消失模铸造销轨的断裂失效分析及预防

Fracture Failure Analysis and Prevention of Expandable Pattern Casting(EPC)Pin Rail

利用宏观及微观断口分析、成分分析、力学性能测试对消失模铸造生产的ZG35CrMnSi钢销轨断裂进行失效分析。结果显示,ZG35CrMnSi钢销轨断裂的宏观组织和显微组织含有大量的夹渣,C、Si及Mn超出标准成分上限较多,塑性、韧性不足,从而导致ZG35CrMnSi钢销轨成批脆性断裂。在采用低密度的EPS-PMMA或者PMMA制作模样,采用空心的模样结构或改用砂型铸造工艺,并严格控制该铸件的化学成分,减少夹渣,提高其塑性和韧性,避免脆性断裂。

Fracture failure of ZG35 CrMnSi steel pin rail by EPC was analyzed by macro-scope fractography,microanalysis for fracture,chemical analysis,mechanical properties.The results show that the macro or microstructure of pin rail fracture has plenty of slag inclusion,and chemical compositions exceed upper limit of the standard,resulting in the low plasticity and toughness,which lead to the brittle fracture of ZG35 CrMnSi steel pin rail.It is suggested that EPS-PMMA or PMMA is used as the EPC mold,and the hollow mold is used instead of solid mold,or sand casting process must be used instead of EPC.Meanwhile,the chemical composition of castings must be controlled strictly within specification to reduce the slag inclusion and improve the plasticity and toughness.