螺栓斷裂機制分析及探討

Bolt Failure Cases of Refining and Petrochemical Plant

翁文宏(Wen-Hung Weng)

《石油季刊》 56卷2期 (2020/06) Pp. 59-73

摘要

煉製工場設備中普遍存在螺栓組件，由於螺栓組件繁多，平常維修拆卸組裝又頻繁，容易讓人輕忽它的重要性，稍有不甚就可能會造成洩漏、停機、甚至爆炸等工安事件。本文主要針對煉製工場設備常用來固鎖之螺栓問題做基本介紹，並蒐集多起螺栓斷裂破損案件，探討分析其破損機制。經由案例分析探討，煉油石化廠設備常發生之螺栓斷裂機制包含疲勞破壞、硫化應力腐蝕、氯離子應力腐蝕、鹼性應力脆裂等。其中疲勞裂紋常起始於螺牙根部處，宜靠定期檢測來及早發現，而螺牙製成方式、表面加工狀況及螺栓固鎖程序及扭力大小皆會影響螺栓疲勞壽命；螺栓之硫化應力腐蝕斷裂常導因於材料選用不當或誤用，此宜針對工場製程進行材料劣化機制評估並加強物料管理來避免；至於不銹鋼螺栓之氯離子應力腐蝕裂紋則易發生於保溫層下，其中金屬表面在60℃至110℃之間者，尤需特別留意加強檢查。

關鍵字

螺栓 ； 疲勞 ； 硫化應力腐蝕 ； 氯離子應力腐蝕

並列摘要

Bolt , though a tiny part of equipment , plays an important role for the safety operation of refinery or petrochemical plant. The article reviews the failure analysis cases of bolts fromoil refinery or petrochemical plant and studies these bolts failure mechanisms with optical and scanning electron microscopy (SEM) equipment . The results shows that a few bolt failures were caused by fatigue crack mechanism and the fatigue initial crack usually originated from the bolt root area surface owing to its stress concentrate effect . Among these factors contributed to the fatigue cracking , like the manufacturing method and surface condition of bolt thread, the tightening preload factor has an important influence on the fatigue life of bolt . In some cases ,stress corrosion cracking were found to contribute to the bolt failure , sulfide stress cracking and chloride stress cracking cases are also introduced in this article.

並列關鍵字

Bolt ； Fatigue ； Sulfide Stress Cracking ； Chloride Stress Cracking

參考文獻

Bickford, J. H..An introduction to the design and behavior of bolted joint.

(2010).Guidelines for pressure boundary bolted flange joint assembly, ASME PCC_1.

關凱書,王志文,蔡仁良(2011).ASME PCC_1—2010 《壓力邊界螺栓法蘭連接安裝指南》的解析.壓力容器.28(12),41-47.

Zhao, Hau(1998).Stress concentration factors within bolt-nut connectors under elasto-plastic deformation.International Journal of Fatigue.20(9),651-659.

姜紅超(2006).往復壓缩機螺栓斷裂與疲勞壽命分析.石油化學安全技術.22(6),22-24.