球墨铸铁管过度孕育的危害研究

Hazards of Excessive Inoculation on Ductile Cast Iron

离心球墨铸铁管在生产和使用过程中常见管体开裂缺陷,导致铸管报废。通过对开裂部位进行分析,发现其共同特征是局部高硅、石墨呈细小高密度分布(点状石墨)。本文通过试验,比较系统地分析了点状石墨的形成原因,指出球墨铸管在生产过程中局部过度孕育导致石墨呈点状分布,这是造成球墨铸铁管异常开裂的主要原因,其危害性较大。同时通过提高喷粉控制精度,完善喷粉设备和喷粉控制程序,确保管模布粉均匀,可以有效避免过度孕育缺陷的出现,稳定铸管质量。

The tube cracking defect is common in the production and use of centrifugal ductile cast iron pipe,which causes the cast pipe scrapping.Through the analysis of cracking position,it was found that the commom feature is local high-silicon,and the tiny and high density distribution of graphite（dot graphite）.Through experiments,this article systematical analyzed the reason of dot graphite forming,and pointed out that the local excessive inoculation in the production of the ductile cast iron pipe caused the graphite dotted distribution,which was the main reason of the ductile iron pipe abnormal cracking.Meanwhile,through improving the pulverized coal conrrol precision,perfecting the equipment and control program of the powder injectionto assure the uniform distribution of the pipe mould powder,it was effective to avoid the appearance of the local excessive inoculation and stabilize the cast tube quality.