KSHP. OMD №6-2020

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

The study of combined extrusion of tumblers with the co-bottom part.
Part 7. Kinematic and stress state of the plastic region located under the conical surface of the punch

To extrude cups with a conical bottom part, the kinematic and stress state of the extruded metal in the region of the plastic deformation zone located under the conical surface of the punch was determined using the A. L. Vorontsov method of plastic flow. The obtained formulas will be used to determine the stress state in the region of the source located under the central flat part of the working end face of the punch. In the future, the results of this mechanical-mathematical analysis will also allow us to investigate the question of the presence of a punch taper that is optimal in strength.
Keywords: tumbler with a flange; die forging; direct extrusion; stresses; deformation.

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

A new version of the energy criterion of strength in bulk compression

A new version of the energy criterion of strength under bulk compression is proposed based on the maximum component of the specific potential strain energy.
Keywords: strength; main stress; equivalent stress; specific potential strain energy; ball tensor.

A. S. Povarov; M. G. Allenov («Tyazhpromarmatura» JSC, Moscow)

Mastering the technology of hot stamping of half-shells of valves from sheet blanks

The process of hot stamping of half-shells is considered according to the drawing scheme with flanging from a sheet blank. A study was made of the influence of the geometry of the flanging punch and friction on the tool on the curvature of the ends of the forging. Defects arising in the stamping process, methods for their prediction and elimination are identified. The simulation of the stamping process in the Qform software package and the experimental results are compared.
Keywords: hot stamping; flanging; half-shells; sheet blank.

Yu. A. Tsekhanov (Voronezh State Technical University, Voronezh), Ya. B. Nemirovsky, F. I. Zlatopolsky (Central Ukrainian National Technical University, Kropyvnytskyi, Ukraine)

Management of the process of forming blanks with deformation pulling

The results of studies on the management of the process of forming blanks with deformation pulling are presented. The possibility of changing axial deformations from shortening to elongation is established. It is proved that their change is due to the appearance of a local plastic zone in the contact zone. Technological factors have been identified to control axial deformations. Resource-saving technological processes for the restoration of worn parts have been developed.
Keywords: deforming drawing; control; axial deformations; contact pressure; shortening; elongation.

I. A. Izakov (Salyut Machine-Building Production Association, Moscow); D. V. Kapitanenko, S. V. Vydumkina (VIAM, Moscow)

Improving the design of a heating system for isothermal deformation

The article presents the design of a specialized installation for isothermal extrusion, which allows for quick replacement of replaceable parts of dies, punch and die with an ejector, work has been done to study the installation, as a result of which changes were made to its design.
Also, the article presents the feasibility of using flat (sheet) metal resistance heating elements to increase the reliability and service life of heaters,  presents the design of the installation with such heaters.
Keywords: isothermal heating facility; heating elements; muffle; inductor; thermal.

A. V. Kornilova (Peoples' Friendship University of Russia, CJSC «Prochnost’», Moscow); Zho Zayar (MSTU «Stankin», Moscow); Tet Paing (Military Computer-Technological Institute, Republic of the Union of Myanmar)

On the issue of pre-sale preparation of forging equipment in the secondary market

The article discusses the problems of pre-sale preparation of forging equipment in the secondary market. It is shown that with pre-sale preparation it is necessary to build maps of permissible defects. For cracks, the “no straining” criterion should be applied. The most effective way to avoid the growth of defects is to limit the technological  force of the press.
Keywords: defectiveness; semi-elliptic crack; modeling; stress intensity factor; nominal force.

O. S. Zhelezkov, V. A. Arzamastseva, A. A. Laktyushin (Magnitogorsk state technical University, Magnitogorsk)

Parameters of the zone of local loss of contact between the workpiece and the tool during plastic bending of rod products

On the basis of full-scale and computer modeling, the effect of the emergence of a zone of local loss of contact between the workpiece and the tool during plastic bending of rod products is revealed. Regularities of change of parameters of non-contact zone depending on the sizes of a preparation and the bending tool, and also modes of plastic bending are established.
Keywords: plastic bending; rod products; two-support bending; finite element modeling; punch; punch stroke; bending angle; non-contact zone parameters.