40Cr鋼緊固螺栓斷裂原因分析40Cr鋼緊固螺栓斷裂原因分析Reasons Analysis on Fracture of 40Cr Steel Fastening Bolts 某石化廠管道連接法蘭用40Cr鋼緊固螺栓在使用不到1 a(年)后發(fā)生徑向斷裂。通過宏觀分析、化學(xué)成分分析、光學(xué)顯微鏡和掃描電鏡觀察、硬度測試等方法對螺栓斷裂原因進行了分析。結(jié)果表明: 螺栓在較高應(yīng)力水平下服役, 在應(yīng)力和氫的共同作用下發(fā)生了氫脆斷裂; 導(dǎo)致其氫脆斷裂的主要原因是螺栓在酸洗磷皂化和磷化過程中引入了較多的氫。 The 40Cr steel fastening bolts used for connecting pipe flanges of a petrochemical plant, fractured transversally after less than a year of use. And the fracture reasons were analyzed by means of macroscopic analysis, chemical composition analysis, optical microscopy and scanning electron microscopy observation, and hardness test. The results show that the bolts serviced under high stress level, so hydrogen embrittlement fracture occurred under the combined action of stress and hydrogen. More hydrogen introduced during acid pickling phosphorus and phosphating process were main cause for the hydrogen embrittlement fracture of the fastening bolts.
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