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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/33692

Title: 銲接參數對異質金屬銲件之應力腐蝕及腐蝕疲勞特性探討
Authors: 陳鈞;蔡履文
Contributors: 國立臺灣海洋大學:材料工程研究所
Keywords: 異質金屬銲接;A508低合金鋼;鎳基填料Alloy 52;顯微組織;銲件接合界面;缺口拉伸試驗;應力腐蝕破裂
Dissimilar metal welding;A508 steel;316L stainless steel;Alloy 52;Microstructure;Weld interface;Notched tensile test;Stress corrosion cracking
Date: 2010-01
Issue Date: 2013-05-13T08:08:04Z
Publisher: 行政院國家科學委員會
Abstract: 摘要:目前國內外應用於核電廠之異質金屬銲接,在低合金鋼管嘴與不銹鋼(或鎳 基合金)管件方面,多使用鎳基合金Inconel 52(GTAW 裸銲條)及152(SMAW 手工電銲條)做為填料,進行銲接或銲補施工。由於異質金屬間存在有組織成分 及機械性質等差異,易使反應器壓力槽及冷卻管路等組件經長時間高溫運轉後, 於界面區域(包含熱影響區及銲道等處)發生應力腐蝕破裂及疲勞劣化等問題, 嚴重危害反應器組件的運轉安全性。在核能工業的眾多研究課題中,填料之選擇 及銲接條件之最佳化,均為改善異質金屬銲件性質的主要方向。銲接參數的改變 對異質金屬銲件顯微組織,以及機械、腐蝕等性質,皆有一定程度之影響,因此 選擇並控制適當的銲接參數,可改善銲件對環境促進破裂效應之敏感性(特別是 回火銲珠製程施工之銲補件),亦為本計畫之主要研究項目。 本研究係以核電廠常用之A508 肥粒鐵系低合金鋼為母材,鎳基合金Inconel 52 為填料進行異質金屬銲接,評估銲接參數(包含回火銲珠製程)對異質金屬銲道 及熱影響區之顯微組織、應力腐蝕及腐蝕疲勞相關特性之影響。對低合金鋼與不 鏽鋼之異質金屬銲件而言,由於應力腐蝕及腐蝕疲勞發生區域多位於低合金鋼 側,故本研究將針對銲件之A508 熱影響區及其鄰近銲道處進行測試。本計畫以二 年為期,第一年進行銲接參數的選擇、熱輸入量對熱影響區之影響,以及異質金 屬銲件在不同腐蝕環境(包含硫化氫及模擬核電廠冷卻水環境)之應力腐蝕試驗 等研究;第二年則針對異質金屬銲件之不同區域,進行在模擬核電廠冷卻水環境 的腐蝕疲勞與300°C 之大氣疲勞試驗。應力腐蝕及腐蝕疲勞等實驗數據,可做為 反應器組件壽命評估之主要依據,而銲接參數對銲件性質之影響亦可提供台電公 司及核能研究所,作為銲接及銲補施工最佳化之參考。
abstract:Dissimilar metal welding is used extensively in nuclear power plants at locations where two different alloys, e.g. ferritic and stainless steels (or nickel-base alloys), are joined. Service failures of piping and nozzles in boiling water reactors (BWR) were observed frequently at such joints. Consequently, the cracking related problems of dissimilar metal welds (DMWs), e.g., stress corrosion cracking (SCC) and corrosion fatigue cracking, have become the major concern of the nuclear industry. In general, sound DMWs can be obtained with nickel-base filler metals by GTAW and SMAW welding methods. Filler metals such as Alloys 52 (GTAW rods) and 152 (SMAW electrodes) have been employed both in new constructions and welding repairs. Numerous programs in the nuclear industry are undertaking to improve DMWs with Inconel 52 (or its modification) filler metal and to assess their performance. Welding parameters are certainly important factors to affect the microstructures in the weld metal (WM) and the heat-affected zone (HAZ), which in turn, alter the susceptibility to environmentally assisted cracking (EAC) of the DMWs. The control of welding parameters is crucial especially for welding repair of the cracked area using the temper-bead technique. Since the cracking is observed regularly in service, the influence of welding parameters on the SCC and corrosion fatigue of DMWs should be investigated thoroughly prior to the field application. In this study, A508 steel (a commonly used alloy in nuclear power plants) and Inconel 52 filler metal are employed to perform dissimilar metal welding. Owing to the fact that most of premature failures in ferritic-austenitic DMWs occurred at the ferritic alloy side in service, the attention is paid to the HAZ and WM adjacent to the A508 side of DMWs for the entire project. This is a two-year proposal and can be divided into two phases according the year of executions. The first-year program deals with the selection of welding parameters (including the parameters used in the temper-bead technique for repairing without the post-weld heat treatment), the effect of heat input on the extent of HAZ, and SCC tests of DMWs under various environments/conditions. The focus of the second-year program is on the corrosion fatigue behavior of distinct regions in DMWs under simulated BWR conditions and 300°C in atmosphere. The results of SCC and corrosion fatigue tests are useful for the lifetime estimation and can be used as guideline for the selection of welding parameters to achieve optimum DMWs for specific requirements.
Relation: NSC99-NU-E002-001
URI: http://ntour.ntou.edu.tw/handle/987654321/33692
Appears in Collections:[材料工程研究所] 研究計畫

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