【摘要】 利用中频感应熔炼炉制备了球墨铸铁,采用X-ray衍射仪、光学显微镜、场发射扫描电镜和电子万能试验机分别研究了配分时间对球墨铸铁的微观结构、组织形貌和力学性能的影响。结果表明:淬火无配分的球墨铸铁由马氏体和残留奥氏体组成。随着配分时间的增加,奥氏体发生回火转变和等温淬火转变两个过程。配分时间较短时,球墨铸铁的奥氏体含量增加,在配分时间为10 min时达到最大值。配分时间进一步增加,奥氏体由于分解为下贝氏体和碳化物含量逐渐降低。同时球墨铸铁的抗拉强度和伸长率随着配分时间的增加也发生非单调的变化。配分时间为120 min时,抗拉强度达到最大值,约为1503 MPa;伸长率在配分时间为60 min时达到最大值,约为2.61%。更多还原

【Abstract】 The ductile cast irons were prepared by melting process in an intermediate frequency induction furnace and effect of partitioning time on microstructure and mechanical properties of the ductile cast irons was studied by means of X-ray diffraction,optical microscope and field emission scanning electron microscopy,respectively. The results show that the microstructure of the ductile cast irons quenched without partitioning treatment is composed of martensite and retained austenite. With the increasing of partitioning time,the retained austenite is decomposed by tempering and bainitic transformation manner. When the partitioning time is short,the content of austenite increases and reaches a maximum value at about 10 min. With increasing the partitioning time further,the content of austenite decreases due to the decomposition into the lower bainite and carbides. Meanwhile,the tensile strength and elongation of the ductile cast irons also change non-monotonically with partitioning time. The tensile strength reaches a maximum value of about 1503 MPa when partitioning time is 120 min and the elongation reaches a maximum value of about 2. 61% when partitioning time is 60 min.更多还原