摘要
本文研究了25MnV系三种成分非调质钢在不同奥氏体化温度下保温0.5 h时原奥氏体晶粒长大规律。结果表明,随着加热温度升高,三种实验钢原始奥氏体晶粒尺寸呈阶段长大趋势。25MnV和25MnVNb钢在1 000~1 050℃保温时晶粒明显增大,在1 200℃以上保温时几乎均大于170μm, 25MnVNb晶粒尺寸略低于25MnV,变化规律基本一致。25MnVNbTi钢保温温度在950~1 000℃时奥氏体晶粒尺寸明显增长,1 100℃保温温度下平均晶粒尺寸保持在120μm左右,晶粒尺寸增大幅度小于25MnV和25MnVNb, 1 150~1 200℃保温时原始奥氏体晶粒尺寸明显增大,1 250℃保温时晶粒尺寸未超过150μm, 1 100℃以上保温时晶粒尺寸明显小于25MnV和25MnVNb。三种实验钢奥氏体晶粒尺寸变化规律的不同主要是由钢中不同元素对奥氏体晶粒长大行为综合作用所导致。对于25MnVNb钢,经测算随温度升高达到1 068℃时,Nb元素固溶量达到0.02%,此时钢中Nb元素已全部固溶,NbC对原始奥氏体晶界钉扎作用基本消失,故原始奥氏体晶粒尺寸在该温度范围内明显增加。对于25MnVNbTi钢,低温段VC即快速回溶,导致晶粒长大速度略快,TiN对晶粒有明显细化作用,但由于第二相粒子尺寸增大,体积分数降低,其对奥氏体晶界钉扎作用逐渐减小,故1 150℃以上晶粒尺寸亦明显增大。
This article investigates the growth law of original austenite grains in three components of 25MnV series non quenched and tempered steel at different austenitizing temperatures for 0.5 hours.The results indicate that as the heating temperature increases,the original austenite grain size of the three experimental steels grows in stages.The grain size of 25MnV and 25MnVNb experimental steels significantly increased during insulation at 1000~1050℃,and almost all were larger than 170μm during insulation above 1200℃.The grain size of 25MnVNb was slightly smaller than that of 25MnV,and the change pattern was basically the same.When the insulation temperature of 25MnVNbTi experimental steel is between 950℃and 1000℃,the austenite grain size increases significantly.At the insulation temperature of 1100℃,the average grain size remains around 120μm,and the increase in grain size is smaller than that of 25MnV and 25MnVNb.When the insulation temperature is between 1150 and 1200℃,the original austenite grain size increases significantly.When the insulation temperature is above 1250℃,the grain size does not exceed 150μm,and when the insulation temperature is above 1100℃,the grain size is significantly smaller than that of 25MnV and 25MnVNb.The differences in the variation patterns of austenite grain size among the three experimental steels are mainly due to the combined effects of different elements in the steel on the growth behavior of austenite grains.For the 25MnVNb experimental steel,it has been calculated that as the temperature increases to 1068℃,the solid solution of Nb element reaches 0.02%.At this point,all Nb elements in the experimental steel have been solid solved,and the pinning effect of NbC on the original austenite grain boundaries has basically disappeared.Therefore,the original austenite grain size of the experimental steel increases significantly within this temperature range.For 25MnVNbTi experimental steel,VC quickly dissolves back at low temperatures,resulting in slightly faster grain growth rate.TiN has a significant refining effect on grains,but due to the increase in the size of the second phase particles and the decrease in volume fraction,its pinning effect on austenite grain boundaries gradually decreases.Therefore,the grain size above 1150℃also increases significantly.
作者
郝彦英
任书濠
刘运娜
刘献达
宋仁伯
张朝磊
Hao Yanying;Ren Shuhao;Liu Yunna;Liu Xianda;Song Renbo;Zhang Chaolei(Shijiazhuang Iron and Steel Group Co.,Ltd.,Shijiazhuang 050031,Hebei;School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Carbon Neutrality Research Institute,University of Science and Technology Beijing,Beijing 100083,China)
出处
《河北冶金》
2025年第6期33-39,共7页
Hebei Metallurgy
基金
河北省重大科技成果转化专项项目(22281004Z)
河钢集团重点科技项目计划(HG2022114)。
