薄壁小直徑不銹鋼鋼管擴口裂紋原因分析

Analysis of Causes for Flaws of Small-sized Light-wall Stainless Steel Pipe as Occurring during Expanding Process

摘要: 針對航空用薄壁小直徑不銹鋼鋼管(Φ6mm×0.6mm)在擴口過程中(管口擴至Φ9.5mm)容易出現(xiàn)裂紋甚至開裂的問題,利用光學顯微鏡、拉力試驗機及硬度測試儀對其擴口裂紋及加工過程中的硬度積累環(huán)節(jié)進行了試驗分析。研究結(jié)果表明:出現(xiàn)擴口裂紋的不銹鋼鋼管硬度高、晶粒小,同時發(fā)現(xiàn)在加工過程中隨拉拔管徑變小,其硬度有呈線性增長的趨勢。

Abstract: Addressing the fact that as a common case,flaws,even openings are developed with the(Φ 6 mm×0.6 mm)small-sized light-wall stainless steel pipe for aviation purpose,when it is undergoing the expanding process(to get its OD enlarged up to 9.5 mm),the expansion-caused flaws and the processing steps which cause the gradual increase of the hardness of the pipe are analyzed by means of the optical microscopy,the tensile testing machine and the hardness tester. The result of the study identifies that the said flaws normally stay with stainless steel pipes having rather high hardness and small grains,and that the hardness of the pipe is increasing linearly,when its OD is getting smaller along with the drawing operation during the processing.