Low Pressure Die Casting Molding Process Numerical Simulation Of Shell Of Tanks Used To High Voltage Switchgear

GIS is one of substation series production having international advanced technology and one of its critical parts is aluminium alloy shell of tanks cast by low pressure die casting unitarily.At present, sand casting is adopted in our country mostly, which makes finished product ratio of shell of tank low and cost high.Therefore, aiming to resolving unitarily low pressure die casting production problem of large-scale shell of tanks used to high-voltage switchgear, regarding shell of tanks typed 076 as object, low pressure die casting unitarily is used and its process is optimized in the study in order to improve finished product ratio of shell of tank and inherent and physical quality and comprehensive mechanical property.For raising their molding characteristic, the design project of shell of tank lying tube-annular- gap- typed casting system is adopted firstly so that the problem of its filling difficulty is resolved. low pressure die casting process is optimized by numerical simulation. On the basis of the characteristics of low pressure die casting fluid flow, low pressure die casting filling and solidification process of aluminum alloy shell of tanks used to high-voltage switchgear is studied by casting process numerical simulation software named Z - Cast.In the foundation of simulation, the average rising speed formula of metal alloy liquid on the top of rising liquid tube is deduced, that is to say,lgv_filling =213.54- 19.31gV + 20.31gS + 25.31gh-43.931gT_casting - 12.981gT_moldApplication indicates that the formula is in relatively good agreement with practical production, which can guide the process design of filling process of low pressure die casting.According to the simulation results, the creation reasons of defaults in the process of solidification are analyzed so that forecasting methods of the defaults are put forward and reasonable process parameters of aluminum alloy shell of tanks used to high-voltage switchgear are ascertained, that is to say, the mold temperature is or so 300 ℃, the casting temperature is or so 700 ℃, the sand temperature is or so 150 ℃, rising liquid pressure is 0.0300MPa, rising liquid time is 35 seconds, filling pressure is 0.0550MPa, filling time is 44 seconds, maintaining pressure time is 2 seconds, increasing pressure is 0.0720MPa, increasing pressure time is 5seconds, maintaining increasing pressure time is 50 seconds and the cold time in air is 80 seconds.Shell of tanks used to high-voltage switchgear cast by low pressure die casting process optimized in the project, heat treatment, that is to say, 535℃(±5℃)x5h+quenching in water+ 170℃(±5℃)×8h makes the body of shell of tank of AlSilOMg has such mechanical properties as σ_b =245MPa, δ₅ =4.3%, HB=110.5, the mechanical properties of shell of tanks have satisfiedDIN1725 standard. In virtue of lossless probing and infliction pressure experiments,it shows that the interiors of Shell of tanks have not evident defaults and the leakproofhess adds up to technique require,what is more, process optimized in the project is consistent with practical production.