Key Engineering Materials Vol. 910

Abstract: This paper describes QForm computer simulation of a large-sized blade preform shaping, using cross-wedge rolling. Scenarios of friction consideration between the workpiece and the tool are examined.

Abstract: Numerical simulation of the temperature field and parameters of the turning process of workpieces made of 45 and 12Kh18N10T steels is performed. The front angle of the cutter, as well as the coefficients of chip friction on the front surface of the tool μ₁, the flank surface on the workpiece μ₂, and the coefficient of friction on the yield stress μ were selected as variable parameters. The degree of influence of the variable parameters on the tangential component of the cutting force, the friction force on the front and flank surfaces of the cutting tool, the power of heat sources, contact temperatures and the average temperature of the workpiece is estimated.

Abstract: This article presents the results of experimental studies of the effect of processing conditions on the corrosion resistance of polished parts made of stainless chromium-nickel steel of austenite class 12X18N10T. It is established that the introduction of the ultrasonic field energy into the shaping zone during grinding can increase the corrosion resistance of parts by 12-15 %, depending on the elements of the grinding mode. The latter is explained by a significantly lower heat-force stress during processing, which, in turn, leads to a decrease in the magnitude and depth of distribution of technological residual tensile stresses along the surface layer.

Abstract: This paper is devoted to hot isostatic pressing (HIP). HIP capsule simulation software has been analysed. Abaqus has been proved the most appropriate simulation tool, which enables finite element analysis and allows users to define their own material properties via a special control program. Specific features of HIP simulation models have been evaluated. Powder densification model has been analysed and implemented. A control program has been developed to factor in elastic and plastic material behaviour. Preliminary simulations have been run for a one-element model and a capsule model.

Abstract: The article outlines the method of digital simulation of electrochemical processing, which allows calculating the shape of the electrode-tool in conjunction with the mode, taking into account the real conditions of processing. The technique allows you to ensure the maximum possible performance with specified processing accuracy and limitations that exclude critical phenomena in the channel between electrodes during intensification of modes. Mathematically, the task is presented in the form of minimax problem with application of penalty functions.

Abstract: Two new parameters – reduced wear and reduced integral microhardness of the modified surface layer was used to evaluate the effectiveness of surface hardening technologies. The existence of a correlation between the entered parameters is shown, the regression equation is obtained based on the analysis of experimental data of the wear of a tool made of steel CrWMn and U10 treated with a laser with coatings in the reflow mode. We construct the functional dependence of tool wear on this parameter.

Abstract: This article is devoted to expanding the technological capabilities of the gas-forming stamping method by increasing the pressure of combustion products acting on the surface of a workpiece stamped. Therefore, a scheme of a two-chamber device and a method for compressing the fuel mixture is proposed. The essence of the method is that of carrying out the stamping products under the high gas pressure, which is created by compression and subsequent combustion of the gaseous fuel mixture. To ensure the compression of the fuel mixture, the device is equipped with two combustion chambers separated by a piston. Due to this method, the pressure rises sharply. Under the influence of the combustion products' pressure, the workpiece is intensely deformed and fills the cavity of the matrix. This method of sheet stamping, implemented on a two-chamber device, will increase the gas pressure on the surface of the forged workpiece to 70-80 MPa at a fuel mixture pressure of 1 MPa, which ensures stamping of a variety range of parts in almost all branches of small-scale production related to metalworking.

Abstract: On the example of shape memory alloys in coarse-grained and ultrafine-grained states there is demonstrated an influence of pulse current on deformation behavior, microstructure and mechanical properties during cold rolling. The combination of cold rolling with the introduction of a pulsed current stimulates an increase in the deformation ability and strong structural refinement into the region of nanograins in a hard-deformed shape memory TiNi alloy. For both coarse-grained and ultrafine-grained structural states, the maximum achievable one-time and the total degree of deformation are higher in the case of using a pulsed current. Subsequent annealing improves the strength and functional properties. It has been shown that effect of pulsed current on deformability during cold rolling is higher in an alloy with a high content of impurities.

Abstract: The design of the screw for osteosynthesis of the spine was developed. The requirements that apply to medical devices of this type were taken into account. The 3D model of the screw was developed in the Siemens NX CAD system. Route technological process of processing and technology for manufacturing a polyaxial pedicle screw using high-performance equipment was developed. Progressive cutting tools providing high processing productivity, specified dimensional accuracy and quality of the processed surface, were selected. The geometry of the tool cutting part was optimized, the material of the tool was selected. Geometric parameters and quality control were carried out using modern measuring equipment. The developed technology for the manufacture of a screw for osteosynthesis made it possible to minimize the labor intensity of production.

Abstract: The paper is devoted to the formation of established microgeometry and physical and mechanical performance of the surface layer (SL) of aluminium alloy parts (D16 and D16T GOST 4784-2019, DIN equivalent is 3.1355 or AlCuMg1 for ISO), by ultrasonic surface machining (USM). It is found that for the materials under study it is more proficient to use the USM scheme with applying vibrations of a tool along a tangent to the surface to be treated. The influence of static load and machining speed on height roughness parameters and microhardness of the surface layer is revealed. USM with the tangential scheme of vibration applying forms a specific regular microgeometry on the surface of the parts. This microgeometry differs from other ones obtained by methods of surface machining based on plastic deformation, including diamond burnishing.