The influence of technological modes of sintering: the displacement velocity of laser beam V, laser power P, scanning step S and preheating temperature of powder material t on the quality of sintered surface layer of aluminum powder PA-4, copper powder PMS-1 and cobalt- chromium-molybdenum powder DSK-F75 were studied.

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Influence of layer-by-layer laser sintering conditions on the quality of sintered surface layer of products

Controlling the processes, which take place during consumable-electrode shield-gas welding, is one of the main problems of the welding industry. The paper shows that under the certain conditions the electrode-metal drop and heat distribution in the weld area are influenced by the active shielding gas jet. The paper provides the results of modeling heat distribution in the weld area and active shielding gas outflow from the traditional and double-jet welding torch nozzles.

Simulation of Active Shielding Gas Impact on Heat Distribution in the Weld Zone

The processes taking place in a drop of a molten electrode metal and in a metal of a weld pool play the dominant role in formation of joint welds properties. In consumable electrode welding with jet gas shielding under certain conditions a drop of an electrode metal is influenced by the main forces as well as by the force of a shielding gas jet impact which depends upon the method and composition of a gas shielding in a welding area. The results of research have stated that the force of a shielding gas jet impact on a drop of an electrode metal in double-jet gas shielding is twelvefold as in one-jet one; it is directed along the electrode to a workpiece and stimulates stability of the electrode metal drops transfer into a weld pool.

Gas-Dynamic Impact of a Shielding Gas Jet on the Drop Transfer when Welding with a Consumable Electrode

A combination of various factors and phenomena determines the quality of the welded joints. The basic role in setting the properties of the welded joints belongs to the processes taking place in the drop of the melted electrode metal. The paper considers the influence and vector components of the basic forces on the melted metal drop in gas jet shielded welding a moment before the drop transfers from the electrode to the weld pool. Methods of calculating the force exerted by a shielding gas jet on the drop of the electrode metal and subject to its dissociation are offered. The frequency and stability of drop transfer to the weld pool increase with the growth of the shielding gas impact force on the electrode metal drop in double jet gas shielding.

Calculation of Gas-Dynamic Impact of the Active Shielding Gas on the Electrode Metal Drop in Gas Jet Shielded Welding

The paper develops scientific and technological bases for fabrication of titanium carbide which is a nanocomponent of composite materials. The authors determine optimum technology specifications and the main titanium carbide properties: fineness of titaniferous raw materials, carbide-forming agent quantity, set temperature of plasma flow, tempering temperature, titanium carbide yield, productivity, specific surface, size and shape of particles. The paper includes equations to describe how the major specifications of the fabrication technique influence the content of titanium carbide and free carbon in the end product.

https://iopscience.iop.org/article/10.1088/1757-899X/91/1/012017/pdf

Titanium Carbide: Nanotechnology, Properties, Application

The given article studies the changes in thermal cycle and cooling rates of steel 30ХГСА weld joints at various distances from the weld center using modern thermal imaging equipment. The analysis of the experimentally obtained and calculated thermal cycles showed that the calculated cycles almost match the experimental ones in terms of quality but the time distribution of calculated values is 4-5 times smaller than that of the experimental ones. On the base of experimental results and theoretical investigation of the thermal cycles for fusion-welding in СО2 we have developed an improved formula for calculating heat conduction for machine single-pass welding. The difference between the calculated and experimental values of thermal fields does not exceed 10%.

Study of Thermal Cycle and Cooling Rate of Steel 30XГCA Single-Pass Weld Joints

The results of investigations carried out to study the effect of the dynamic characteristics of power sources on the stability of melting and electrode metal transfer to the weld pool in consumable...

Investigation of the stability of melting and electrode metal transfer in consumable electrode arc welding using power sources with different dynamic characteristics

D A Chinakhov

Papers

Simulation of Active Shielding Gas Impact on Heat Distribution in the Weld Zone

Gas-Dynamic Impact of a Shielding Gas Jet on the Drop Transfer when Welding with a Consumable Electrode

Study of Thermal Cycle and Cooling Rate of Steel 30XГCA Single-Pass Weld Joints

Calculation of Gas-Dynamic Impact of the Active Shielding Gas on the Electrode Metal Drop in Gas Jet Shielded Welding

Investigation of the stability of melting and electrode metal transfer in consumable electrode arc welding using power sources with different dynamic characteristics