Influence of Ti and REE on Primary Crystallization and Wear Resistance of Chromium Cast Iron
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JMEPEG (2019) 28:4002–4011 https://doi.org/10.1007/s11665-019-04088-x
Influence of Ti and REE on Primary Crystallization and Wear Resistance of Chromium Cast Iron Malwina Dojka, Rafał Dojka, Marcin Stawarz, and Andrzej Studnicki (Submitted September 27, 2018; in revised form April 8, 2019; published online May 16, 2019) The article presents the results of primary crystallization, wear resistance and SEM studies of chromium cast iron inoculated with ferrotitanium and rare earth elements as a mischmetal inoculating mixture. Thermal-derivative analysis method was used to conduct studies of primary crystallization in two types of testers, namely ATD-C and ATD-Is, reflecting two different cooling speeds. Wear resistance tests were performed with the use of modified pin-on-disk method on Tribotester 3-POD device, where the samples were moving in circular motion in metal-mineral friction system. Silicon carbide was used as a counter sample. The studies allowed to determine the influence of selected inoculants on the microstructure and wear resistance of the studied samples. All characteristic crystallization temperatures of samples casted into ATD-Is testers increased, as well as wear resistance of each inoculated samples compared to the noninoculated sample. It was proven that TiC and REE compounds are effective inoculants for chromium carbides and that REE compounds can work as underlay for TiC crystallization. Keywords
chromium cast iron, inoculation, mischmetal, titanium, wear
1. Introduction Castings made of chromium cast iron are generally working in hostile conditions, where intense wear is the main problem. In industries such as mining, mineral processing or energetics, chromium cast iron is commonly used for elements exposed to increased wear. Ball and ring mill parts, rollers, transporting elements, abrasion shields, excavator teeth, etc., are parts, whose working conditions are very hard, and for this reason, in order to avoid frequent replacements of those parts, selection of proper material is vital to achieve the longest possible life span of the casting (Ref 1, 2). There are many materials that have better wear resistance than chromium cast iron, but their price is much higher. One of the reasons why chromium cast iron is such an attractive material is its excellent ration between wear resistance and production cost. But what if wear resistance of selected chromium cast iron is insufficient for our needs? One of the possibilities is to use alloying elements different than chromium, which will form different carbides, resulting in enhancement of wear resistance, but such action will highly increase the cost of production. This article is an invited submission to JMEP selected from presentations at the 73rd World Foundry Congress and has been expanded from the original presentation. 73WFC was held in Krakow, Poland, September 23-27, 2018, and was organized by the World Foundry Organization and Polish FoundrymenÕs Association. Malwina Dojka, Rafał Dojka, Marcin Stawarz, and Andrzej Studnicki, Department of Found
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