The Development And Quality Control Of BL18T Cast Iron Cylinder Block

BL18T engine is made with all aluminum, which is rather difficult with thestagnant cast aluminum technology in China. The blank can only be supplied by aEuropean corporation. Brilliance has faced several problems in mass production,such as delayed turnover and delivery of aluminum alloy cylinder, no on-timefeedback and improvement in cast quality, and high cost of delivery and purchase,and thus entrusts237#workshop of Harbin Dongan Auto Engine Co., Ltd. fordesigning and producing cast iron cylinder block.In view of current design and production in the workshop, according to the pointof view that head loss of the casting mechanism mainly occurs to the sprue, therunner and the filter net. The paper calculates that μ shall be0.40～0.50of thebottom gating system appropriate for step gating.The paper designs two casting methods with reference to the casting manualand domestic experience. Anycasting software is used for simulated casting test andoptimization of the casting system. The casting system is improved through practice,and the appropriate sprue-runner-gate area ratio of Italian FA static pressure moldingline for producing complex cylinder block shall be AMain Sprue: AResistance Sprue: AMainDistributor Sprue: ARunner: ABottom Gate=2.0:1:1.1:3.0:2.0. The flow loss coefficient of theBL18T cylinder block μ shall be0.50.The casting system improves core making and core assembly. Theconvex-concave fireproof groove is used between the main core, in replace of thesecondary sprue and the ingate between the main core. The high-temperatureproperties of the coated sand are strictly controlled, which eliminates the possibilityof core drilling. The elastic high-temperature-resistant gasket is equipped betweenthe mould and the core, and the air exhaustion hole is equipped outside of the mould.The air is exhausted toward the non-casting area, which eliminates the pore. Poor conditioning before furnace delivery is the main cause of carbide hard spot.The melting process can be improved for first-time success. Recarburizing inoculatorand silicon-barium-calcium inoculator is used in decant inoculation, which eliminatesbase carbide hard spot. The chemical constitution shall be controlled that Si shall be2.3%～2.4%, C shall be3.15%～3.25%, and Si/C shall be0.71～0.76. It can be ofhelp in obtaining complete ferrite for lengthened life of the milling tool, with increasein its productivity from500～600pieces to more than1000pieces.