TPT March 2009

The technological model is created for computerized development of tool designs for cold tube rolling mills of KhPT and KhPTR types. The model allows calculating of the calibration by three techniques, each of which has its ideal application area depending on plastic properties of the tube metal. The program also includes databases that contain mechanical properties of the steel grades used as well as the information on technical reference documentation for cold worked tubes. This design was successfully tested at KhPT-32, KhPT-55 and KhPT-75 mills at Sinara Tube Works. Figure 8 shows the appearance of the information obtained. Physical simulation of production processes Mathematical simulation is not possible without using physical simulation results; it is only possible to obtain the information about the mechanical properties of metals and the boundary conditions of the working process with the help of physical experiments. To generate the information on the metal resistance to deformation and other physical data, OJSC RosNITI works in close cooperation with Department of Plastic Metal Working of Yuzhno-Uralsk State University, whose research laboratory is equipped with a unique cam plastometer. The main advantage of this plastometer is the possibility to perform fractional deformation that allows the simulation of continuous tube rolling processes and the study of metal softening patterns between passes. Besides, a special container design allows the performance of simulation at a fixed specimen temperature. Figure 9 shows the schematic diagram of the cam plastometer. The possibility of a fractional specimen loading provided by the plastometer allows the development and successful implementation of the experimental research procedure of the resistance of metals and alloys to deformation. It also reveals plastic deformation during experiments excluding errors due to the contact friction during plastic deformation. Furthermore, the process of physical simulation is facilitated with the help of the computerized system for collecting, converting and computer processing of data attached to the plastometer. The equipment for isothermal compressive deformation has allowed the development of the procedure to determine friction coefficient in hot and cold working. The method is based on the known  Figure 8 : The results of computerized design programme for cold tube rolling mill tool design

 Figure 9 : Schematic diagram of the cam plastomter designed by YuUrSU

solution of the variational problem of cylinder yielding. The idea of the method is yielding a cylinder specimen at the plastometer at a predetermined temperature while observing the condition of the specimen contact surface with the working tool. This is undertaken by measuring the specimen contact surface diameter after yielding with the help of a toolmaker’s microscope and computer processing of the obtained data using a simulator. In order to calculate parameters of the cylindrical specimen surface stress-strain state during yielding, the solution of the variational problem of cylinder yielding was further developed. This allowed the considerable increase of the accuracy of determining metal and alloy plasticity via physical simulation using the cam plastometer. Conclusion The effectiveness of the simulation methods used for research and advancement of the tube rolling processes is determined by their multipurpose application. All simulation (mathematical, physical and computerized) methods shall be used to obtain reliable information. The accuracy of setting the boundary-value problem, taking into account its end implementation, has to be ensured to receive reliable results when using mathematical simulation. In the case of computer simulation, in addition to the use of available programs it is advisable to create object-oriented programs. This is because the application of such programs is more convenient for solving practical tasks despite a somewhat limited application area. The development of new computerized analysis procedures for the production processes based on the known analytical solutions can be recommended for an on the spot solution of specific production issues. The implementation of new research procedures for obtaining new kinds of information using the existing laboratory equipment is reliant upon the development of an advanced trend of physical simulation methods. Bibliography: 1. VG Dukmasov, AV Vydrin ‘Simulators and the processes of high-quality flank rolling’ – Cheliabinsk: YuUrSU Publishers, 2002 (p215). 2. VL Kolmogorov ‘The mechanics of metal plastic working’ – Moscow: Metallurgia Publishers, 1986 – p688. 3. VL Kolmogorov, SI Parshakov, SP Burkin, Yu N Loginov et al ‘Plastic metal working technological tasks solution using microcomputer’ – Moscow: Metallurgia Publishers, 1993 – p320.

OJSC RosNITI – Russia Fax : +7 351 734 70 60 Email : maltsevpa@mail.ru Website : www.rosniti.ru

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