采用山西球铁生铁+钛铁生产 CA498半激冷Cr-Ni-Mo合金灰铸铁凸轮轴,从凸轮轴轴颈上取样检查显微组织,发现由大量初生奥氏体和奥氏体+D型石墨共晶体组成,奥氏体在随后的固态相变中转变成珠光体.分析认为,适当提高w(C)量,有利于避免凸轮轴时归位产生显微缩松.经测定,该凸轮轴轴颈部位的硬度为235-255 HB,直径30 mm单铸试棒的抗拉强度为255-285 MPa,满足客户要求.%The CA498 semi-chilled Cr-Ni-Mo alloyed gray iron camshaft was produced with Shanxi nodular iron pig iron + Ti-Fe alloy as melting charges. Microstructure examination was conducted by sampling from the shaft neck of the camshaft and found that the structure was eulectic consisted of large amount primary austenitc+D-type graphite, and in later solid phase transformation the austenile changed into pcarlitc. It' s considered after analysis that properly increasing C content would beneficial to avoid shrinkage porosities occurring in the base circle section of the cam. The inspection showed that hardness of camshaft neck was of 235-255, tensile strength of separately cast lest bar with diameter of 30 mm was of 255-285 MPa that meeting client' s requirements.
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