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利用树脂砂具有很好的保温性能,可以使得最小吃砂量保持在200 mm左右的特点,同时控制原铁液中的碳(3.6%~3.8%)、锰(≤0.1%)、终硅(2.8%~2.9%),控制浇注温度在1 355~1 365℃,并采取型内保温措施(250 h),可以使得某大型船用柴油机体在铸态下得到超过90%的铁素体组织,铸件的抗拉强度≥390 MPa,伸长率≥14%,布氏硬度135~185 HBW,机体缸孔和凸轮轴孔等区域Ⅰ最大残余应力在±50 MPa,内部筋板区域最大残余应力在±50 MPa,可实现正常去应力退火后的效果。
The use of resin sand has good insulation properties, can make the minimum amount of sand to maintain around 200 mm, while controlling the original iron liquid carbon (3.6% ~ 3.8%), manganese (0.1%), the end of silicon 2.8% ~ 2.9%). Controlling the pouring temperature at 1 355 ~ 1 365 ℃ and adopting the in-mold heat preservation measures (250 h) can make the ferrous materials of a large marine diesel engine get more than 90% The tensile strength of the castings is ≥390 MPa, the elongation is ≥14%, the Brinell hardness is from 135 to 185 HBW, and the maximum residual stress in the region I of cylinder bore and camshaft hole is ± 50 MPa. The maximum residual stress in the inner rib region is ± 50 MPa, to achieve the normal stress relief annealing effect.