SWRCH22A鋼自攻螺釘斷裂原因分析

SWRCH22A鋼自攻螺釘斷裂原因分析Analysis on Fracture Reasons of SWRCH22A Steel Self-Tapping Screws

SWRCH22A鋼自攻螺釘在裝配一天后發(fā)生斷裂，通過(guò)宏觀檢驗(yàn)、化學(xué)成分分析、金相檢驗(yàn)、斷口分析及氫含量測(cè)試等方法，對(duì)其斷裂原因進(jìn)行了分析。結(jié)果表明：螺釘?shù)臄嗔研再|(zhì)為氫致延遲脆性斷裂；螺釘經(jīng)過(guò)熱處理后的顯微組織為回火馬氏體和少量殘余奧氏體，而馬氏體為氫脆敏感組織，且螺釘經(jīng)過(guò)電鍍處理，使得其內(nèi)部氫的質(zhì)量分?jǐn)?shù)高達(dá)0.000 49%，最終導(dǎo)致螺釘于應(yīng)于集中的螺紋起始位置根部發(fā)生氫致延遲脆性斷裂。

Fracture occurred to self-tapping screws of SWRCH22A steel after assembly for one day. The fracture reasons were analyzed through macrographic examination, chemical composition analysis, metallographic inspection, fracture analysis and hydrogen content testing. The results indicate that:the fracture mechanism of screws was delayed brittle fracture induced by hydrogen; the microstructure of screws after heat treatment was mainly tempered martensite and a small amount of residual austenite, and the martensite structure was sensitive to hydrogen brittle; the screws were treated by electroplating, which made the hydrogen content of screws as high as 0.000 49%, and finally caused the delayed brittle fracture of screws induced by hydrogen on the root of thread initiation position where the stress concentrated.

全文下載：https://pan.baidu.com/s/1qYdreEg