Design (√)
Paper ()
I. Literature review
1. Brief introduction of hydraulic AGC
Since the early 1950s, automatic thickness control (AGC) has been widely used in plate mills, especially strip mills, and has developed to a very mature stage. The function of AGC system is to eliminate the thickness deviation of rolled piece.
The traditional electric AGC has been replaced by hydraulic AGC because of its poor adjustment accuracy, low efficiency and slow response speed. Hydraulic AGC system includes thickness measurement, thickness comparison and adjustment, and roll gap adjustment. Generally, it consists of position feedback loop and pressure feedback loop. The feedback signals of the two feedback loops are compared by the comprehensive proportional regulator, and then input into the electro-hydraulic servo valve to adjust the flow of the valve and control the stroke of the hydraulic cylinder, so as to realize the automatic control of the thickness of the rolled piece.
2. Research significance of the subject
At present, the test and diagnosis technology of hydraulic AGC servo cylinder for large rolling mills in China is not mature. The servo cylinder of large rolling mill has short stroke, large rolling force and high frequency response, and there is no suitable method, standard and related technology in China, so it is often impossible to judge the fault position, which will cause a lot of waste of spare parts and manpower. Therefore, it is of great significance to develop high-precision detection equipment suitable for AGC servo cylinder detection of large rolling mills.
3. Development status of AGC in modern rolling mills
There are 27 heavy plate mills in China, including 7 with a roll length of more than 3000 mm and the rest with a roll length of 3000 mm. The widest mill in China is Angang 4300mm heavy plate mill, which is modified from foreign second-hand equipment. China has 1 4200mm thick plate mill, which is now installed in WISCO. Jigang and Qinhuangdao rolling mills have installed two sets of 3500mm thick plate mills respectively. In addition, Shougang and Shanghai Steel installed 3300mm rolling mills, and WISCO, Hangang, Angang, Liugang and Jiugang installed 2800mm medium plate rolling mills respectively [1].
There is a tendency to build compact tandem mills abroad. For example, Matsushima Company in Japan installed a three-stand, six-high cold-rolled strip mill. The initial thickness of strip steel is 0.4 ~ 3.5 mm, the final thickness is 0. 15 ~ 1.0 mm, the width is 600 ~ 1300 mm, the rolling speed can reach 35 m/s, and the coiling weight can reach 50 t ... Each stand of this mill includes work rolls, intermediate rolls and backup rolls. The roller diameters are 385mm, 5 10/0mm and1.300mm respectively, and the roller body length is1.420mm.. ..
4. The role of the mill frame
The rolling mill is the main equipment of the steel plate production line, and the frame is an important part of the rolling mill, which bears all the rolling force of the rolling mill. In the rolling process, the rolling force of rolling metal acting on the roller is all transferred to the frame through the roller bearing, bearing seat, screw and nut, which is completely absorbed by the frame and not transferred to the foundation. Therefore, the frame must have sufficient strength and rigidity [2].
Second, the main content of the design (paper)
Preliminary determination of the overall structure: master the basic composition, structure and rolling principle of AGC hydraulic system;
The main contents of the design:
1. Overall structural design of hydraulic cylinder test bench
2. Frame structure design
3. Calculation of frame strength and elastic deformation
Third, the design (research) scheme
1. Investigate, collect information and read relevant materials;
2. Understand the basic composition, structure and rolling principle of AGC system;
3. Preliminary determination of the overall structure;
4. The main contents of the design:
(1) Overall Structure Design of Hydraulic Cylinder Test Bench
⑵ Frame structure design
⑶ Calculation of frame strength and elastic deformation
5. Graduation thesis writing, 1.2 million words or more;
6. Translate English materials with more than 1000 words;
7. Graduation defense.
IV. Organization of work
stage
Main work to be completed
Planned start-stop time
1
Consult and collect relevant information and write the opening report.
08.3. 17-08.3.30
2
Overall structural design of the test bench
08.3.3 1-08.4. 13
three
Frame structure design
08.4. 14-08.5.04
four
Calculation of strength and elastic deformation of frame
08.5.05-08.5.25
five
Classification and translation of English documents
08.5.26-08.6.0 1
six
Review and reply
08.6.02-08.6. 15
Verb (abbreviation of verb) main references
[1] Wang Fengxi. Development of large rolling mills. Heavy machinery technology. 2000( 1):50
[2] Bo Han. 1500 Mill Frame Finite Element Simulation Optimization. Heavy industry and lifting technology. 2006 (3): 14。
[3] Cheng. Mechanical design manual-hydraulic control. Chemical Industry Press, 2004
[4] Cheng. Mechanical design manual-hydraulic transmission. Chemical Industry Press, 2004
Sun Zhang' ang Finite element analysis and optimal design of closed stand of rolling mill. Metallurgical equipment. 2004 (3): 8 ~ 1 1.
Wang Hongbin. Structural analysis of large tonnage hydraulic cylinder test-bed. Construction machinery. 1997 ( 10): 26 ~ 27.
Cao Yuping is from Xiang Yan. Hydraulic transmission and control. Tianjin University Press, 2003
Sixth, the guidance of teachers' opinions.
Signature:
date month year
Seven, the Department of graduation design (thesis) work leading group opinion.
Signature:
date month year