V. N. Chudin (RUT (MIIT), Moscow); A. V. Chernyaev (Tula State University, Tula)

Hot extrusion process modes for curved pipes

The process is examined and relationships for calculating the hot extrusion process for pipeline pipes are proposed. The workpiece material is assumed to be viscoplastic and relaxes over time during deformation. Stress relaxation increases at low deformation rates. Therefore, the process modes depend on the workpiece deformation rate. To calculate the force mode, an upper-bound method is used for the discontinuous velocity field of workpiece element displacements. Relationships for assessing the continuity (damageability) of the workpiece material are derived based on fracture mechanics. 
Keywords: viscoplasticity; power; speed; pressure; continuity.

A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

The third stochastic longevity model

The article is devoted to the issues of the third stochastic model of longevity. This is a model that takes into account the probabilistic nature of the durability process, taking into account the stochastic characteristics of the object's parameters and loads. Using this theory, it is possible to estimate the estimated durability of structures and parts having similar characteristics and operated under the same conditions. The theoretical solution of the problem under consideration is given using cumulant.
Keywords: durability; the third stochastic model of durability; statistical series; law of durability distribution; cumulant.

A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

Heating of the end rod by a continuously operating point heat source

The article is devoted to the theoretical issues of heat transfer through a rod. The paper considers the process of heating the end rod with a point heat source. Therefore, the process under consideration is non-stationary. The solution of the problem is given using Green's functions and is presented as a series. The result obtained can be applied in calculating the heat transfer of cylindrical parts and determining the temperature regime.
Keywords: rod; heating; thermal conductivity; unsteadiness; Green's function; heat source function.

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

Investigation of backward-and-forward extrusion of tumblers with a co-bottom part.
Part 28. Experimental verification of theoretical formulas for extrusion with bending

This paper examines the process of cold extrusion with bending of cups with a conical bottom made of a hardening material. Methods for performing specific calculations of the deforming force for various geometric parameters of free and constrained extrusion are demonstrated in detail. A comparison with experimental data obtained during the extrusion of AD1 aluminum alloy demonstrates the high accuracy of the derived calculation formulas.
Keywords: die forging; metal cup with a conical bottom; combined extrusion; stress; deformation.

A. D. Khvan (Voronezh State University, Voronezh); D. V. Khvan, A. A. Sidorenko (Voronezh State Technical University, Voronezh)

Device for plastic upsetting with torsion of long cylindrical blanks

The article discusses the design of a device for plastic precipitation with torsion of long cylindrical workpieces. It can be used in production when designing die tooling to implement technology to increase the durability of cutting tools such as reamers, countersinks, end mills, etc.
Keywords: device; conical sectors; cylindrical billet; angle of taper vectors

V. V. Ovseets (Togliatti State University, Togliatti)

The effect of a double-reversible drawbead on the sprinback of metal after drawing

This article is aimed at obtaining data on the springback of a sheet blank after the technological operation of drawing with a stamping tool using a two-reversible drawbead. The previously developed two-reversible drawbead was aimed at optimizing the braking scheme of the workpiece in order to obtain the car part «Trunk outer panel» from a smaller workpiece and without loss of quality of the resulting product. It is necessary to determine how the double-reversible drawbead will affect the resulting springback in the metal of the workpiece after the part is drawn by cold sheet stamping. The springback of the sheet material of the workpiece refers to the elastic deformation of the metal after the completion of the stamping process when the die is opened. It indicates the amount of deviation from the original shape of the resulting product. The greater the springback in the area of the product, which in the future will be the part itself, and not the waste, the greater the deviation during installation of the transition to the subsequent technological operation, which may affect the accuracy of the resulting part. The geometry and dimensions of the future part, the use of various forces of the press, the material of the workpiece, the thickness of the workpiece and the technical structural elements of the press as a drawbead can affect the springback created during the stamping process. In the topic of this article, a study will be conducted on the created springback of the product after the technological operation of drawing using a basic drawbead and a design two-reversible drawbead in order to determine whether the springback of the workpiece after the use of a two-reversible drawbead is capable of negatively affecting the resulting product. 
Keywords: stamping; drawbead; CAE; Autoform; workpiece braking scheme, stress in die; springback.

D. V. Chernov, I. A. Monakova (JSC «NPO Bazalt», Moscow); S.A. Evsyukov (Bauman Moscow State Technical University, Moscow)

Study of the corrugation formation process on the workpiece surface by hot plastic deformation

The article examines the process of forming a corrugated surface on a metal workpiece using hot plastic deformation. The aim of the study is to investigate the features of material deformation and the stress–strain state during corrugation formation. Numerical simulation based on the finite element method was used to analyze the process in the QForm software package.
Keywords: metal forming; hot forming; corrugated surface; numerical simulation; finite element method; QForm; stress-strain state; defect formation; workpiece ellipticity.

D. V. Chernov, I. A. Monakova (JSC «NPO Bazalt», Moscow); S.A. Evsyukov (Bauman Moscow State Technical University, Moscow)

Study of the drawing process of corrugated sheet parts using numerical modeling

This study investigates the deep drawing process of corrugated sheet parts using numerical modeling in the QForm software package. The stress-strain state of the workpiece was analyzed using the Kolmogorov criterion to assess strain inhomogeneity and the probability of defect formation. It was established that when drawing is performed in a single operation, bottom rupture occurs due to local strain concentration (D > 1), which is confirmed by experimental data. The mathematical model was validated, demonstrating good qualitative agreement between the simulation results and the experiment. A three-stage drawing scheme is proposed, which ensures uniform material flow and produces a defect-free workpiece. The obtained results can be used in the design of technological processes for drawing corrugated parts.
Keywords: deep drawing; sheet metal forming; corrugated parts; numerical simulation; QForm; stress-strain state; Kolmogorov criterion; strain inhomogeneity; bottom rupture; multi-stage drawing; model verification.

V. A. Zyryanov, D. V. Vasiliev, V. V. Kireev (Industrial University of Tyumen, Tyumen)

Arrangement of cutting inserts in the assembled initial contour of the hob milling rack

Creating assembled structures for mechanical engineering enterprises with replaceable carbide cutting inserts is an effective solution for gear machining. A fundamentally new technical solution is proposed that improves the efficiency of machining tools by arranging the carbide cutting inserts in the assembled initial contour of the hob milling rack. The implementation of a group cutting pattern in a composite hob cutter is achieved by using a larger number of main and side cutting inserts on an Archimedean tool worm. This allows for consistent machining allowance reduction, reduces the feed rate to the cutting insert, ensures uniform milling, and reduces impact loads on the cutting elements of the composite tool.
Keywords: carbide; composite hob cutter; progressive cutting pattern; gear.

V. E. Ovsyannikov, Yu. A. Tempel, M. O. Chernyshov, U. S. Putilova, O. A. Tempel, A. S. Gubenko, E. V. Lisina (Industrial University of Tyumen, Tyumen)

Assessing the impact of machining on the surface roughness of polymer filament 3D printed parts

This paper examines the impact of machining on the surface microgeometry of 3D printed parts. Machining is performed using a standard cutting tool with multifaceted carbide inserts. Roughness is measured and controlled using a profilometer. Changes in the surface roughness profile structure are studied, and the relationship between turning modes and the resulting surface roughness parameters is identified.
Keywords: machining; roughness; modes; parts; additive manufacturing.