【摘要】：對新開發(fā)大截面貝氏體塑料模具鋼SDP2在極低冷速下的過冷奧氏體連續(xù)冷卻轉變過程和相變動力學進行了研究。采用DIL805A高精度差分熱膨脹儀測量SDP2鋼線膨脹行為,利用SEM分析冷卻轉變產(chǎn)物;根據(jù)JMA公式計算SDP2鋼貝氏體相變激活能和Avrami指數(shù)。結果表明,SDP2鋼過冷奧氏體連續(xù)冷卻過程包含珠光體、貝氏體和馬氏體轉變,而無鐵素體轉變;當冷速大于0.02℃/s時,轉變產(chǎn)物以下貝氏體或馬氏體為主;小于0.02℃/s時,以上貝氏體或粒狀貝氏體為主,并出現(xiàn)珠光體。SDP2鋼貝氏體轉變的激活能為117 k J/mol,SDP2鋼在不同冷速下貝氏體轉變動力學指數(shù)Avrami指數(shù)n≈2~3,經(jīng)分析計算所得的Avrami指數(shù)值所對應的顯微組織形態(tài)和實驗所觀察到的顯微組織相符合。
[Abstract]:The continuous cooling transformation process and transformation kinetics of undercooled austenite at very low cooling rate for the newly developed large-section bainitic plastic die steel SDP2 were studied. The linear expansion behavior of SDP2 steel was measured by DIL805A high precision differential thermal expansion instrument, the cooling transition product was analyzed by SEM, and the activation energy and Avrami exponent of bainite transformation of SDP2 steel were calculated according to JMA formula. The results show that the continuous cooling process of supercooled austenite of SDP2 steel consists of pearlite, bainite and martensite transformation, but no ferrite transformation, and when the cooling rate is greater than 0.02 鈩，

本文編號：2335898