CN-116894304-B - Four-way valve control AGC cylinder design method for plane shape control of heavy and medium plate mill

CN116894304BCN 116894304 BCN116894304 BCN 116894304BCN-116894304-B

Abstract

The invention provides a four-way valve control AGC cylinder design method for plane shape control of a heavy and medium plate mill, and relates to the technical field of hydraulic control and mechanical design. The method comprises the steps of firstly, primarily calculating the piston diameter of an AGC cylinder according to the maximum rolling force of a rolling mill and the maximum design working pressure of the AGC cylinder, determining the piston diameter D of the AGC cylinder after the primarily calculated piston diameter of the AGC cylinder is rounded upwards, primarily calculating the diameter size of a piston rod of the AGC cylinder according to the relation between the steady-state rollback speed of the AGC cylinder and the diameter of the piston rod and the diameter D of the piston rod of the AGC cylinder, primarily calculating the lower limit size of the diameter of the piston rod according to the strength requirement on the piston rod in the rolling process, and finally determining the final diameter D of the piston rod according to the larger value of the primarily calculated diameter size of the piston rod and the lower limit size of the piston rod. The AGC cylinder designed based on the invention is beneficial to meeting the process requirement of hot rolling plane shape control and improving the production efficiency of a production line.

Inventors

WANG GUIQIAO
ZHANG ZHIYONG
DING JINGGUO
GAO YANG
NIU WENYONG
HUA FUAN
LI JIANPING

Assignees

东北大学

Dates

Publication Date: 20260505
Application Date: 20230612

Claims (5)

1. A four-way valve control AGC cylinder design method for controlling the plane shape of a heavy and medium plate mill is characterized by comprising the following steps: step 1, primarily calculating the diameter of a piston of an AGC cylinder according to the maximum rolling force of a rolling mill and the maximum design working pressure of the AGC cylinder; Step 2, rounding up the piston diameter D 1 of the AGC cylinder which is calculated preliminarily, and determining the piston diameter of the AGC cylinder according to the rounded up piston diameter; step 3, primarily calculating the diameter size of the piston rod of the AGC cylinder according to the relation between the steady state rollback speed of the AGC cylinder and the diameter of the piston rod and the diameter of the piston of the AGC cylinder; the relationship between the steady state rollback speed of the AGC cylinder and the diameter of the piston rod is shown in the following formula: (1); Wherein C d is the flow coefficient, Is the area gradient of the spool of the servo valve, x v is the spool displacement of the servo valve, P s is the servo valve inlet pressure, Is the density of hydraulic oil, F is the load force applied to a single AGC cylinder in the rolling process, F 1 is the minimum load force which can be applied to a single AGC cylinder in the rolling process, F 2 is the maximum load force which can be applied to the single AGC cylinder in the rolling process; Order the 0< K <1, and the formula (1) is simplified to obtain: (2); Order the After the piston diameter D is determined, the steady state retraction speed of the AGC cylinder is determined under the condition of fixed opening degree of the servo valve Proportional to the square of M; in the formulas (1) and (2), all variables are of the International units system, if P s units are taken as MPa, F units are taken as kN, and D units are taken as mm ; When f=f 1 , the k value at which M takes the maximum value is calculated as k 1 , and when f=f 2 , the k value at which M takes the maximum value is calculated as k 2 ; The diameter size of the piston rod of the AGC cylinder is calculated preliminarily, and the diameter size is shown in the following formula: ; Wherein d 1 is the diameter size of a piston rod of the AGC cylinder which is calculated preliminarily, and the unit is mm; Is a reduction speed compensation coefficient; step 4, calculating the lower limit size of the diameter of the piston rod according to the strength requirement of the piston rod in the rolling process; and 5, determining the final diameter of the piston rod according to the larger value of the diameter size of the piston rod and the lower limit size of the piston rod which are calculated preliminarily.
2. The design method of the four-way valve controlled AGC cylinder for controlling the plane shape of the heavy and medium plate mill according to claim 1, wherein the piston diameter of the AGC cylinder calculated preliminarily in the step 1 is shown in the following formula: ; Wherein, the The piston diameter of the AGC cylinder is calculated preliminarily, wherein the unit is mm, the unit is F max is the maximum rolling force of the rolling mill, the unit is kN, and the unit is P max is the maximum design working pressure of the AGC cylinder, and the unit is MPa.
3. The method for designing the four-way valve controlled AGC cylinder for controlling the plane shape of the heavy and medium plate mill according to claim 2, wherein the step 2 is characterized in that the piston diameter of the AGC cylinder is determined by: when D 1 after upward rounding is less than or equal to 500mm, the value of the piston diameter D of the AGC cylinder is referred to ISO3320 standard, and when D 1 after upward rounding is more than 500mm, the value of the piston diameter D of the AGC cylinder is selected according to the sealing size series for the piston provided by cylinder sealing manufacturers.
4. The design method of the four-way valve controlled AGC cylinder for controlling the plane shape of the heavy and medium plate mill according to claim 3, wherein the lower limit size of the diameter of the piston rod in the step4 is shown in the following formula: ; Wherein d min is the lower limit size of the diameter of the piston rod, and the unit is mm; the unit is MPa for the allowable stress of the piston rod; N is a safety coefficient; The yield strength of the piston rod material is expressed in MPa.
5. The design method of the four-way valve controlled AGC cylinder for controlling the plane shape of the heavy and medium plate mill according to claim 4, wherein the specific method of the step 5 is as follows: the larger value of d 1 and d min is assigned to an intermediate variable d mid , namely when d mid is less than or equal to 450mm, the value of the diameter d of the piston rod is referred to the ISO3320 standard, and when d mid is more than 450mm, the value of the diameter d of the piston rod is selected according to a sealing size series for the piston rod provided by a cylinder sealing manufacturer.

Description

Four-way valve control AGC cylinder design method for plane shape control of heavy and medium plate mill Technical Field The invention relates to the technical field of hydraulic control and mechanical design, in particular to a four-way valve control AGC cylinder design method for controlling the plane shape of a heavy and medium plate mill. Background For the hydraulic AGC control process of conventional constant thickness rolling, only the load reduction speed of an AGC cylinder is generally focused, and a three-way valve control mode shown in FIG. 1 is generally adopted. Under the control mode, the diameter D (mm) of the piston of the AGC cylinder is calculated preliminarily according to the maximum rolling force of the rolling mill and the maximum working pressure of the AGC cylinder, then the calculated result is rounded, the diameter D (mm) of the piston rod is taken in two modes, namely (1) D-K (K is 100mm less than or equal to 150 mm), the larger D is generally, the larger K is generally, and (2) D is determined according to the speed ratio of the cylinder. However, the three-way valve controls the rollback process of the AGC cylinder by means of the constant back pressure of the rod cavity, and has obvious difference with the flow characteristic of hydraulic oil entering the rodless cavity during the extending process of the AGC cylinder. Therefore, the practical significance of the speed ratio of the three-way valve control AGC cylinder is not obvious. The application material with the application number 2023103077451 has already elucidated that the rollback speed of the AGC cylinder is slower in a three-way valve control mode, and the four-way valve control mode is used for realizing the functions of quick depression and quick rollback of the AGC cylinder at the same time, and the four-way valve control AGC cylinder is shown in figure 2. Research shows that under the four-way valve control mode, if the diameter D of the piston of the AGC cylinder is the same as other working conditions (such as oil source pressure, rolling force and the like), the diameter D of the piston rod has obvious influence on the rollback speed and even the dynamic performance of the AGC cylinder. The diameter d of the piston rod obtained based on the conventional design mode is generally larger, and an optimization space exists. Therefore, optimizing the size design of the AGC cylinder has important significance for improving the dynamic response speed of the four-way valve control AGC cylinder. Disclosure of Invention The invention aims to solve the technical problem of providing a four-way valve controlled AGC cylinder design method for controlling the plane shape of a heavy and medium plate mill, aiming at the defects of the prior art, and realizing the design of the size of the mill AGC cylinder in a four-way valve control mode. In order to solve the technical problems, the technical scheme adopted by the invention is that the four-way valve control AGC cylinder design method for controlling the plane shape of the heavy and medium plate mill comprises the following steps: Step 1, primarily calculating the diameter of a piston of the AGC cylinder according to the maximum rolling force of the rolling mill and the maximum design working pressure of the AGC cylinder, wherein the diameter is shown in the following formula: Wherein, D 1 is the piston diameter of the AGC cylinder calculated preliminarily, the unit is mm, F max is the maximum rolling force of the rolling mill, the unit is kN, and P max is the maximum design working pressure of the AGC cylinder, and the unit is MPa; Step 2, rounding up the piston diameter D 1 of the AGC cylinder which is calculated preliminarily, and determining the piston diameter D of the AGC cylinder according to the rounded up D 1; When D 1 after upward rounding is less than or equal to 500mm, the value of the piston diameter D of the AGC cylinder is referred to ISO3320 standard, and when D 1 after upward rounding is more than 500mm, the value of the piston diameter D of the AGC cylinder is selected according to the sealing size series for the piston provided by a cylinder sealing manufacturer; Step 3, primarily calculating the diameter size of the piston rod of the AGC cylinder according to the relation between the steady-state rollback speed of the AGC cylinder and the diameter of the piston rod and the diameter D of the piston of the AGC cylinder; the relationship between the steady state retraction speed of the AGC cylinder and the diameter of the piston rod is shown in the following formula: Wherein C d is a flow coefficient, ω is an area gradient of a valve core of the servo valve, x v is a valve core displacement of the servo valve, P s is an inlet pressure of the servo valve, ρ is a density of hydraulic oil, F is a load force applied to a single AGC cylinder in a rolling process, F E [ F 1,F2];F1 ] is a minimum load force applied to the single AGC cylinder in the rolling process,