A. L. Vorontsov, D. A. Tyalina (The Bauman Moscow State Technical University, Moscow)

The study of combined extrusion of tumblers with the co-bottom part.
Part 4. Mechanical and mathematical analysis of the fourth and fifth variants of the process

Using the general methods of A. L. Vorontsov, a mechanical and mathematical study of the fourth and fifth variants of the process of combined extrusion of tumblers with a conical bottom is carried out. All necessary design schemes are presented. Calculation is obtained that allow one to determine the deformation forces and the values of the plastic deformation regions for each possible variant of the plastic flow of the workpiece metal. These formulas also allow you to determine which version of the deformation will occur in a particular case, and are necessary for the successful design of this operation. The results of confirmatory experiments are presented.
Keywords: die forging; metal tumbler with conical bottom part; combined extrusion.

A. E. Tsibulko, E. A. Romanenko (PJSC «NKZM», Kramatorsk, Ukraine)

Generalized natural strength criterion

A generalized natural strength criterion is proposed based on the dependence of destructive factors: normal and shear stresses on individual components of the specific potential strain energy.
Keywords: strength; normal stress; tangent stress; main stress; relative deformation; potential energy; separation; shear.

S. V. Samusev, V. А. Fadeev (National Research Technological University «MISiS», Moscow)

Investigation of multi-radial schemes for folding a tube billet during continuous shaping in roll calibers of a TESA molding mill

The advantages and disadvantages of single-radius calibration of the tool used in the production of longitudinal welded pipes in the TESA line are examined. Two-radius calibration of MISiS and two-radius calibration with the molding of the peripheral section of the workpiece with constant parameters for all stands of the molding mill are presented. For these calibrations a «flower» of folding are constructed the values of the paths for three fixed fibers of the workpiece and the field of longitudinal deformations for a pipe Ø 50×1,5 mm were determined. The analysis of the process of forming the workpiece by three folding schemes with an assessment of the efficiency of the molding process and the quality of the resulting workpieces are carried out. It has been established that for all three schemes of the forming process, it is possible to obtain high-quality workpieces, but it has been noted that to improve the process it is advisable to use schemes with a falling average fiber in the open caliber section of TESA 30-50.
Keywords: pipe billet; welded pipe; single-radius calibration; two-radius calibration; edge path; longitudinal deformation; molding «flower»; setting parameter.

V. P. Sannikov; A. V. Sannikov (St. Petersburg State Marine Technical University, St. Petersburg)

A new way to fasten pipes in thick tube sheets of heat exchangers with tape-screw conical rolling

The main existing methods of fastening pipes in thick tube sheets of heat exchangers are considered. A comparative analysis of these methods. A fundamentally new method of fastening pipes in thick tube sheets of heat exchangers using direct-acting tape-screw mills is presented. The method has successfully passed industrial testing at several enterprises in Russia.
Keywords: pipe; tube sheet; pipe fastening; rolling.

M. A. Petrov, I. S. A. El-Deeb (Moscow Polytechnic University, Moscow); A. N. Kurov (Group of companies «Parallel», Oryol)

Numerical simulation of cold bulk forming of blank of hexagon head bolt using 3D-models with detalized geometry

The application of 3D-scanning helps to make on objective assessment of the geometric features of an object, used further as an input geometry for numerical FEM-simulation. Obtained by light 3D-scanning technique based on fringed pattern detalized 3D-models of the initial blank and cutting punch were used for such numerical simulation. It was found out, that there are influences of the geometric features of the initial blank on the defect like cavity in the bottom part of the bolt leg on the contact face with the die and of the cutting punch on the flash geometry.
Keywords: 3D-scanning; detalized geometric model; fringe pattern; FEM; QForm; friction factor; bolt upsetting; bulk cold forming; blank of bolt; cutting punch.

A. V. Nesterov, A. K. Musolin, N. V. Gribov (Ryazan State Radio Engineering University, Ryazan); M. N. Musolin (OJSC «Tyazhpressmash», Ryazan)

Automation of forging complexes based on computer forgings profile control technologies

Hydraulic presses are the main tool for producing large-sized forgings in the process of free forging in heavy machinery enterprises. Most of the presses in Russia have been in operation for over 40 years and often cannot ensure that modern production requirements are met for the accuracy of forgings, production strengths and energy savings in the forging process.
Keywords: automation; forging; complex; algorithm; scheme; control; forging.