MELTING RATE CALCULATION ON PREHEATED WIRES OF VARIOUS CHEMISTRY UNDER ARC WELDING

The empirical factors dependences on the process parameters for the welding wires of various chemist ry are o btained for t he empirical formula permitting to calculate the wire melting rate (feed) in a wide range of current s, preheat temperatures, electrode diameters , and stick - outs under the welding in carbon dioxide on the reversed p olarity current. The calculation accuracy by the empirical formula and by the known computational melting model of the same wires is comparatively appraised. The effect of stick - out and preheat temperature increase of the welding wires on the productivity - boosting features of their melting is asse ssed

INITIAL ARC IGNITION CONTROL IN GAS-SHIELDED WELDING

The control method of the initial arc ignition in the gas-shielded welding is offered. It is based on the short-circuit current limitation after heating the wire stick-out with the metal passing current to the plastic state for the time of the wire burnout approach point at the stick-out-to-work distance not exceeding the arc breaking length. The dependences describing the conditions necessary and sufficient for the reliable establishment of the welding process after the first wire-work contact are experimentally investigated and analytically determined

Research in domain of droplet impingement erosion of the power equipment: lookback study and context analysis

The main work objective is the creation of the scientific background for correct determination of a set of requirements to the fabrication material with a high-wearing feature under the droplet impingement erosion. A review of a backward and present state of the art of the national and foreign investigations in the field of the droplet impingement erosion of metal materials is carried out. The main outcome is as follows: insufficient fundamentality of research in this area; limitation of the used theoretical models; one-sided approach of many authors to the phenomenon that combines a whole set of factors of different physical nature. On this background, the author's concept of the erosive wear process of metal under the influence of two-phase mist flow is presented. Particular attention is paid to a new scientific hypothesis of the active hydrogen effect on the fracture of metal under the hypervelocity dropwise collisions

MODELING OF THIN SAWS NOISE EMISSION

Noise level dependences of thin saws of the metal-cutting machines and woodworkers are resulted. It is shown that abatement of noise in the source can be achieved by the rational choice of the vibration cushioning specifications for the vibration protection systems