Composite Metal Product

Abstract

A centrifugally cast composite metal product having an axis of rotational symmetry and a mass of at least 5 kg, comprises a host metal and insoluble solid refractory particles of & refractory material in a non-uniform distribution throughout the host metal. The particles have a density that is within 30% of the density of the host metal at its casting temperature.

Description

TECHNICAL FIELD[0001]The present disclosure relates to a method of centrifugal casting of a composite metal product, the finished product typically ranging in mass from 20-5,000 kg, having a host metal matrix, typically a ferrous metal matrix, and comprising outer surface layer, nominally 1-20 mm thick, of hard, insoluble refractory particles for enhanced wear resistance.[0002]The present disclosure also relates to centrifugally cast composite metal products.[0003]In the context of the present disclosure, the term “refractory particles” is understood to include particles of high melting point carbides and / or nitrides and / or borides of any one or more than one of the nine transition metals titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten dispersed in a tough host metal, which acts as a binder phase. Each of these refractory particles is a particle of a refractory material and is referred to herein as a “refractory material”. Typically, the ...

AI Technical Summary

Benefits of technology

This patent describes a new method for making solid particles of refractory materials that are insoluble in the host metal at the casting temperature and after solidification. This is different from previous methods that added soluble heat-retaining alloys to the host metal. The new method involves adding particles of ferro-niobium, ferro-titanium, ferro-tungsten, or ferro-niobium-titanium-tungsten to the melt under inert conditions to prevent oxidation. This results in a microstructure with significantly fewer hard, insoluble refractory carbides and reduced solubility of the added elements in the host metal, which improves physical and chemical properties such as toughness and response to heat treatment.

Problems solved by technology

As a consequence, in these systems, the volume % of hard, insoluble refractory carbides in the microstructure is substantially reduced and the dissolved tungsten and / or molybdenum and / or chromium may adversely influence the physical and chemical properties of the host metal at room temperature by an unknown amount, (e.g. reduced toughness and a different response to heat treatment).

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