螺絲經過鍍鋅處理後容易導入氫原子或氫離子，氫原子或氫離子會藉由擴散而從鍍鋅層進入工件內部，並在晶界處生成氫分子聚集，對材料造成脆性破壞，通常會在使用環境中一段時間後才會發生破壞，因此又稱為延遲破壞(delay fracture) 。本研究採用10B21低碳硼鋼進行淬火回火熱處理，探討其熱處理後顯微組織及機械強度，以及將其鍍鋅螺絲成品進行烘烤除氫與改變淬火回火條件探討對於常溫及低溫下抵抗氫脆的能力。
經過淬火回火後之抗拉強度不論在260°C或320°C回火各30及 60分鐘都能夠高於1200MPa，顯微組織為回火麻田散體及細微雪明碳體中間夾雜再結晶肥粒體，較高溫回火可以觀察到類似塊狀的波來體結構。
本研究用10B21低碳鋼做成鍍鋅螺絲會發生嚴重氫脆，因此選擇以烘烤除氫及改變微觀組織為主要方法去測試可否有效抵抗，實驗結果顯示於215˚C下烘烤能有助於將氫原子或氫離子排出工件外，烘烤8小時於常溫及低應力雖不會發生氫脆破壞，但卻無法在低溫及高應力下使用；16小時的烘烤在低溫及高應力下使用則有良好效果，但礙於成本考量有執行上的困難。因此又改變熱處理條件，發現如前述所提到的回火麻田散體及細微雪明碳體中間夾雜再結晶肥粒體組織能有效成為捕捉氫原子的氫陷阱(hydrogen trap)，縱使QT260-30及QT320-30兩組回火條件的機械性質都是屬於氫脆高危險群(HRC≧32, Tensile strength ≧1250MPa)，常溫使用下氫脆現象在回火溫度260˚C持續30分鐘還是會發生但機率很低，而在回火溫度320˚C持續30分鐘則完全沒有破壞現象，推測試前述高溫回火中的組織能有效捕捉氫離子使之不會對螺絲造成脆性破壞；低溫環境下(-15˚C、30 ˚C)改變熱處理條件之螺絲能完全抵抗氫脆。

In this study, hydrogen was introduced into the screw through the process of electroplating, which made the HE fracture happened. To improve it, we used two methods including baking and increasing tempering temperature. 10B21 zinc-plating screw with quench tempering heat treatment(tempering condition: Austenitizing 950°C for 30minutes then water quenching, tempering 220°C for 60minutes then air cooling. ) was my as-received screws. In the first part, we baked screw at 215°C for 0, 8, 16hours and conducted hydrogen embrittlement test. In second part, we increasing tempering temperature including 260°C and 320°C for 30minutes then conducted hydrogen embrittlement test. The results of experiment of two methods improving the hydrogen embrittlement considerably. Baking efficiently drives out the hydrogen atoms and ions and increasing tempering time changes the microstructure of screws which increasing the hydrogen traps in the screws likes interphase of fine recrystallization ferrite (Sorbite) and lamellar cementite and the tempering carbide.

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