發(fā)布時間：2018-11-11 00:55

【摘要】：為了研究800MPa級低合金高強鋼焊接粗晶區(qū)的組織轉變規(guī)律,采用熱模擬的方法,應用L78RITA相變熱膨脹儀模擬了實驗用鋼的兩次焊接熱循環(huán)過程,對應的焊接線能量約為20kJ/cm。建立了該鋼的奧氏體連續(xù)加熱轉變曲線(TTA),并對組織、硬度和熱膨脹曲線進行分析,結果顯示,實驗用鋼一次熱循環(huán)粗晶區(qū)組織為板條馬氏體和貝氏體,硬度為318HV,當第二次熱循環(huán)峰值溫度(Tp2)為1000℃時,第一次熱循環(huán)后的組織發(fā)生完全重結晶,得到細小的貝氏體組織,硬度下降,當Tp2為900℃時發(fā)生部分重結晶,硬度最低(239HV),當Tp2為800℃時,在晶界和晶內相界生成鏈狀分布的M-A組元,而Tp2小于A′c1時發(fā)生回火作用,M-A組元分解并析出碳化物。實驗用鋼的熱影響區(qū)未出現組織遺傳現象,因此為了更準確判斷組織轉變類型,應結合TTA曲線對焊接熱影響區(qū)組織轉變進行分析。
[Abstract]:In order to study the microstructure transformation of the coarse grain zone of 800MPa low alloy high strength steel, the thermal expansion process of two welding cycles of experimental steel was simulated by L78RITA phase transformation thermal expansion instrument. The corresponding welding line energy was about 20kJ / cm ~ (-1). The austenite continuous heating transformation curve (TTA),) was established and the microstructure, hardness and thermal expansion curves of the steel were analyzed. The results showed that the microstructure of the primary thermal cycle of the steel was lath martensite and bainite, and the hardness was 318HV. When the peak temperature of the second thermal cycle (Tp2) is 1000 鈩，

本文編號：2324052