Increasing in rationality of using of cold extrusion in production of parts such as steel deep glasses

The limited use of cold volume stamping for the production of parts only for narrow traditional range of such parts in mass and large-scale productions is shown. Original technological techniques that improve the quality of products and the punches fatigue resistance are developed to expand the application of this technology to new types of parts. Such techniques used at various stages of the production process by cold forging of deep steel glasses are described. The value of rational design of stamps and the example of design of well-proven production stamp are shown.

Some aspects for increasing of heat-temperature strength of casting complex alloyed nickel-based alloys due to effect of redistribution of alloying elements between γ-solid solution and hardening γ′-phase

The positive effect of alloying elements on the thermal stability of the γ-matrix and the strengthening γ'-phase of casting nickel alloys, and consequently, on the increase in their heat-temperature strength is established. The alloying elements inhibit diffusion processes, thereby increasing the creep resistance of alloys at high temperatures and loads. It is found that the most indicative parameters of the phase composition of the test alloys are the alloying elements distribution coefficients between the γ- and γ'-phases. The basic principles of balanced alloying are formulated, on which the choice of the optimal chemical composition of heat-temperature nickel alloys is carried out.

Interaction of elements in carbon-graphite—Al—Mg—Zn—Cu melt system under combined action of temperature and pressure

Redistribution of chemically active elements is established on its inner surface of pores and at the interface with the alloy when impregnating carbon-graphite framework with Al—Mg—Zn—Cu alloy at temperature of 800 °C under pressure of up to 3 MPa. In this case, change in the solubility of melt elements in aluminum is possible as result of the combined action of temperature and pressure in the impregnation process, created due to the difference in the coefficients of thermal and thermal expansion of the matrix alloy, and the material of the impregnation device during impregnation. Titanium compounds are found in the pores filled with metal that are not added to the matrix alloy, but are formed as result of the contact of the matrix alloy melt with the walls of the impregnation device.

Application of preliminary low-temperature heating for cold forming of complex parts on cold former

The results of experimental studies of flow curves of 32CrB4, 20G2R and 1.4034 (analogue of 40Kh13 steel) steels at different heating temperature of workpieces are presented. Rational intervals of preliminary lowtemperature heating of workpieces made of studied steels are obtained. It allows to decrease forces during cold forging, loads on the working tool and to increase of tool life time up to 2 times.

Development of technique for determining of stamping hammer blow efficiency

The multiple-stage process of large-sized turbine blade blanks on steam-air die-forging hammer is considered. Mathematical modelling of the stamping process of large-sized turbine blade on falling parts 25 t mass stamping hammer is carried out. Measurements of the number of hammer blows and the under-stamping of blade blanks at each stage of the technological process are performed. Method for determining of the hammer blow efficiency is developed. Diagram of the force—displacement of falling parts 25 t mass hammer is constructed. The dependence of the blow efficiency of falling parts 25 t mass hammer is obtained, with can be used in mathematical modelling of the stamping processes of large-sized forgings on this hammer.

Improving in cold resistance of castings made of 20GL type steels

The analysis of the literature data on the steels used for the manufacture of castings operating at negative temperatures and the technology of their manufacture is carried out. The effect of chemical and phase compositions on the strength and impact strength characteristics is revealed. The rational technology for manufacturing of these castings is considered. Methods for obtaining of high impact strength of castings made of 20GL type steels at –40...–60 °C temperatures are given. Modification, microalloying and rational modes of heat treatment are used as methods of rational control of the steels structure. The heat treatment technology of castings, which provides the necessary package of properties and reliable operation, is proposed.

Necessity in development of sheet rolling theory, taking into account nonstationarity of technology and negative dynamic effects

The analysis of the existing modern problems of rolling production related to the need to take into account the nonstationarity of technological parameters and negative dynamic effects for calculating of power parameters and designing of technology and rolling equipment is performed. Theoretical substantiation and research results confirming their relevance are proposed.

Features for friction stir welding of butt joints of casting VAL8 alloy with wrought 1565chN2 and AMg6M alloys

The results of technological features for friction stir welding of butt joints of sheet blanks with thickness of 3 mm made of casting aluminum V AL8 alloy with wrought magnalium group 1565chN2 and AMg6M alloys are presented. It is established that the time resistance of the joints depends on the location of the welded alloys relative to the direction of tool rotation during friction stir welding. The ultimate strength of welded joints of VAL8 alloy with 1565chN2 and AMg6 alloys in automatic argon-arc welding is 0.82...0.84 of the ultimate tensile strength of VAL8 alloy. The grain size in the stir zone practically does not depend on the initial grain size in the alloys to be joined. The destruction of the joints made of VAL8 + 1565chH2 alloys under cyclic loading has multi-focal character and is initiated from irregularities on the surface of the weld. The discrete nature of the change in the chemical composition of the weld metal along the axis of the weld is revealed. The weld is formed by alternating strips of connected alloys with width of 30...90 microns.

Study of stress-strain state of cold-drawn hexagonal steel rods

The results of the stress-strain state during drawing of hexagonal steel rods are presented. The effect of the drawing die angle and the degree of reduction on the distribution of the stress-strain state parameters and the elastic aftereffect of the deformed metal is studied.

Effect of active action friction forces on technological parameters of backward extrusion

The parameters of deformation degree at theoretical and experimental researches of cold backward extrusion processes of hollow glasses-type products are considered. The dependences of their relationship with the relative degree of deformation and the scale of their conformity are suggested. The published results of experimental and theoretical studies on the impact of technological parameters of the backward extrusion process of hollow products in the conditions of active friction forces to reduce the deformation force and stress-strain state of the billet are analyzed. Insuffi ciently studied features of the process and the possibility for expanding of the application fi eld of the backward extrusion method with the active action of friction forces are noted. The method for calculating of the deformation rate required to determine the current stress in the implementation of the hot backward extrusion process.