Mathematical Models for Forecasting of 10Mn2VNb Steel Heavy Plates Mechanical Properties

The problem urgency for determining the optimal rolling and heat treatment schedules for providing the required indices of heavy plates physical and mechanical properties is shown. The use of statistical mathematical models for solving this problem is substantiated and the methodology for their design is described. Statistical mathematical models were designed using the mathematical statistics methods and Data Mining tools to determine the yield strength, ultimate tensile strength and percent elongation for 10Mn2VNb steel plates rolled under 3600 heavy plate mill conditions. Software for the numerical implementation of these statistical mathematical models has been developed. Applied software has been developed for the numerical implementation of the statistical mathematical models for predicting the heavy plate’s mechanical properties, and high calculation accuracy has been confirmed with the ones help: 95.82% for the yield strength, 96.78% for the ultimate tensile strength, and 91.48% for the percent elongation. The regularities of the influence for finish rolling factual temperature in the finishing stand of 3600 heavy plate mill and the plate thickness on 10Mn2VNb pipe steel physical and mechanical properties were identified by processing the database and using the designed software.

Automated control system for fire cutting units on a plate mill

One of the most important indicators of a plate rolling mill efficiency is a metal consumption (cost coef-ficients) per ton of product. Reduction of metal consumption coefficients is ensured by the accuracy of the set geometric dimensions realization during the rolling, increasing the accuracy of geometric dimen-sions of the plates that are cut from the rolls on fire cutting units, as well as by operating in the minus field of tolerances on the geometric dimensions of the plates. Improving the accuracy of the geometric dimensions of the plates, cut from the rolls on the fire cutting units, is achieved through the automatic control of these units. The article describes the technical solutions, implemented in the automated con-trol system of fire cutting units (the ACS FCU) of the heat treatment department and fire cutting of a plate mill 3600. The purposes of the ACS FCU creation include an increase in accuracy and stabilization of the geometrical sizes of the work pieces cut out of plates through the automatic control; reduction of metal consumption coefficients due to the operation in the minus field of tolerances on the geometric dimensions of the work pieces; replacement of obsolete equipment with the modern one in order to in-crease the reliability of the mill equipment operation; increasing the ACS FCU service life through the use of modern equipment with high reliability characteristics; reduction of unplanned equipment down-time that may arise as a result of the ACS FCU technical means failures. The automated control system of fire cutting units has been set up, tested and put into operation; a metrological certification of the system has been carried out as well. The results of the ACS FCU testing and its subsequent operation have confirmed the system efficiency and the performance of all its intended functions. This system can be also implemented in the processes of treatment of other rolling mills, equipped with the units for the fire cutting of metal.

Development of Digital Control Algorithms for the Mechatronics System Drives of Reversing Plate Mill Stands

Expanding the plate mill product range implies the improvement of control algorithms for the mechatronics control system drives of the reversing stands. The most important objectives include increasing the accuracy of geometric dimensioning and tolerancing, as well as improving the profile and surface flatness of rolled pro­ducts. The structure explaining the automatic ROLL-GAP CONTROL concept is provided, which allows controlling the thickness and gap between SMS-Demag AG rolls. This concept is implemented in the '5000' mill stand of Magnitogorsk Iron and Steel Works. The structural diagram of the automatic gauge control system (AGS) is presented. The functional diagram of the hydraulic gap control (HGC) system is presented, which includes a fast proportional control channel and a relatively slow integral position control channel. The principle of automatic thickness control is discussed, implemented in the automatic gauge control (AGC) system of the mill stand TCS controller. The diagram and dependences are prepared for the calculation of the nonlinear thickness controller parameters. The functions of the RAC regulator are described, intended for compensation of the tensile difference (gap spacing) at the mill stand sides. The dynamic impact compensation system functions are considered. The removal of the roll bending and deformation control signals is substantiated. The disadvantages of AGC are noted for sheets with a thickness below 10 mm. The most dangerous case is the tearing of metal fragments from the rear sheet side caused by the incorrect operation of the gauge control system. A method for hydraulic gap control is proposed based on the fast increase of the roll gap in the rear part of the rolled sheet during the last passage when rolling thin sheets. The results of experimental studies made on the '5000' mill are presented. The efficiency of the proposed control method has been confirmed. The oscillograms of signals are presented characterizing thickness variations. HGC and AGC systems with the proposed adjustments are proven to provide high-accuracy hydraulic position control and thickness control along the sheet length and width.

Automatic control of the rolling mode “at an angle” on a reversing hot rolling mill

One of the most important indicators of the quality of control of the rolling process on a plate mill is the accuracy of obtaining the geometric dimensions of rolled metal, which determines the cost of metal per ton of product, in particular, the accuracy of the implementation of a given width. The sheet width exceeding the width of the initial billet, under rolling on plate mills, is obtained at the stage of breaking the width in a horizontal stand. Breakdown of the width in most cases is carried out by rolling the workpiece at an angle of to the longitudinal axis of the future sheet. However, if the rotation of the roll (slab) is not possible at the stated angle (for example, when the width of the roll is less than the distance between the rollers), then a part of the considered stage is carried out by rolling “at an angle” less than . In the process of such rolling, the dimensions of the roll along all axes and its shape in plan are changed (initially the rectangular shape takes the form of a parallelogram). The paper describes the mathematical description for one of the options for forming the width of a thick sheet when rolling “at an angle” in relation to an automated control system for the technological process of a plate mill. On the basis of the concepts describing the formation of the roll in the plan during rolling “at an angle”, the expressions were obtained that relate the parameters of the roll and the rolling mode. The problem of automatic control of the rolling mode “at an angle” is formulated. The proposed calculation of the rolling mode, which is implemented at a pace with the rolling process, provides a rectangular roll of a predetermined width for a minimum number of passes, subject to restrictions on the reduction in passes. The described approach to the automatic control of the rolling mode during rolling at the “angle” is implemented in the mathematical support of the system for calculating the rolling parameters and heat hardening of the plate mill 5000.