The melting process design, casting method design arid heat treating process design of the nodular iron gear box housing used for HEXIE D2C model 7 200 kW electric locomotive which was required to have low temperature impact toughness were intrnrlnmd. By through process experiment and trial production the final production process which could si ably obtain qualified castings was determined as follows:induction furnace melting + cored wire injection nodularizing + sub-temperature annealing. As the result of adopting above production process, the low temperature toughness of the gear box housing reached the European standard:-40 ℃ impact toughness ≥15 J/mm2;the casting process yield ≥85% and the casting rejection rate ≤3%. Both the experiment and hatch production showed that adopting some low annealing temperature was more beneficial to improve the low temperature toughness.%介绍了有低温冲击要求的和谐D2C型7 200 kW电力机车用球铁齿轮箱体的熔炼、铸造和热处理工艺设计,通过工艺试验和试生产,确定了能够稳定获得合格铸件的工艺方案是:感应炉熔炼+喂丝球化处理+亚温退火处理.采用这一工艺生产的齿轮箱体的低温韧性达到了欧标要求,-40℃的冲击韧度≥15Jhm2,工艺出品率≥85％,废品率≤3％试验和批量生产实践表明,较低的退火温度更有利于获得高的低温韧性.
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