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齿条、锒条、活动导轨、摇臂、立柱等杆类铸件,加工要求高,光洁度一般在(?)6～(?)8,加工表面不允许存在砂眼、气孔和缩松缺陷,并要求在零件长度方向上性能均匀。这类铸件的材质,牌号多为HT20-40,HT25-47,HT30-54。为防止渣孔和气孔的产生,浇注温度较高,一般在1350°—1380℃。铸件的重量多在200公斤以下。考虑到碳当量低,浇注温度高,铸件重量小的特点,采用冒口补缩是必要的。如果从传统的顺序凝固原则出发,采用比例法设计冒口,可将冒口安放在铸件的几何热节(一般为杆件的中部)处。这种工艺,常在铸件的热节上表面产生缩凹,冒口根部缩松,
Racks, racks, rails, rocker, column and other rod castings, processing requirements, the finish is generally (?) 6 ~ (?) 8, the processing surface is not allowed to have trachoma, porosity and shrinkage defects, and requirements Uniform performance in the length of the part. Casting materials, grades and more HT20-40, HT25-47, HT30-54. In order to prevent the generation of slag holes and pores, pouring temperature is higher, generally at 1350 ° -1380 ℃. Casting more than 200 kilograms in weight. Taking into account the low carbon equivalent, pouring temperature is high, the casting weight is small, the use of feeder riser is necessary. From the traditional order of solidification principle, the use of proportional design of riser, riser can be placed in the casting geometric heat Festival (usually the middle of the rod) Department. This process, often in the hot section of the casting surface shrinkage concave, riser root shrinkage,