Effect of Microstructures on Working Properties of Nickel-Manganese-Copper Cast Iron

Andrzej Janus,Bartłomiej Samociuk,Jacek Chęcmanowski,Daniel Medyński

doi:10.3390/met8050341

Abstract

In the paper, the effects, on basic usable properties (abrasive wear and corrosion resistance), of solidification (acc. to the stable and non-stable equilibrium system) and transformations occurring in the matrix during the cooling of castings of Ni-Mn-Cu cast iron were determined. Abrasive wear resistance was mainly determined by the types and arrangements of high-carbon phases (indicated by eutectic saturation degree), and the kinds of matrices (indicated by the nickel equivalent value, calculated from chemical composition). The highest abrasive wear resistance was found for white cast iron, with the highest degree of austenite to martensite transformation occurring in its matrix. Irrespective of solidification, a decrease of the equivalent value below a limit value resulted in increased austenite transformation, and thus, to a significant rise in hardness and abrasive wear resistance for the castings. At the same time, corrosion resistance of the alloy was slightly reduced. The examinations showed that corrosion resistance of Ni-Mn-Cu cast iron is, too a much lesser degree, decided by the means of solidification of the castings, rather than transformations occurring in the matrix, as controlled by nickel equivalent value (especially elements with high electrochemical potential).

Highlights

High demands concerning abrasive wear and corrosion resistance are imposed on cast iron castings designed for machine parts operating in hard conditions; the development of materials that guarantee longer trouble-free operation becomes the priority.In abrasion conditions, abrasive wear resistance depends, to a large degree, on the hardness of the castings
A wide range of chemical compositions of the examined alloys is reflected in distinct differentiation between modes of solidification and the transformations occurring during cooling, and in the properties of the castings
The highest resistance to abrasive wear was demonstrated by the cast iron with the highest hardness, resulting from a high degree of chilling and from a partial transformation of austenite to martensite

Summary

Introduction

High demands concerning abrasive wear and corrosion resistance are imposed on cast iron castings designed for machine parts operating in hard conditions; the development of materials that guarantee longer trouble-free operation becomes the priority.In abrasion conditions, abrasive wear resistance depends, to a large degree, on the hardness of the castings. High demands concerning abrasive wear and corrosion resistance are imposed on cast iron castings designed for machine parts operating in hard conditions; the development of materials that guarantee longer trouble-free operation becomes the priority. All structural components increasing material hardness most often increase its resistance to abrasive wear [1,2,3,4,5,6]. From this point of view, chilled martensitic cast iron seems to be the most favourable. High-alloy materials with one-phase matrices are characterised by increased corrosion resistance. Within the group of casting alloys, a typical representative of such a material is austenitic cast iron Ni-Resist, containing 14 to 36% of nickel [1,8]

Methods

Results

Conclusion