Semenov

This article presents a scientific and practical commentary to the Russian official professional standards for specialists in installation and testing of thermal equipment; analysis and diagnosis of the technological complexes for thermal treatment; automation and mechanization of the processes of thermal manufacturing. The norms for classifying of the professional engagements and skill levels of these specialists according to the technical difficulty of thermal and thermo chemical equipment and corresponding technological processes were clarified. The concrete examples are represented. The necessity to ensure a high level of professional training of specialists in these areas is shown.Key wards: professional standards; thermal equipment; technological processes; technical difficulty; levels of professional skills.

The article uses numerical experiments to verify a previously hypothesized mechanism of dislocation nucleation particles of chromium- alloyed cementite during a process of carburizing heat-resistant steels, which contain, at least, 3 % chromium. It is shown that alloyed cementite particle nucleation occurs on the chromium and carbon concentration fluctuations in dislocations, thus eliminating the formation of cementite lattice. The proposed mechanism of nucleation explains the origin of the lattice formation when introducing a significant amount of nickel into steel and increasing the process temperature. The guidelines to choose the optimal parameters of carburized layers for hot-resistant steels, which contain nickel of 3% have been developed.

The paper presents great technological capabilities of vacuum heat and thermo-chemical treatment provided by the universal equipment, which enables us to strengthen different heavily loaded machine parts and engineering instruments. A load-bearing capacity of the treated part is defined by the diffusion layer saturation, the structure of surficial region and heart. Technological factors of treatment processes with complicated mechanisms to influence on the resulting features make it reasonable to design the strengthening operating conditions using the calculation methods.

This paper presents a mathematical model of a co-saturating complex alloy steel with carbon and nitrogen in the low pressure atmosphere. They developed software that gave an opportunity to estimate concentration curves of carbon, nitrogen, and basic alloying elements for VKS-10 steel, as well as the main characteristics of the phase composition in tabular and graphical forms on the basis of the parameters of vacuum nitrocarburizing. The effect of the complex chemical composition of the steel on formation of the diffusion layer was taken into account. Sufficient adequacy of the model within the temperature range from 880 to 940 ° C was demonstrated; these temperatures are the same as during high-temperature nitrocarburizing. With the help of this mathematical model patterns of formation of diffusion layers depending on technological factors of vacuum nitrocarburizing were investigated.

The regression dependence of the carbon and nitrogen potential on the acetylene temperature and concentration at saturation of iron and complex-alloy steels in glow discharge plasma was determined. The defining influence of the adsorption rate of acetylene molecules on the intensity of carbon mass transfer was revealed. The most probable reaction of acetylene dissociation was determined according to the analysis of experimental data, thermodynamic calculations and the structure of the acetylene molecule. The influence of the solid solution and the reaction mechanisms of saturation on the mass transfer kinetics of carbon during ion carburizing were described.

An experimental study of carbon and nitrogen saturation of complex-alloyed steel in low-pressure atmosphere was conducted. After the process of vacuum nitrocarburizing the quantity of austenite was increased. Also the dimensions of carbonitride particles were decreased. The control factors of vacuum nitrocarburizing technology were optimized with use of a mathematical model.