The article presents the results of scientific research and industrial experiments aimed at the development of technology to reduce the production cycle of high-strength hull steel. The technology includes an improved reduced heat treatment of ingots made using rare-earth metals and uphill teeming of large sheet ingots. The proposed technology for the preliminary heat treatment of ingots eliminates the high-temperature phase re- crystallization operation, which is unnecessary, according to the authors, since it does not allow partial crushing (grinding) of the metal dendritic structure and homogenization. When using the proposed technology of reduced pre- treatment, phase and structural stresses are sharply reduced. Experiments have shown that the modification of steel with rare-earth metals has a positive effect on the crystallization of ingots, changing the macro- and microstructure of alloy steel. The developed manufacturing technology of high-strength hull steel provides a high level of sheet quality and a reduction in the production cycle time by 10-12 %.
Existing problems of electron beam welding of aluminum alloy constructions are considered. For research purposes, the aluminum-magnesium alloy of grade 1561 up to 60 mm thick was used. The thermal field in the heat influence zone is studied experimentally and analytically on the basis of the finite element method (the «Ansys» program). The effect of electron beam movement (scanning) influence on the quality of welded connections and the surface of the welded parts was studied. On the basis of metallographic studies and mechanical tests of welded metal, it is proved that high quality of welded joints is ensured when the beam moves along a curve of the «compressed brackets» shape. A special generator is designed to control the electron beam, which allows to implement a new type of scanning (compressed brackets). The fundamentals of welding technology for alloy 1561 up to 60 mm thick are outlined. Specific recommendations are given, and two new methods are proposed that will allow the successful use of the developed technology in factories in the production of new products and in the repair processes. Examples and analysis of thermal cycles obtained by calculation and experimental method are given. The patterns of heat distribution along the trajectory of the beam movement for different types of scanning are established. The main types of defects in the formation of the welded joints and those formed in the metal during crystallization are considered. Their interrelation with the parameters of the welding mode is shown.
The article presents numerous experimental data of different researchers depending on the hardness of annealed steels hypoeutectoid on the percentage of carbon content. In addition to the classical Brinell hardness measurement, data of Jagar hardness, Shore, the width of lines on sclerometry Martens, weight loss during grinding on sandpaper are given. Selecting tendentiously experimental data we demonstrate the plateaus on the curves of hardness of annealed hypoeutectoid steels vs. % of C at ~0.5 % С. Similar plateaus were discovered by N.S.Kournakov in the curves of properties around FeAl3, Pb3Na, Cu3Zn, which enables one to follow the analogy and declare a ~ Fe42C phase in the Fe-C system. The anomalies of properties observed in the presence of interim phase at ~ 0.5% С are definitely established (such as magnetic susceptibility, electric resistance, density, ductility, etc.) for melts and austenite. Their derivative is a ferrite-cementite mixture, which – due to the experimentally established metallurgic heritage – may inherit the anomalies of properties of its parent phase. For the three states described (melt, austenite, mixed phase) the anomalies of properties at ~ 0.5 % С should be denoted in some compact way, ascribing them, for example the formula of interim phase of ~ Fe42C. The assumed ~ Fe42С phase has a specific analog in the In-Zn system consisting of eutectic mixture of pure In and Zn, which form an InZn8 phase with their crystal phase, found, similar to ~Fe42С phase under the liquidus bend.
On the basis of six signs of the trip-effect, thermal effect as a result of four independent piec-es of researches, magnetic effect (diffusion change, as in the point of Curie), changes in hydrogen and carbon solubility and two dozens of anomalies based on temperature dependences of physical properties, conversion in iron at ~ 650ºC has been proven. The transformation enables to explain extreme products properties obtained as a result of isothermal transformation of austenite, step tempering, martensite vacation, anomalously high diffusion, appearance of stimulus to austenite recrystallization and other.
The article gives an analysis of the current standard two-dimensional codes, showing their features and applications. It was concluded that the feasibility of developing a new type of two-dimensional codes, the Nanobar code (NBC), in which information can be open (available) and, if necessary, closed (unavailable) to the user through the use of cryptographic encryption techniques. At the same time the new codes provide a significant increase in the volume of coded information that allows us to recommend using them as a local database, in particular for the issue of electronic technological certificates and product passports, personal dog tags for the military, athletes and others. It is noted as an important characteristic that the Nanobar code is able to encode different types of digital information. Due to its characteristics, the NBC is proposed to use as an identification number and protect legal products against counterfeiting. Two variants of the NBC technology application are proposed – with laser printing and printer. For reading information from the NBC, special software was developed, including mobile applications that allow using a smartphone to read the NBC. The basic scope of the NBC application was suggested.
The article analyzes the existing methods for applying the matrix two-dimensional codes. The article describes the developed hardware and software system for the application of the information fields that include: logo, barcode, nanobar code. A comparative analysis of the dimensional characteristics of the existing two-dimensional codes and nanobar code is also discussed. The examples of application nanobar codes on various materials are reviewed.
Simulation modeling of processes in the heat-affected zone by welding low-alloyed steels is of particular importance. This technique is used to study the structure of the metal in heat-affected zone by hidden arc welding of pipes. The causes of a low impact strength in the area of large grain of heat-affected zone welding steel K70 are determined.
