钒对高氮轴承钢流变行为和热加工图的影响  

Influence of V on flow behavior and hot processing map of high nitrogen bearing steel

作　　者：黄晓颖 吴明辉 HUANG Xiaoying;WU Minghui(School of Materials Science and Engineering,Northeastern University,Shenyang 110819,Liaoning,China;School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]东北大学材料科学与工程学院,辽宁沈阳110819 [2]东北大学冶金学院,辽宁沈阳110819

出　　处：《钢铁》2024年第11期131-142,共12页Iron and Steel

基　　金：国家自然科学基金资助项目(U1960203)。

摘　　要：高氮不锈轴承钢因其高硬度、优异的强韧性和耐蚀性,成为火箭低温涡轮泵和航空发动机的重要材料。钒微合金化能提高高氮不锈轴承钢的强韧性,但关于其对流变行为和热加工图的影响未见报道。利用Thermecmastor-Z热模拟试验机对0V和0.2V高氮不锈轴承钢进行了单道次热压缩试验,变形温度、应变速率和真应变分别为950~1 200℃、0.01~10 s^(-1)和0.8。结果表明,热压缩前0.2V钢的晶粒更细小、析出相更多,这表明钒微合金化细化了高氮不锈轴承钢的组织,促进了钢中析出相的生成。使用Arrhenius模型和BP神经网络模型预测流变曲线,并评估2种模型的优劣,发现BP神经网络模型对流变应力的预测精度更高。此外,由绝热修正的流变曲线可以看出,钒微合金化提高了高氮不锈轴承钢的流变应力,同时增强了峰值应力之后的应力软化效果。基于动态材料模型建立了0V和0.2V钢应变量为0.4和0.7的热加工图,结果表明,钒微合金化提高了高氮不锈轴承钢在低温、低速率变形过程中的稳定性,提高了稳定区的峰值能量耗散率。通过观察0.01 s^(-1)下不同温度的热变形组织,发现在1 000和1 100℃下0.2V钢的再结晶程度更高,晶粒组织更细小均匀。根据试验钢的热变形行为和热加工图,0.2V高氮不锈轴承钢的最佳热加工参数为1 050~1 125℃、0.01~0.04 s^(-1)和1 125~1 200℃、0.01~0.1 s^(-1)。High nitrogen stainless bearing steel(HNSBS)has become an important material for rocket low-temperature turbopumps and aviation engines due to its high hardness,excellent strength-toughness,and corrosion resistance.Vanadium(V)-microalloying can improve the strength and toughness of high nitrogen stainless bearing steel,but its impact on flow behavior and hot processing map has not been reported.The single-pass hot compression tests of 0V and 0.2V HNSBSs were carried out with a Thermomaster-Z thermo-mechanical simulator.The deformation temperature,strain rate and true strain were 950-1200℃,0.01-10 s^(-1) and 0.8,respectively.The results exhibited that the 0.2V steel had finer grain and more precipitates,indicating that V-microalloying refined the grain structure of HNSBS and promoted the formation of precipitates.The Arrhenius model and BP neural network model were used to predict the flow curves,and the benefits and drawbacks of two models were evaluated.The BP neural network model had a higher accuracy in predicting the flow stress.In addition,the adiabatic corrected flow curves showed that V-microalloying increased the flow stress of HNSBS,while enhancing the softening effect after peak stress.According to the dynamic materials model,the hot processing maps were constructed for 0V and 0.2V steel with strain values of 0.4 and 0.7,which indicated that V-microalloying enhanced the hot working stability of HNSBS at low temperature and low strain rate,and improved the peak energy dissipation rate in the stable zone.By observing the microstructure deformed at 0.01 s^(-1) and different temperatures,the 0.2V steel exhibited higher recrystallization degree,and finer and more uniform grain structure at 1000℃and 1100℃.Based on the hot deformation behavior and hot processing maps of the experimental steels,the optimal hot working ranges for 0.2V steel were 1050-1125℃,0.01-0.04 s^(-1) and 1125-1200℃,0.01-0.1 s^(-1).

关 键 词：高氮不锈轴承钢 钒微合金化 预测模型 绝热修正 热加工图 

分 类 号：TG142.1[一般工业技术—材料科学与工程]