In recent years,the core properties have become an important index to measure the internal quality of ductile iron cooling staves.Some projects require heart tensile strength Rm≥350 N/mm2,elongation A ≥8％.Heart metallographic spheroidization rate ≥ 70％,ferritic content ≥ 80％.However,because the ductile iron cooling staves belongs to thick and large castings,the core properties are not stable due to the influence of solidification characteristics,cooling rate and alloying elements,etc.,and usually cannot meet the requirements of the technical agreement.In this paper,the reasons for the low performance of the heart are analyzed,and the improvement measures are put forward.
维普
万方数据