To create new technological processes for obtaining complex thin-walled magnesium alloy spills with gas protection of the melt in the melting and distributing units of the injection molding complex, regularities, mechanisms and systems of regression equations of the influence of the main technological factors on the conditions of protection of the magnesium melt surface were established. for the development of technological processes, and the modernization of equipment and automated control systems of injection molding complexes.
For the first time, a technique was developed to investigate the surface tension of magnesium melts directly in industrial metal-melting and dispensing units with gas protection of magnesium melt, and the main factors of influence on surface tension were determined. The regularities of obtaining magnesium alloys using the pulse supply of a gas mixture to protect the magnesium melt, where the factors were chosen as temperature Т1 and alloy surface tension σ, the sulfuric anhydride content SO2 and sulfur hexofluoride SF6, and as a response - the life of the protective film (before ignition), an analytical and regression analysis of the results obtained, and it was determined that the increase of the limit of destruction of the protective film for magnesium alloys Y is significantly affected by the content SO2 (0,2-0,8%), that is, when the SO2 content increases, the value of Y inversely decreases from 420 to 140 s, ie it decreases threefold, and the optimal parameters of the named main factors of influence on the pulse processing of the magnesium melt are found, which are for the values of SO2 and SF6 content,%, Ti and σ within 660-700 and 520-550 din/m, 3,0-4,0•10-3 m3/kg and 0,002-0,004 m3/kg, which allows to increase the threshold of the film on the surface of the magnesium melt within 560-620 sec. At the same time, it was found that the costs of the components of the protective mixture, namely SO2 and SF6, at their impulse flow 12 and 19 times lower compared to the technology of continuous supply of these protective gases into the atmosphere of the melting unit.
An automated system for controlling and controlling the technological process of gas protection of magnesium melt in melting and distribution units of injection molding complexes was created using the mechanism and regressive models of the influence of the basic technological parameters, including surface tension and temperature of magnesium melt, the composition of the mixture of protective gases for the lifetime of on the surface of a magnesium melt in a melting or dispensing unit of injection molding.
The operational reliability of the created system of control and control of the technological process of gas protection of magnesium melt in the melting and distribution units of injection molding complexes according to certain characteristic features of reliability is carried out: parameter of the flow of failures; average recovery time; coefficient of technical use; the total utilization rate for the statistical processing of information obtained as a result of two years of operation of the created control system for the casting processes of magnesium alloys with gas melt protection. The processing of the obtained statistical information allowed us to determine the parameters of operational reliability of the working system: for the system as a whole 334 h, for the system to be repaired - 295 h, for the system which is not repaired 379 h, and the failure rate for the system as a whole does not exceed the value 3x10- 4 1/year.
Accelerated tests of the pulse supply system of gas protection, which provide simultaneous tests of the pulse supply of shielding gases with a known operational reliability of the basic protection system under the flux, were carried out. h, and a similar indicator for magnesium melt flux protection systems is 39•10-4 1/h, that is, the failure rate when using the basic method is 30% higher than the meth and protection of liquid magnesium in a gas shielding medium.
The technological processes of melting of magnesium alloys in the protective gas atmosphere with continuous or impulse their feeding into the melting or distributing unit, as well as the automated system of control and control of the technological process of gas protection of the magnesium melt in the melting and distributing units of injection molding complexes with the evaluation industrial exploitation in mass and mass production of magnesium alloy castings.
The equipment and automated control systems of the injection molding complex with continuous and impulse process of gas protection of the melt of magnesium alloys, as well as for the implementation of the technological process of casting of magnesium alloys into vacuum molds were refined to implement the created technologies for the protection of magnesium melt.
