Wear by hard particles

High chromium white irons are ferrous based alloys containing 11–30 wt-% chromium and 1.8–3.6 wt-% carbon, with molybdenum, manganese, copper, and nickel sometimes added as additional alloying elements. The microstructure of these alloys typically consists of hard primary and/or eutectic carbides in a matrix of austenite or one of its transformation products. The presence of hard alloy carbides results in excellent abrasion resistance and, consequently, these alloys are commonly used for materials handling in the mining and minerals processing industries. Alloy content, solidification parameters, and thermal processing can dramatically alter the microstructure that is produced, and this in turn can influence the properties and hence performance of white iron alloys during service. This review outlines the development of the microstructure in high chromium white irons through solidification and thermal processing. The metallurgical effects of conventional processing techniques are discussed, and ad...

Microstructure-property relationships in high chromium white iron alloys

Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic, eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect to the macrostructural transitions of the castings, solidification paths, and resulting microstructures when poured with varying superheats. Completely equiaxed macrostructures were produced in thick section castings with slightly hypereutectic compositions. High-stress abrasive wear tests were then performed on the various alloys to examine the influence of both macrostructure and microstructure on wear resistance. Results indicated that the alloys with a primarily austenitic matrix had a higher abrasion resistance than similar alloys with a pearlitic/bainitic matrix. Improvement in abrasion resistance was partially attributed to the ability of the austenite to transform to martensite at the wear surface during the abrasion process.

Solidification structure and abrasion resistance of high chromium white irons

https://hal.archives-ouvertes.fr/hal-01666708/document

George T. Eldis

Papers

Abrasive wear of white cast irons