【摘要】：通過焊接熱模擬試驗(yàn),模擬不同熱輸入下Q1100粗晶區(qū)的熱循環(huán)過程。采用示波載荷沖擊試驗(yàn)機(jī)檢測焊接熱模擬試樣的沖擊韌性,結(jié)合OM、SEM觀察試樣的顯微組織和斷口形貌;采用TEM觀察和Lepera腐蝕,研究不同冷速下M-A組元數(shù)量、形貌和分布情況,分析不同熱輸入對粗晶區(qū)顯微組織特征與沖擊韌性的影響規(guī)律。研究結(jié)果表明,隨焊接熱輸入的增大,粗晶區(qū)的組織由板條馬氏體轉(zhuǎn)變?yōu)榘鍡l馬氏體+板條貝氏體的混合組織,最終轉(zhuǎn)變?yōu)榇执蟮牧钬愂象w,原始奧氏體晶粒尺寸逐漸增大;-20℃下的沖擊韌性呈現(xiàn)先增大后減小的趨勢,焊接熱輸入為14.95 k J/cm時(shí),相互交割的馬貝混合組織使Q1100的粗晶區(qū)具有最優(yōu)的韌性。M-A組元的形成和原奧晶粒尺寸的增大是大熱輸入下造成韌性下降的主要原因。
[Abstract]:The thermal cycling process of Q1100 coarse-grained region under different heat input was simulated by welding thermal simulation test. The impact toughness of the thermal simulated welding samples was tested by oscillographic load impact testing machine, and the microstructure and fracture morphology of the samples were observed by OM,SEM. The quantity, morphology and distribution of M-A components at different cooling rates were investigated by TEM and Lepera. The effect of different heat input on the microstructure and impact toughness of coarse crystal region was analyzed. The results show that with the increase of welding heat input, the structure of coarse grain region changes from lath martensite to mixed structure of lath martensite bainite, finally to coarse granular bainite, and the grain size of original austenite increases gradually. The impact toughness at -20 鈩，

本文編號：2375909