发明授权
- 专利标题: Method of producing spheroidal graphite cast iron article
- 专利标题(中): 生产球墨铸铁制品的方法
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申请号: US848022申请日: 1997-04-28
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公开(公告)号: US5876523A公开(公告)日: 1999-03-02
- 发明人: Hideaki Nagayoshi , Seishin Ueda , Kouhei Imanishi
- 申请人: Hideaki Nagayoshi , Seishin Ueda , Kouhei Imanishi
- 申请人地址: JPX Tokyo
- 专利权人: Hitachi Metals, Ltd.
- 当前专利权人: Hitachi Metals, Ltd.
- 当前专利权人地址: JPX Tokyo
- 优先权: JPX8-132818 19960429
- 主分类号: C21D5/00
- IPC分类号: C21D5/00 ; C22C37/04
摘要:
A method of producing a spheroidal graphite cast iron article containing at least one pearlite stabilizing element selected from the group consisting of Mn, Cu, Sn, Sb and Pb and having a double layer structure which comprises a surface layer portion and an inner portion. The surface layer portion has a matrix 60% or more of which is ferrite phase and a thickness of at least 0.5 mm. The inner portion has a matrix substantially comprising pearlite phase. The method comprises: (1) heat-treating a starting spheroidal graphite cast iron at a temperature which transforms a whole part of a matrix of the starting spheroidal graphite cast iron substantially to austenite phase; (2) slowly cooling the austenitized spheroidal graphite cast iron at a cooling rate (5.degree. to 20.degree. C./min) which allows in a subsequent step the surface layer portion to be ferritized before the inner portion starts to be pearlitized; (3) holding the cooled spheroidal graphite cast iron at a temperature (710.degree. to 770.degree. C.) which allows the surface layer portion to be first ferritized and subsequently allows the inner portion to be pearlitized while preventing the ferrite phase of the surface layer portion from being transformed to another; and (4) cooling the spheroidal graphite cast iron thus transformed immediately after completion of the pearlitization of the inner portion.
公开/授权文献
- US5401519A Low calorie composite sweetener and a method of making it 公开/授权日:1995-03-28
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