Studying changes of limit deformations and mechanical properties of steels of different structure under single and multiple explosive loading

The ultimate deformation capacity of stainless high-alloyed austenitic nitrogen-containing steel and low-alloyed chromium-nickel-molybdenum steel up to the moment of failure under single and multiple blast loading in the air has been investigated. The paper presents data on the change in the mechanical properties and structure of these steels as a result of explosive loading to the limit and to the specified level of deformation.

RESULTS OF THE APPLICATION OF NEW TECHNOLOGIES IN INCREASING RESOURCES IN HIGH PRESSURE DRILLS

In oilfield practice, as well as in the transportation of oil and gas, great importance is attached to the use of high-pressure valves. Since the demand for this fleet of equipment is growing, it is especially important to increase their resources and reduce their cost on this basis. Along with the constructive and technical measures taken in this direction, serious attention should be paid to improving the choice of materials for the manufacture of parts and their production technology.. The article is devoted to the discussion of the results obtained when using the coquille technology for the manufacture of parts made of low-alloy chromium-molybdenum steel Keywords: high-pressure gate valve, body, gate, seat, hardness, wear.

Analysis of the Advantages of Laser Processing of Aerospace Materials Using Diffractive Optics

We considered possibilities of an application of diffractive free-form optics in laser processing of metallic materials in aerospace production. Based on the solution of the inverse problem of heat conduction, an algorithm was developed that calculates the spatial distribution of the power density of laser irradiation in order to create the required thermal effect in materials. It was found that the use of diffractive optics for the laser beam shaping made it possible to obtain specified properties of processed materials. Laser thermal hardening of parts made of chrome–nickel–molybdenum steel was performed. This allowed us to increase the wear resistance due to the creation in the surface layer of a structure that has an increased hardness. In addition, a method of laser annealing of sheet materials from aluminum–magnesium alloy and low-alloy titanium alloys was developed. Application of this method has opened opportunities for expanding the forming options of these materials and for improving the precision in the manufacturing of aircraft engine parts. It was also shown that welding by a pulsed laser beam with a redistribution of power and energy density makes it possible to increase the strength of the welded joint of a heat-resistant nickel-based superalloy. Increasing the adhesion strength of gas turbine engine parts became possible by laser treatment using diffractive free-form optics.

DYNAMIC STRUCTURAL ANALYSIS OF ENGINE CRANKSHAFT AT DIFFERENT ANGLE OF CRANK TURNS FOR THREE DIFFERENT MATERIALS

For many years, engines have been one of the main power machinery of different kinds of applications, and the main part of power machinery is a crankshaft that converts the piston’s reciprocating displacement with four-link mechanisms into rotary motion. . The major limitation of the engine crankshaft is fatigue failure due to repeated load caused by bending and torsional load. In this paper, the comparative dynamics structural analysis was carried out for three different materials such as forged steel, cast iron, and chromium-molybdenum steel with different angles of turns of cranks from 0° to 720° and to predict the stresses, deformation, and fatigue life of crankshaft without compromising its weight, strength and reliability. The 3D CAD model was simulated with FEA software. The simulated results show that by applying bending load and torsional load for three materials, the maximum stresses produced in the fillet area of the main bearing journal and in the fillet area of the crankpin journal at a crank angle of 360° respectively. The deformation results revealed that maximum deformation occurs at the mid-surface of the crankpin. From fatigue life prediction it was observed that forged steel and chromium-molybdenum steel shows better fatigue life as compared to cast iron. Moreover, in the comparative study, it was concluded that chromium-molybdenum steel shows fewer stresses and better fatigue life. Therefore it is suggested that chromium-molybdenum steel would be the better option for manufacturing crankshaft.

Development of a Technology of Isothermal Annealing With the Use of the Forging Heat for Chromium-Molybdenum Steel

The article discusses the results of investigations performed during a thermo-mechanical treatment of forgings made of chromium-molybdenum 42CrMo4 grade steel. The treatment was realized during a regular series production. The forging process was combined with a heat treatment carried out directly after forging on a specially adapted station. Such a production technology will make it possible to eliminate the step of repeated heating of the forgings. On the example of an element of a steering gear, it was demonstrated how it is possible to perform an isothermal annealing process starting from the temperature at which the trimming of the forgings ends. During the cooling of the forgings, it is enough to maintain the temperature at the proper level in order for the exothermal phase transformation of austenite into pearlite to take place. With an appropriate design of the processing line, the heat released during the transformation could be used to maintain the applied temperature, thus limiting the consumption of energy needed to power the devices. The test results show that, with the properly selected temperature of isothermal annealing, it is possible to obtain an equilibrial ferritic-pearlitic structure in the required hardness scope. Introducing such a solution into the industrial practice would allow significant savings of the energy used for the heat treatment.

Microstructure and selected properties of Ni-Cr-Re coatings deposited by means of plasma thermal spraying

The article presents the results of research on plasma sprayed Ni-Cr-Re coatings. The substrate was 16Mo3 chromium-molybdenum steel used in the production of boilers. The coatings were sprayed with Oerlikon Amdry 4535 80% Ni, 20% Cr powder with 20-45µm granulation. 1% metallic rhenium was added to the base powder using a high energy ball milling method. Rhenium is a heavy, high-density metal. As an alloying addition, it improves the heat resistance of alloys, creep resistance and high temperature oxidation. Rhenium alloys are widely used in the energy and aviation industries as an alloying additive to prevent creep. Observations were made on an optical microscope and a SEM microscope. Hardness tests and optical surface testing with a profilometer were carried out.