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標題: AISI 430 不銹鋼之熱處理對氫擴散的影響
Annealing Effects on The Hydrogen Diffusing and Corrosion
作者: 李正弼
Lee, Cheng Pi
Contributors: 顏秀崗
S.K.Yen
國立中興大學
關鍵字: Hydrogen diffusing;AISI 430 Stainless Steels;Annealing
氫擴散;AISI 430不銹鋼;熱處理
日期: 1997
Issue Date: 2012-09-04 11:45:57 (UTC+8)
Publisher: 材料工程學研究所
摘要: 摘 要:本研究以AISI 430不銹鋼為
材料,探討在不同高溫處理溫度下,其微結構的變化對氫擴散(hydrogen
diffusion)以及抗腐蝕性的影響。材料以陰極充氫進行氫擴散試驗可觀察
在不同高溫熱處理下,微觀結構的變化及其對氫擴散之影響,並可進行擴
散遲滯(time-lag)或穿越(breakthrough time)時間、擴散係數和表面氫
濃度的量測並以掃描式電子顯微鏡(SEM)、光學顯微鏡(OM)、X-ray繞射儀
來分析微結構變化。 結果發現430不銹鋼之高溫熱處理在600℃
~700℃時,因為熱處理後的晶粒成長,晶界比例變小,使擴散路徑減少而
造成擴散速率的降低,此階段氫擴散係數之減小被認為是因晶界間為主要
擴散途徑逐漸由晶格擴散效應所取代。然而800℃的熱處理發現晶格擴散
的效應逐漸被因(110)擇優取向加速的晶格擴散所取代,所以氫擴散速率
逐漸增快。在900℃熱處理下的晶粒相當大且擇優取向的趨勢十分顯著,
氫擴散速率則更快,因此可以認定在900℃熱處理下,在晶格間會因擇優
取向而產生一快速擴散的捷徑供氫通過,而此時的晶界反而扮演阻礙晶格
擴散的角色,且又因為900℃的晶粒更大故晶界比例更小,所以氫擴散速率
大幅提升 . 利用電化學極化測試可發現430不銹鋼在0.6M NaCl水溶液
中受到腐蝕時呈現典型的孔蝕現象,在熱處理溫度介於600~700℃時,材
料腐蝕較為嚴重,而在800~900℃時顯示出略佳的抗蝕能力,由不銹鋼之
敏化資料可發現抗蝕能力變差是因為敏化現象的發生。
AbstractThe effect of
microstructure on the hydrogen diffusion and corrosion
resistanceof AISI 430 stainless steel has been investigated at
annealing temperature873K ~ 1173K . Through hydrogen diffusion
tests , the time-lag(tl) ,breakthrough time(tb) , diffusivity
and sublayer concetration were derived . Then , microstructure
variations were analyzed by scanning electron microscopy(SEM) ,
optical microscopy(OM) , and X-ray diffractometer(XRD) . It was
found that the diffusivity was a little reduced from 1.74(as-
received) to about 1.4 at 873 ~ 973K . It was considered that
hydrogen diffusion path of grain boundaries was partly replaced
by that of lattice but with grain boundary as a barrier because
the grain growth reduce the ratio of grain boundary to lattice .
At 1073 ~1173K , the diffusivity was increased to 2 ~ 4.5 on the
contrary . XRD showed a high ratio of (110) preferred
orientation and SEM showed a further grain growth especially at
1173K Polarization tests in 0.6M NaCl aqueous solution which
were used to evaluate the corrosion property of 430 stainless
steel showed a typical type of pitting . Pitting corrosions
became more seriously within 873~973K due to sesitizing effect ,
but at 1073 ~1173K , the pitting potential(Epit) showed a little
higher than that of the as-received .
Appears in Collections:[依資料類型分類] 碩博士論文

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