The Formation of Spherical Graphite in Cast Irons with the Economy of Rare Earth Metals

Author Name(s): German N. Safronov, Nikolay N. Safronov, Lenar R. Kharisov
Author Email: ln271@mail.ru

Abstract

The article suggests an alternative technological process for obtaining high-strength cast irons, based on a synergetic complex of casting and metallurgical factors affecting cast iron in the stages of its melt preparation and crystallization in the mold, as well as resource-saving with use of the process of self-propagating high-temperature synthesis. The proposed process opens new prospects in the production of quality cast iron castings with the solution of problems of saving material and energy resources. Scientifically, these technological processes are the basis of a new paradigm – compaction in graphitized cast irons without modifying its liquid state.

Introduction

Cast iron is the cheapest machine-building material with good casting properties, machinability with cutting, wear resistance, high resistance to alternating loads. All this causes the wide use of cast irons as a structural material. The main problem of cast irons, which determines their consumer qualities, is the morphology of graphite inclusions, which significantly affects the basic properties of cast iron, primarily on strength and ductility, characterizing cast iron as a structural material. Many of the operational properties of gray cast iron depend on the size and number of graphite inclusions. It is obvious that comparatively small inclusions with vortex plates with their uniform distribution ensure higher operating properties of cast iron. Large graphite plates with relatively straight pointed edges serve as sources of cracking, leading ultimately to the destruction of the part or product as a whole. In many large-sized inclusions of graphite, characteristic internal cracks are observed in the form of longitudinal discontinuities of continuity caused by growth stresses. A significant level of growth stress also serves as the reason for the pronounced loose package structure of the growth hillocks. The negative effect of graphite on the decrease in the indexes of mechanical properties decreases with increasing its compactness.

Conclusion

Thus, the proposed technological processes for the production of graphitized cast irons, which promote the formation of compact graphite forms without modifying processing of the liquid state, open new prospects in the production of quality cast iron castings with the solution of problems of saving material and energy resources. Scientifically, these technological processes are the basis of a new paradigm – compaction in graphitized cast irons without modifying of its liquid state.

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