ABSTRACT

A bimetallic composite roll with the cladding layer of high-speed steel (HSS) and the roll core of ductile cast iron (DCI) was manufactured by the electroslag remelting cladding (ESRC) technology, and the changes in the graphite morphology, matrix structure, and mechanical properties of the DCI core before and after the ESRC process were compared. The DCI core was first heated to a very high temperature and then cooled down to room temperature during ESRC which led to a deteriorative graphite morphology with a low spheroidisation rate, a large size, and a nonuniform distribution and also caused a solid-state phase transformation of the matrix structure from lamellar pearlite + few carbides to bainite + large amounts of carbides. Based on the changes of graphite sphericity, matrix structure, carbides content, the tensile strength and impact toughness of DCI before and after the ESRC process changed from 458 MPa, 3.02 J/cm² to 417 MPa, 5.74 J/cm², respectively.

摘要

采用电渣重熔熔覆（ESRC）技术制造了高速钢（HSS）熔覆层和球墨铸铁（DCI）辊芯的双金属复合轧辊，石墨形态、基体结构、比较了 ESRC 工艺前后 DCI 磁芯的机械性能。DCI 核心首先被加热到非常高的温度，然后在 ESRC 期间冷却到室温，这导致石墨形态恶化，球化率低，尺寸大，分布不均匀，并导致固态相变基体结构从层状珠光体+少量碳化物到贝氏体+大量碳化物。基于石墨球度、基体结构、碳化物含量的变化，^{分别为 2}至 417 MPa、5.74 J/cm ²。