Microstructure of impurity phase inclusions in gray cast iron and their composition

D A Boldyrev,S P Nefed’Ev,R N Amirov

doi:10.1088/1757-899x/966/1/012023

Abstract

It is quite difficult to control the content of carbide-forming elements in the production of casting ‘pressure plate’ of gray pearlitic iron grade SCh25 (GOST 1412–85). Therefore, it is necessary to conduct research and analysis of foreign inclusions, the basis of which are ‘uncontrolled’ carbide formers. The analysis of the content of ‘uncontrolled’ carbide-forming elements on the formation of zones with an interdendritic distribution of graphite types D, E (ASTM A247) castings of a pressure plate is carried out. The elemental composition of impurity inclusions is determined. It has been established that ‘uncontrolled’ carbide-forming elements are represented in cast iron in complex carbide-nitride and sulfide-phosphide phases. A conclusion is drawn on the effect of carbide formers on the formation of areas with an interdendritic distribution of graphite. All types of these phases are concentrated to a greater extent within the zones of interdendritic distributions of lamellar graphite D and E. This indirectly confirms the influence of ‘uncontrolled’ carbide-forming elements on their formation.

Highlights

The manufacturer is faced with problems of inconsistency of the structure and material properties of castings with the established regulatory requirements during the development of new foundry products
This is manifested in the presence of ‘uncontrolled’ carbide-forming elements entering the molten iron from waste high-strength steels and noticeably worsening the morphology of the graphite phase in the manufacture of cast iron castings [4,5,6,7,8]
Result and Discussion According to the results of electron microscopy analysis using x-ray spectral microanalysis, it was found that ‘uncontrolled’ carbide-forming elements such as zirconium, vanadium, titanium, tungsten, niobium and molybdenum coming from charge materials are represented in cast iron in complex carbide-nitride and sulfide-phosphide phases

Summary

Introduction

The manufacturer is faced with problems of inconsistency of the structure and material properties of castings with the established regulatory requirements during the development of new foundry products. One of the reasons for such deviations is already observed at the beginning of the processor chain and is associated with the unsatisfactory quality of the charge materials used for melting [1,2,3]. This is manifested in the presence of ‘uncontrolled’ carbide-forming elements entering the molten iron from waste high-strength steels and noticeably worsening the morphology of the graphite phase in the manufacture of cast iron castings [4,5,6,7,8]. Relevant is the study of their influence on the formation of adverse interdendritic distributions of graphite

Methods

Discussion

Conclusion