毕业设计（论文）-铸造夹杂物对挂舵臂机械性能的影响.doc

铸造夹杂物对挂舵臂机械性能的影响
摘要
钢中的非金属夹杂物对钢质量和性能的影响,不仅取决于夹杂物数量的多少,而且与夹杂物的类型、形状、大小、变形行为和分布情况有着密切的关系。材料的损伤演化一般都是从夹杂物与基体界面处开始的,研究材料夹杂物与基体周围的应力、应变场分布对材料的失效是有重要意义的。
本文介绍了夹杂物的分类、来源、形态分布和形成过程,并且采用ANSYS有限元分析软件,对在大型挂舵臂铸钢件试样中出现的不同类型、形状、分布、数量的夹杂物建立了有限元模型,计算在单向拉伸变载荷作用下,夹杂物及其周围基体等效应力场的分布。结果表明:试样中的应力场分布与夹杂物的数量、种类、形态、夹杂物之间的距离、材料的弹性模量等有密切的关系,其中夹杂物和基体的弹性模量的差距及夹杂物的形态、距离对试样内的应力集中程度及最大应力影响最显著。
通过严格控制挂舵臂化学成分、冶炼工艺和热处理工艺,可消除缩松、裂纹等缺陷,在钢中加入微量的稀土元素,能够细化晶粒,改善钢中夹杂物的形态和分布, 使夹杂物由长条形转变为球形,由分布于晶界转变为弥散分布于晶内,显著提高钢的质量和机械力学性能。
关键词:挂舵臂,ANSYS,夹杂物,最大应力
The Impact of Mixed Sundries on the Mechanical Performance of Rudder Arm
ABSTRACT
Impact of non-metallic sundries contained in steel on the quality and performance of the steel depends not only on the quantity of these sundries, but also their type, shape, size, deformation behavior and. Material damage evolution generally starts at the interface between sundaries and matrix. So researching the stress of sundries against surrounding matrix and the distribution of stress field is very significant for the problem of inferior material
This paper introduced the classification, source, species distribution and the formation process of sundries, and built finite element model with ANSYS finite element analysis software. Then we calculate stress field distribution of sundries and surrounding matrix under the load of uniaxial tension. The results show: stress distribution have a close relationship with the number, type, shape and the distance of sundries. Anyway, the most significant impact on the stress concentration degree and the maximal stress is the difference between the elastic modulus in sundries and matrix , the shape of these sundries and the distance between them..
To eliminate shrinkage and cracks defects we can take measures such as controlling position of the rudder arm, smelting process and heat treatment process. Adding a trace amount of the rare earth element in the steel can refine crystalloid grains and improve the shape and distribution of sundri