外加亚微米氧化物对高速钢铸态组织的影响  

Effect of externally added sub-micron oxides on as-cast microstructure of high-speed steel

作　　者：肖志霞 徐梦凯 吴新财 徐瑞 梁国欣 冯建航 XIAO Zhixia;XU Mengkai;WU Xincai;XU Rui;LIANG Guoxin;FENG Jianhang(School of Materials Science and Engineering,Hebei University of Technology,Tianjin 300132,China;Tianjin Meiteng Technology Co.,Ltd.,Tianjin 300381,China;Xuanhua Construction Machinery Development Co.,Ltd.,Zhangjiakou 751000,Hebei,China)

机构地区：[1]河北工业大学材料科学与工程学院,天津300132 [2]天津美腾科技有限公司,天津300381 [3]宣化工程机械开发有限责任公司,河北张家口751000

出　　处：《钢铁》2025年第2期141-152,共12页Iron and Steel

基　　金：河北省自然科学基金资助项目(E2023202233)。

摘　　要：高速钢因其优异的红硬性、高耐磨性和适当的韧性,被广泛应用于切削刀具、轧辊、冷作模具等领域。然而,作为高碳高合金钢,高速钢因凝固过程的元素偏析不可避免地形成粗大的网状共晶碳化物,这严重降低了高速钢的后续加工性能和使用寿命。研究表明,向钢中引入弥散分布的亚微米级氧化物可显著改善其微观组织并提高钢的强韧性。基于此,以AISI M2(M2)高速钢为对象,利用中间合金法向M2钢中引入亚微米Al_(2)O_(3)颗粒,详细分析了外加亚微米氧化物对高速钢铸态组织的影响规律。结果表明,引入的Al_(2)O_(3)颗粒在高速钢中以1μm左右的Al_(2)O_(3)-MnS复合球状形式存在,大部分氧化物颗粒弥散分布于初生枝晶间,少数位于枝晶干上。在高速钢凝固过程中,初生δ相倾向于以这些外加的亚微米氧化物质点为形核核心,从而促进了枝晶组织细化,并改善了基体中Cr、W、Mo和V元素的显微偏析。高速钢中引入亚微米Al_(2)O_(3)颗粒后并不改变钢中共晶碳化物的类型,但形成了更多呈短纤维状的共晶M_(2)C,此外,共晶碳化物的相对含量降低。随着中间合金加入量的增加,高速钢中非金属颗粒的数量密度增加,同时颗粒的平均直径下降,这表明非金属第二相颗粒能够更加均匀弥散分布于钢中,从而有利于高速钢铸态组织的进一步细化。High-speed steel(HSS)is widely used in cutting tools,rolls,cold work molds and other fields due to its excellent red hardness,high wear resistance and appropriate toughness.However,as a high-carbon high-alloy steel,HSS inevitably forms coarse network eutectic carbides due to elemental segregation during solidification,which seriously reduces the subsequent machinability and service life of HSS.Numerous studies have shown that oxide particles with suitable size can refine the microstructure and improve the strength and toughness of steel.Based on this,sub-micron Al_(2)O_(3) particles were introduced to M2 high-speed steel(HSS)by master alloy,and the effect of sub-micron oxides on the as-cast microstructure of HSS were investigated.The results show that the introduced Al_(2)O_(3) particles were present in the form of Al_(2)O_(3)-MnS composite of about 1μm,and most of these particles diffusely distributed in the interdendritic regions,and several located on the dendritic stems.During solidification of HSS,the primaryδ-phase tended to nucleate on these submicron oxide,which promotes the refinement of dendrites and improved the microsegregation of Cr,W,Mo and V elements.The introduction of submicron Al_(2)O_(3) particles into HSS does not change the types of eutectic carbides,but more short fibrous eutectic M_(2)C appeared in HSS,meanwhile the content of eutectic carbides in HSS was reduced.As the addition of master alloy increased,the number density of non-metallic particles in HSS increased,while the average diameter of the particles decreased.This indicates that the non-metallic second phase particles can be more uniformly dispersed in HSS,thus facilitating further refinement of the as-cast structures of HSS.

关 键 词：高速钢 Al_(2)O_(3)颗粒 共晶碳化物 微观偏析 非金属粒子 弥散分布 枝晶 形核核心 

分 类 号：TG142.1[一般工业技术—材料科学与工程]