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RESEARCH AND DEVELOPMENT OF NEW ROLL MATERIALS WITH MULTI-COMPONENT SYSTEM

多组分体系新型卷材研发

基本信息

批准号：
06555223
负责人：
MATSUBARA Yasuhiro
金额：
$ 1.6万
依托单位：
KURUME NATIONAL COLLEGE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

The purpose of this research project is to research and develop the new roll materials with high wear resistance and performance for rolling and pulverizing mills using multi-component alloys. The type of carbide precipitaion in multi-component alloys are MC,M_2C,M_7C_3 and M_3C.Morphology of the MC carbide is classified into three of petal-like, nodular and coral-like types. The M_2C carbide is classified into two of lamellar and coarse plate-like types, and the morphology of M_7C_3 is rod-like or ledeburitic types. The type and morphology of carbides varied remarkably depending on chemical compossition of alloy, particularly C and V,and Mo and W expressed by a parameter of tungsten equivalent (W_<eq>), when Cr and Co contents are constant. However, they are not changed by cobalt. Region of chemical compositions in which each type of carbide precipitates is expressed by simple equations in relation to the contents of C vs. V and W_<eq>.Solidification of the alloy with MC and M_2C eute … More ctic carbides takes the following process ; austenite (gamma) phase or MC carbide precipitates firstly as a primary phase, then L*gamma+MC eutectic reaction occurs and the solidification finishes the eutectic reaction of L*gamma+M_2C.In the alloy where MC and M_7C_3 carbides coexist, the solidification begins with precititation of primary gamma phase or MC carbide, followed by the L*gamma+MC eutectic reaction, and finally the L*gamma+M_7C_3 eutectic reaction. As for the alloy with MC,M_7C_3 and M_2C eutectic carbides, the solidification sequence is as follows ; L_0*gamma+MC+(L_1), L_1*gamma+M_7C_3+(L_2) and L_2*gamma+M_2C.The continuous cooling transformation (CCT) curve of the multi-component alloy was found to consist of two curves of pearlite and bainite transformations separated far about 200K betweem them. The positions of both transformation curves are largely changed by the chemical composition and austenitizing temperature.By selecting a combination of alloying elements, therefore, the multi-component alloys with different matrix structures can be obtained. Generally, an increase in C content delays the pearlite transformation and advances the bainite transformation and lowers the M_S temperatures. Higher austenitizing temperature shifts CCT curve to the long time side and this improves the hardenability of the alloy.Co decreases the hardenability of multi-component alloy because Co promotes both of the pearlite and banite transformation. However, Co does not reduces the M_S temperature so much. V delays both of pearlite and banite transformation and the delaying degree of the pearlite transformation is more than the bainite transformation.In the case of heat treatment of these alloys, the secondary precipitation hardening occurs greatly by tempering at around 800K,and there the retained austenite reduces almost less than 3%. The maximum hardness obtained by the secondary hardening ranges from HV 900 to HV 1050. It is made clear that the increase in C and V contents and the austenitizing temperature must increase the tempering tempering temperature to obtain the maximum hardness. Less

本研究计画之主要目的为研究开发多元合金制米尔斯机用高耐磨性及高性能之新型轧辊材料。多元合金中碳化物的析出类型为MC、M_2C、M_7C_3和M_3C，MC碳化物的形态分为花瓣状、球状和珊瑚状三种。M_2C碳化物分为片层状和粗片状两种，M_7C_3碳化物为棒状或莱氏体状。当Cr和Co含量一定时，碳化物的类型和形态随合金化学成分的变化而变化，特别是C和V，以及用W_（W_）表示的Mo和W<eq>。然而，它们不会被钴改变。每种碳化物析出的化学成分范围与C、V、W含量的关系用简单方程表示。<eq>MC和M_2C型合金的凝固 ...更多信息 CTIC碳化物采取以下过程：在MC和M_7C_3碳化物共存的合金中，凝固过程首先析出初生γ相或MC碳化物，然后发生L * γ + MC共晶反应，并完成L* γ + M_2C共晶反应，最后是L* γ +M_7C_3共晶反应。对于含有MC、M_7C_3和M_2C共晶碳化物的合金，其凝固顺序为：L_0*gamma+MC+（L_1），L_1 *gamma+M_7C_3+（L_2），L_2 *gamma+ M_2C。发现该多元合金的连续冷却转变（CCT）曲线由两条珠光体和贝氏体转变曲线组成，它们之间相距约200K。合金的化学成分和凝固温度对两种转变曲线的位置有很大的影响，通过选择合金元素的组合，可以得到具有不同基体结构的多元合金。碳含量的增加使珠光体转变延迟，贝氏体转变提前，M_S温度降低。高的奥氏体化温度使CCT曲线向长时间一侧移动，提高了合金的淬硬性，Co的存在使多元合金的淬硬性降低，这是因为Co促进了珠光体和贝氏体的转变。而Co的加入对M_S温度的降低作用不大。V对珠光体相变和贝氏体相变均有延迟作用，且珠光体相变的延迟程度大于贝氏体相变，在800K左右回火时，合金发生了明显的二次沉淀硬化，残余奥氏体量几乎减少到3%以下。通过二次硬化获得的最大硬度范围为HV 900至HV 1050。结果表明，提高C、V含量和淬火温度，必须提高回火温度，才能获得最大硬度。少