本文針對JIS B1051 10.9及12.9系列風力機破損螺栓從外觀目視檢視、破斷面微觀組織、材料元素成份及腐蝕物分析等多方面探討風力機螺栓破損原因。結果顯示10.9及12.9系列螺栓斷裂面皆為延性斷裂(凹槽狀)，成份以鐵Fe、碳C為主，另發現微量硫S(0.33 at.%)存在；因無過多的腐蝕硫S元素，故推論螺栓的破壞斷裂是由於外應力大於螺栓的降伏強度而導致螺栓斷損。

In this study, the damage of bolts of wind turbine is discussed from the aspects of visual inspection, microstructure of fracture surface, material composition and corrosive analysis of JIS B1051 10.9 and 12.9 series of wind turbine. The results show that 10.9 and 12.9 series of bolt fracture surface are ductile fracture (dimple), t and composed majority of iron (Fe), carbon (C) and minority of sulfur S (0.33 at.%). In fact, there is no excessive amount of corrosive sulfur (S) element, so the bolt damage from the fracture surface could be inferred that the external stress, which was greater than the yield strength of the bolt.