed on the ceiling of the working chamber. Fig .3 Control of the machine (Fig. 3) is from the control panel 2, the valve 5 at the air line, the rheostats for con. trolling the speed of rotation of the roll and the movement of the nozzles, and the push bu~on for starting up the exhaust fan motor, which is behind the machine. Such an arrangement of the SM-2 shot blast machine equipment is not convenient for control The rheostats for controlling the speeds do not have graduated scales, which makes choice of the correct speed difficuR. Actual: 15 for each new position of the control handle it is necessary to determine the speed. These disadvantages must be eliminated in the design of new machines, It is also necessary to improve removal of accumulated metal dust from the horizontal portion of the exhaust line, which is in a difficult to reach location about 4 m above the floor tevel. To provide more convenient placement of the individual units of the shot blast machine and simplify i~maintenance, the Institute of Ferrous Metallurgy has developed and turned over to Zaporozhstal Plant recommendations which have been partially put into use on the existing machine and will be studied in designing similar new machines. The improvement in the SM-2 pneumatic shot blasting machine has made it easily possible to controt and maintain the specified sequence for blasting work rolls for cold rolling and skin pass sheet stands. As a result, Zaporozhstal Plant is mass producing cold roiled constructional sheet with a surface roughness meeting Ferrous Metallurgy Technical Specifications 1-683-69 and 1-686-69. 7 湘潭大學機械工程學院畢業(yè)設計工作中期檢查表 系 機電系 專業(yè) 機械設計制造及其自動化 班級 07興湘機一班 姓 名 葉海龍 學 號 2007964214 指導教師 胡自化 指導教師職稱 教授 題目名稱 鋼坯火焰清理機的設計—總體方案設計和總體裝配 題目來源 ■科研 企業(yè) 其它 課題名稱 鋼坯火焰清理機的設計—總體方案設計和總體裝配 題目性質(zhì) 工程設計 ■ 理論研究 科學實驗 軟件開發(fā) 綜合應用 其它 資料情況 1、選題是否有變化 有 ■否 2、設計任務書 ■有 否 3、文獻綜述是否完成 ■完成 未完成 4、外文翻譯 ■完成 未完成 由 學 生 填 寫 目前研究設計到何階段、進度狀況： 通過對資料的查詢，已經(jīng)確定了鋼坯火焰清理機初步設計方案。現(xiàn)階段著力對各個構件外形設計和計算。與此同時還通過對一些復雜的裝配圖形的裝配和仿真熟悉和了解三維制圖軟件 由 老 師 填 寫 工作進度預測（按照任務書中時間計劃） 提前完成 按計劃完成 拖后完成 無法完成 工作態(tài)度（學生對畢業(yè)論文的認真程度、紀律及出勤情況）： 認真 較認真 一般 不認真 質(zhì)量評價（學生前期已完成的工作的質(zhì)量情況） 優(yōu) 良 中 差 指導教師（簽名）： 年 月 日 建議檢查結果： 通過 限期整改 緩答辯 系意見： 簽名： 年 月 日 注：1、該表由指導教師和學生填寫。 2、此表作為附件裝入畢業(yè)設計（論文）資料袋存檔。 湘潭大學興湘學院 畢業(yè)設計任務書 設計題目： 鋼坯火焰清理機的設計—排屑裝置 學號： 2007964214 姓名： 葉海龍 專業(yè)： 機械設計制造及其自動化 指導教師： 胡自化 系主任： 一、主要內(nèi)容及基本要求 1、鋼坯火焰清理機排屑系統(tǒng)項目的重要性 2、鋼坯火焰清理機排屑系統(tǒng)項目的設計基本任務 3、鋼坯火焰機排屑系統(tǒng)總體功能分析 4、鋼坯火焰清理機排屑系統(tǒng)設計方案可行性論證 5、總結和撰寫設計說明書一份（附光盤）； 6、CAD制圖，本文一張A0裝配圖紙及其零件圖，課題組一套完整圖紙 7、翻譯相關外文資料一份； 二、重點研究的問題 1、熟悉和掌握鋼坯火焰清理機相關性能方面的知識； 2、熟悉和理解鋼坯火焰清理機的結構參數(shù)； 三、進度安排 序號 各階段完成的內(nèi)容 完成時間 1 熟悉課題及基礎資料 第一周 2 調(diào)研及收集資料 第二周 3 方案設計與討論 第三～四周 4 初步方案可行性論述 第五～八周 5 CAD軟件的學習 第九周 6 CAD制圖 第十周 7 撰寫說明書 第十一周 8 英文文獻翻譯，答辯 第十二周 四、應收集的資料及主要參考文獻 [1]秦大同.機械傳動科學與技術.北京：清華大學出版社，2003. [2]齒輪手冊編委會．齒輪手冊(上冊)．北京：機械工業(yè)出版社，1990 [3]付則紹．新型蝸桿傳動．北京：石油工業(yè)出版社，1992 [4]姚立綱,李尚信.超環(huán)面行星減速器的設計與制造研究[J].機械傳動, 2001, 25(4): 17-20. [5]姚立綱.超環(huán)面行星蝸桿傳動的嚙合分析和加工研究[D].哈爾濱:哈爾濱工業(yè)大學, 1996 [6]許立忠,曲繼方,趙永生.超環(huán)面行星蝸桿傳動效率研究[J].機械工程學報, 1998, 34(5):20 [7]張躍明.超環(huán)面行星蝸桿傳動的嚙合理論研究.學位論文.哈爾濱工業(yè)大學機械工程系,1993.7 [8]張春麗,徐曉俊,董申.超環(huán)面?zhèn)鲃拥墓に嚫倪M方案及其齒面研究[J].中國機械工程, 2000, 11(7): 749-752.