Salt flux. Salt solvent at a temperature of 400 °C, in the molten state covering on the surface of the magnesium die casting melt, cut off the magnesium liquid in contact with the air, preventing magnesium oxidation reaction, salts, based on the carnallite and coupled by MgCl2 and KCl composed of low melting point eutectic mixture, adding high melting point fluorite powder (CaF2) about 20%. In addition as the outer cover and the melt purification. Cover the protective effect of salt can be maintained at 800 °C. The disadvantage of the salt flux is in contact with moist air to produce corrosive chloride and hydrochloric acid gas formation, have great effects on machinery and equipment, and working environment. In addition, the salt flux is easily formed in the inclusion in the casting, casting quality damage.
Inert gas. At present in the industrial application of a large number of nitrogen and argon can be used to protect the magnesium die casting melt, the purpose of which is to cut off the oxygen source, nitrogen can prevent combustion, and Mg slow reaction, generate powderlike Mg3N2 membrane, the door temperature below 650 °C and Ar gas will not be and mg occurred reaction, but there are still mg evaporation.
Inhibitory element. The elements of the inhibition are Be, Ca, Zn. Beryllium have a high diffusion velocity in magnesium die casting melt,The generated BeO has high thermodynamic stability and small volatile tendency. BeO at the surface of the melt formation pressure stress, in the melt coverage have enough BeO, density coefficient is 1.68, played the role of a good protection.
Reactive gas. SO2 and SF6 can be used as reactive gas for the protection of molten magnesium alloy die casting materials, temperature up to 740 °C. Consumption of SO2 in the atmosphere accounted for only 1% of the total volume, in the foundry workshop as protective gas cost minimum, but has the following disadvantages: in and exposed to the air generated by the reaction of sulfuric acid and the formation of gaseous SO3 and the machine and peripheral equipment to promote corrosion. The use of quality steel for all equipment accessories and pipes. -- SO2 and SO3 are toxic and irritating odor, harmful to human health. SO2 and SO3, at very low concentrations, also have good protective effect and SF6 non-toxic, SF6 and molten magnesium contact together constitute a MgF2 dense protective layer.
The above article from KENOS official website (http://www.kenos-diecasting.com/) kenosblog1508
The original address: http://www.kenos-diecasting.com/news_show_98.html, reproduced please specify.
Inert gas. At present in the industrial application of a large number of nitrogen and argon can be used to protect the magnesium die casting melt, the purpose of which is to cut off the oxygen source, nitrogen can prevent combustion, and Mg slow reaction, generate powderlike Mg3N2 membrane, the door temperature below 650 °C and Ar gas will not be and mg occurred reaction, but there are still mg evaporation.
Inhibitory element. The elements of the inhibition are Be, Ca, Zn. Beryllium have a high diffusion velocity in magnesium die casting melt,The generated BeO has high thermodynamic stability and small volatile tendency. BeO at the surface of the melt formation pressure stress, in the melt coverage have enough BeO, density coefficient is 1.68, played the role of a good protection.
Reactive gas. SO2 and SF6 can be used as reactive gas for the protection of molten magnesium alloy die casting materials, temperature up to 740 °C. Consumption of SO2 in the atmosphere accounted for only 1% of the total volume, in the foundry workshop as protective gas cost minimum, but has the following disadvantages: in and exposed to the air generated by the reaction of sulfuric acid and the formation of gaseous SO3 and the machine and peripheral equipment to promote corrosion. The use of quality steel for all equipment accessories and pipes. -- SO2 and SO3 are toxic and irritating odor, harmful to human health. SO2 and SO3, at very low concentrations, also have good protective effect and SF6 non-toxic, SF6 and molten magnesium contact together constitute a MgF2 dense protective layer.
The above article from KENOS official website (http://www.kenos-diecasting.com/) kenosblog1508
The original address: http://www.kenos-diecasting.com/news_show_98.html, reproduced please specify.
没有评论:
发表评论