Si固溶强化工艺在QT500-7支架上的应用
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摘要
通过对平衡轴中间支架浇注系统及冒口布置分析和多批次产品加工后不同位置的硬度及金相组织检测,发现铸件硬度差较大,在中间部位设置了2个补缩冒口,却形成了较大热节,导致铸件两端与中间部位冷却速率不同造成产品硬度不均匀,切削加工困难,加工成本增高。采用Si固溶强化铁素体球墨铸铁工艺生产QT500-7支架,经多批次取样检测,不同位置的硬度差变小,基体组织中的珠光体体积分数都为5%,硬度均匀,使切削加工变得容易,降低了加工成本,成功地解决了重型汽车平衡轴中间支架硬度不均匀导致加工困难的问题,为生产高质量、低成本及轻量化的汽车铸件创造了条件。
Through the analysis of the casting system and riser layout of the middle bracket of the balance shaft and the hardness and metallographic examination of the different locations after processing of multi-batch products,it was found that the hardness difference of the casting was large,and two feeders were set in the middle part. However,a large thermal section was formed,which resulted in different cooling rates at the two ends and the middle of casting. It leaded to non-uniform hardness of the product,the difficulty in cutting and increasing processing costs. The QT500-7 bracket manufactured by using Si solid solution strengthened ferrite nodular cast iron technology,had smaller hardness difference after multiple batch sampling tests. The volume fraction of pearlite in the matrix was 5% and the hardness was uniform. The processing became easy and the processing cost was reduced. The problem of difficulty in processing due to the uneven hardness of the middle bracket on balance shaft of the heavy-duty vehicle was successfully solved. It set the stage for producing high quality,low cost and lightweight automotive castings.
Through the analysis of the casting system and riser layout of the middle bracket of the balance shaft and the hardness and metallographic examination of the different locations after processing of multi-batch products,it was found that the hardness difference of the casting was large,and two feeders were set in the middle part. However,a large thermal section was formed,which resulted in different cooling rates at the two ends and the middle of casting. It leaded to non-uniform hardness of the product,the difficulty in cutting and increasing processing costs. The QT500-7 bracket manufactured by using Si solid solution strengthened ferrite nodular cast iron technology,had smaller hardness difference after multiple batch sampling tests. The volume fraction of pearlite in the matrix was 5% and the hardness was uniform. The processing became easy and the processing cost was reduced. The problem of difficulty in processing due to the uneven hardness of the middle bracket on balance shaft of the heavy-duty vehicle was successfully solved. It set the stage for producing high quality,low cost and lightweight automotive castings.
引文
[1]朱张校,姚可夫.工程材料[M].北京:清华大学出版社,2012.
[2]GB/T 1348-2009,球墨铸铁件国家标准[S].
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[4]詹兵.Si C在球墨铸铁生产中的使用方法及效果[J].现代铸铁,2017,(03):37-40.
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[8]韩清环,冀建勇,李建平,等.稳定生产高强度4缸球墨铸铁曲轴的研究[J].现代铸铁,2018,(02):19-26.
[9]邵壮,刘景峰,胡玲海.EA211曲轴动平衡的改善方法[J].现代铸铁,2018,(02):34-37.
[10]李文彬.防止覆砂铁型铸造气缸体铸件产生气孔的方法[J].现代铸铁,2018,(02):38-40.
[2]GB/T 1348-2009,球墨铸铁件国家标准[S].
[3]王建东,王成刚,刘景峰,等.壳型填丸工艺生产空心球墨铸铁曲轴的试验[J].现代铸铁,2017,(03):26-29.
[4]詹兵.Si C在球墨铸铁生产中的使用方法及效果[J].现代铸铁,2017,(03):37-40.
[5]黄彪,龚文邦,高辉武,等.高Si球墨铸铁及其应用发展[J].现代铸铁,2018,(01):29-32.
[6]彭凡,尤国庆,郭亮.QT900-2高强韧厚大断面球墨铸铁的研究[J].现代铸铁,2018,(01):33-37.
[7]陈建国,王小伟,王国华.高Si球墨铸铁磨煤机摇臂的生产工艺[J].现代铸铁,2018,(01):38-40.
[8]韩清环,冀建勇,李建平,等.稳定生产高强度4缸球墨铸铁曲轴的研究[J].现代铸铁,2018,(02):19-26.
[9]邵壮,刘景峰,胡玲海.EA211曲轴动平衡的改善方法[J].现代铸铁,2018,(02):34-37.
[10]李文彬.防止覆砂铁型铸造气缸体铸件产生气孔的方法[J].现代铸铁,2018,(02):38-40.