International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In this paper the deformation force of the forging process in step-wedge strikers was studied. At the first stage, the study of the deformation force using computer modeling in the Deform-3D software package was carried out. At the second stage, an experimental study of the deformation force during the broaching of workpieces in step-wedge strikers using thermometry was carried out. It is established that the experimental results have a high convergence with the simulation values. The increasing level of difference in results is associated with heat losses during intermediate operations, which are usually ignored during modeling.

Presented article deals with the description of the technology of pattern steel production – forging welding, evaluation of fracture surfaces and mechanical tests of examined samples (resulting steel and its individual components). The damascus steel (pattern steel) was prepared by forge welding from a packet consist of a few hundred layers. Marbling was created by folding layers of 2 components: hard and tough steel of different thickness. For evaluation of mechanical properties was applied: Charpy impact test. The evaluation of the fracture surfaces of individual samples was performed by scanning electron microscopy (SEM). The values of mechanical properties of pattern steel themselves are in the range of values of mechanical properties of individual components. The fracture surfaces of the materials have a characteristic relief (in relation to the mechanical properties of the individual components).

The study of the microstructure evolution during forging in a new design strikers implementing alternating deformation based on computer modeling by the finite element method was carried out. The influence of the flat face inclination angle was studied, for which models with an inclination angle of 0, 15, 30 and 45 degrees were studied. It was established that the most optimal option is the use of strikers with an angle of 30°. On this strikers configuration the influence of the workpiece heating temperatures and the punch movement speeds was studied. The analysis of these technological parameters on the microstructure evolution showed that both parameters affect the structure grinding intensity, while the influence of the heating temperature is more significant.

A computer simulation of the broaching of the workpiece in step-wedge-shaped strikers of the first and second configurations was carried out by the finite element method. The comparison was made according to the following parameters of the stress-strain state: equivalent strain, average hydrostatic pressure, damage criterion, as well as the deformation force. A comparative analysis of the stress – strain state showed that the second configuration of step-wedge-shaped strikers is the most optimal option for implementing the process of broaching rectangular or square blanks. When using them, a more uniform distribution of the stress state is realized, the deformation processing is sufficiently realized in comparison with the broaching in step-wedge-shaped strikers of the first configuration

A series of piston hypereutectic silumin based on Al – (15÷20) % Si, alloyed with copper, magnesium, nickel, chromium is investigated. The mechanical characteristics of ingots from experimental alloys were determined: temporary tensile strength, hardness, relative elongation depending on the composition of the alloys, and temperature coefficient of linear expansion (TCLE). It is shown that the tensile strength of forged blanks is 1.5-2.4 times higher than ingots of hypereutectic silumins. The resulting structure of forgings ensures their high plasticity (relative elongation δ = 5.7÷7.5%; relative narrowing Ψ = 10.3÷14.2%). The optimal mode of heat treatment of deformed silumin is determined: quenching from step heating and aging, which allows increasing the strength of forgings up to 370-470 MPa. Moreover, the plasticity indicators remain at a high level, and the average thermal expansion coefficient of the alloys is (18.0 ÷ 19.2) · 10-6 K-1 in the range of 50 ÷ 200 ° C.

For simulation of processes of compaction or forging of products from powder materials, a method of permeable elements is proposed. The essence of the method is to use elements whose shape is regulated in advance, and, unlike the finite element method, where the elements coincide with the material volumes and their masses are unchanged, here the masses elements are variable, and material can flow between adjacent cells. Examples of using the method for modeling the processes of forging of porous preforms in closed and open dies, as well as in a closed die with a compensation cavity, are presented.