Study On Microstructure And Properties With V Alloying And RE Compound Modification O F Ni-Cr-Mo Cast Iron

With the development of grinding technology, all kinds of large-scale equipment emerging continuously, which need to use a variety of large roll to work. As the result, the requirement increased higher. The roll is the main component of all kinds of grinding, crushing, pressing machinery equipment, and its quality related to the using and safety for grinding, crushing, pressing etc. the quality of products and equipment. Because of high hardness wear-resistant materials are brittle material, its toughness is low. It may be serious accidents such as partial of the external layer peeling off or breaking down the roll in the process. To improve its toughness of the material field is always the pursuit of the goal.This paper mainly used Ni-Cr-Mo cast iron for roll as the research object, using vanadium alloying and rare earth compound modification treatment of two kinds of treatment methods, by using metal mold casting simulating centrifugal composite casting, to study the V and RE composite modifier effect on mechanical properties and microstructure of cast iron. The mainly addition of alloying is V, the mainly addition of compound modification are RE-Al and RE-Al-V. Analysis and discussed the affecting about the microstructure and mechanical properties under the condition of different amounts of additives. The results show:The presence of vanadium in Ni-Cr-Mo cast iron alloying-treatment, can make the austenitic and carbide of Ni-Cr-Mo cast iron getting obvious refinement effect, enhance the continuity of the matrix, the plasticity and improve the toughness. In the process of refining the microstructure, the V prompted the transformation from austenite to martensite, and generate the new phase of compounds of V4C3.After RE-Al compound modification treatment, the microstructure of Ni-Cr-Mo cast iron has been improved, the austenite grain got further refinement; Carbide from net broken into strips and more uniform distribution, enhance the continuity of the matrix effectively, improve the plasticity and toughness of cast iron itself; And through the detection of before and after modification treatment, the phase composition did not have the obvious change, to further illustrate the RE-Al metamorphic primarily through promote heterogeneous nucleation effect and modifier elements generated interface enrichment, so as to improve the shape and distribution of microstructure.After RE-Al-V composite modification, significantly changed the coarsening, aggregation and other ledeburite characteristics from the microstructure of the Ni-Cr-Mo cast iron, refine the grain, increase the fine equiaxed austenite, improve the shape and distribution of carbides. At the same time, compared with the V alloying and RE-Al modification, the RE-Al-V compound modification combined the advantages of those two, the modification and the flexibility increasing of Ni-Cr-Mo cast iron is more effective.