磁粉檢測(cè)對(duì)鋼管內(nèi)表面質(zhì)量的不良影響研究

Study on Negative Effect by Magnetic Particle Detection on Steel Pipe Inner Surface Quality

摘要: 以某廠(chǎng)生產(chǎn)的無(wú)縫鋼管經(jīng)磁粉檢測(cè)后管端內(nèi)表面出現(xiàn)凹陷為例, 通過(guò)對(duì)凹陷的宏觀(guān)形貌、金相組織、硬度等檢驗(yàn)分析, 得出了凹陷產(chǎn)生的原因是磁粉探傷機(jī)電極表面氧化后與鋼管內(nèi)表面接觸不良, 局部區(qū)域電阻過(guò)大, 導(dǎo)致鋼管內(nèi)表面發(fā)生熔化, 同時(shí)產(chǎn)生電弧燒傷鋼管內(nèi)表面;并提出了防止鋼管磁粉檢測(cè)過(guò)程中產(chǎn)生管端凹陷的建議

Abstract: The seamless steel tube made by a certain manufacturer has got depressions on its inner surface at the end as occurring after being detected with magnetic particle process. Taking such a tube as the sample,the depression area is analyzed via tests concerning macro-morphology,metallographic structure and hardness,etc. The analysis result reveals how the said depression is developed. It is because that during the detection process,the electric pole surface of the machine gets oxidized,and thus causes poor contact with the tube surface,which results in excessively-high electric resistance in local area,and the tube inner surface is in turn melted,and electric arc occurs to get the surface burnt. Based on the above mentioned facts,relevant suggestions are proposed to prevent occurrence of the defective tube-end depressions during the magnetic particle detection operation.