冷轧压下率对Fe-10Mn-6Al-0.4C钢微观组织及力学性能的影响  

Effect of cold rolling reduction on microstructure and mechanical properties of Fe-10Mn-6Al-0.4C steel

作　　者：李博宇 柳昆 冯运莉 李涛 王书桓 苏宏东 LI Boyu;LIU Kun;FENG Yunli;LI Tao;WANG Shuhuan;SU Hongdong(College of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,Hebei,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210

出　　处：《钢铁》2024年第4期159-167,共9页Iron and Steel

基　　金：国家自然科学基金资助项目(51974134);河北省科技重大专项资助项目(21281008Z)。

摘　　要：Fe-Mn-Al-C系中锰钢凭借低密度、高强度及高塑性的优点,具有广阔的应用前景。试验以Fe-10Mn-6Al-0.4C为研究对象,热轧后经700℃退火60 min空冷至室温。随后分别以40%、60%和70%的压下率进行冷轧,经冷轧后在750℃退火30 min空冷至室温。采用SEM和EBSD检测冷轧退火后的微观组织演变,使用万能拉伸试验机测量其力学性能。结果表明,冷轧板显微组织由条带状δ铁素体、马氏体(M)、奥氏体(A)和α铁素体组成。退火板显微组织由α铁素体、奥氏体和条带状δ铁素体组成。随着冷轧压下率的增加,退火板组织呈层状结构,且平均晶粒尺寸、细晶占比和奥氏体相成分占比均呈先降低后增加,而再结晶程度则由69%增加至83.5%,退火板GND密度降低。压下率为60%时,奥氏体中GND密度急剧下降,退火板由细小的等轴状奥氏体、α铁素体和条带状δ铁素体组成,铁素体晶粒尺寸呈双峰分布,屈服强度为818.7 MPa,抗拉强度为962.3 MPa,伸长率为34.3%,强塑积达33.01 GPa·%,获得强度和塑性优异组合。拉伸断口显示,压下率为60%的拉伸断口有着密集细小的韧窝,促进了退火板的伸长率,而压下率为40%和70%都有着不同程度的解理台阶,恶化了伸长率。控制压下率结合短时退火可降低工艺成本前提下形成层状结构,从而提高材料力学性能。Fe-Mn-Al-C medium manganese steel has broad application prospects due to its low density,high strength and high plasticity.In the experiment,Fe-10Mn-6Al-0.4C was used as the research object.After hot rolling,it was annealed at 700°C for 60 min and air-cooled to room temperature.Subsequently,they were cold rolled at 40%,60%and 70%reduction ratio,respectively.After cold rolling,they were annealed at 750°C for 30 min and air-cooled to room temperature.The microstructure evolution after cold rolling and annealing was detected by SEM and EBSD,and the mechanical properties were measured by universal tensile testing machine.The results show that the microstructure of cold rolled plate is composed of bandedδferrite,martensite(M),austenite(A)andαferrite.The microstructure of the annealed plate is composed ofαferrite,austenite and bandedδferrite.With the increase of cold rolling reduction rate,the microstructure of the annealed sheet is layered structure,and the average grain size,the proportion of fine grain and the proportion of austenite phase composition decrease first and then increase,while the degree of recrystallization increases from 69%to 83.5%,and the GND density of the annealed sheet decreases.When the reduction rate is 60%,the GND density in austenite decreases sharply.The annealed plate is composed of fine equiaxed austenite,αferrite and bandedδferrite.The ferrite grain size is bimodal distribution.The yield strength is 818.7 MPa,the tensile strength is 962.3 MPa,the elongation is 34.3%,and the product of strength and plasticity is 33.01 GPa·%.The combination of strength and plasticity is excellent.The tensile fracture shows that the tensile fracture with a reduction rate of 60%has dense and fine dimples,which promotes the elongation of the annealed plate,while the reduction ratio of 40%and 70%have different degrees of cleavage steps,which deteriorates the elongation.Controlling the reduction rate combined with short-time annealing can form a layered structure under the premise of reducing the proces

关 键 词：中锰钢 压下率 显微组织 力学性能 轻量化 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG335.12[金属学及工艺—金属材料]