蠕墨铸铁组织及其滚动磨损性能的研究.doc

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摘要: 本文主要研究了蠕墨铸铁的组织形态以及力学性能，对比了在不同蠕化率下的蠕墨铸铁的力学性能以及显微组织，得出了蠕墨铸铁的性能以及蠕化率的关系。同时研究了不同蠕化率的蠕墨铸铁的滚动磨损性能，通过对比蠕墨铸铁、灰铸铁和球铁的滚动磨损亚表面的石墨形态，得出石墨形态和滚动磨损之间的关系。最后分析了滚动磨损的磨屑，了解了整个的磨损过程。通过试验，得出以下结论：

（1）蠕墨铸铁的蠕化率越低，它的力学性能越好，抗拉强度越高，硬度越高。蠕墨铸铁的机械性能接近于球墨铸铁，同时还有良好的铸造性能、切削加工性能和相当高的导热性能。因此，蠕墨铸铁具有良好的综合性能。铸铁中石墨形态和基体组织是决定铸铁性能的最主要的因素。一般情况下，蠕化率越高，基体组织中的铁素体的含量越高，抗拉强度越低，导热性能越好。

（2）不同蠕化率的蠕墨铸铁滚动磨损性能不同。载荷一定时，蠕化率越低，表面越不容易产生裂纹，则滚动磨损性能越好。蠕化率一定时，载荷愈大，表面产生的裂纹就愈多。

（3）经过滚动磨损之后，蠕墨铸铁和灰铸铁中的石墨变得聚集起来，同时石墨变粗。石墨越多，越粗大，分布越不均匀，则力学性能越差。

关键词：蠕墨铸铁  蠕化率  磨损  滚动磨损 石墨形态

 

 

ABSTRACT: This paper studies the compacted graphite cast iron structure and mechanical properties compared in different percentage of vermicular graphite compacted graphite cast iron under the mechanical properties and microstructure properties of compacted graphite cast iron is obtained and the relationship of creep rate. While different rate of compacted vermicular graphite cast iron of rolling wear properties, by comparing the vermicular graphite cast iron, grey cast iron and nodular cast iron wear surface of graphite morphology, come to the relationship between the graphite morphology and wear. Final analysis of the wear debris, understanding of the wear process. Through the test, reached the following conclusions:

( 1 ) Lower rate of compacted graphite cast iron, its good mechanical properties, high tensile strength, high hardness. Mechanical properties of compacted graphite cast iron close to nodular cast iron, as well as good casting performance, cutting performance and very high thermal conductivity , therefore, vermicular graphite cast iron with good performance. Cast iron graphite morphology and performance of cast iron matrix structure was decided the most important factor. Under normal circumstances, rate to creep higher, matrix of ferrite content in high tensile strength , the lower the heat conductivity, the better.

( 2 ) The different rate of compacted vermicular graphite cast iron roll and wear properties are different. When the load is constant, creeping lower, less prone to cracks on the surface, rolling wear properties as possible. When the rate of creep, loads more, more surface cracks.

( 3 ) After passing through the rolling wear, vermicular graphite cast iron and grey cast iron together, while graphite thicker. Graphite, the more, the more coarse and less evenly distributed, worse mechanical properties.

Key words:  vermicular graphite cast iron；creep rates；abrasion；rolling wear；graphite morphology