摘要
在20CrNiMoH钢中添加了0.03%的Nb,通过末端淬火试验、物理化学相分析以及热膨胀试验等研究Nb对试验钢在950和1200℃淬火时对其淬透性的影响。结果表明:当淬火温度为950℃时,Nb主要在析出相中,由于Nb的添加细化了晶粒,含铌钢的淬透性低于不含铌钢。当淬火温度为1200℃时,NbC析出相发生回溶,Nb固溶到奥氏体晶粒中,含铌钢的淬透性高于不含铌钢。热膨胀试验结果表明固溶Nb具有降低试验钢的临界冷却速度,提高Ms点以及推迟珠光体铁素体转变,扩大马氏体贝氏体相区的作用,从而提高其淬透性。
0.03%Nb was added to 20CrNiMoH steel.The effect of Nb on the hardenability of the experimental steel when quenched at 950℃ and 1200℃ was studied through end-quenching test,physicochemical phase analysis and thermal expansion test.The results show that when the quenching temperature is 950℃,Nb is mainly in the precipitated phase,and due to the addition of Nb refining the grain,the hardenability of the niobium containing steel is lower than that of the niobium free steel.When the quenching temperature is 1200℃,NbC precipitates undergo re dissolution,and Nb dissolves into austenitic grains,which leads to the hardenability of the niobium containing steel is higher than that of the niobium free steel.The results of the thermal expansion test show that the solution of Nb can reduce the critical cooling rate of the experimental steel,increase the martensitic transformation temperature Ms,delay the pearlitic ferrite transformation,and expand the martensite bainite phase zone,thereby improving its hardenability.
作者
陈文杰
尉文超
王毛球
朱心昆
何肖飞
CHEN Wen-jie;YU Wen-chao;WANG Mao-qiu;ZHU Xin-kun;HE Xiao-fei(Faculty of Materials Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China;Institute for Special Steels,Iron and Steel Research Institute Limited,Beijing 100081,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2023年第7期134-140,共7页
Transactions of Materials and Heat Treatment
