Development of a New ATD-P Tester for Hard Wear Resistant Materials

2022

Materials

Chromium cast irons have gained a well-settled position among wear-resistant materials where a low manufacturing cost is one of the key factors. The wear properties of these alloys are commonly improved by the addition of carbide-forming inoculating elements such as Ti, V, B, etc., allowing the formation of underlays for the precipitation of both M7C3 carbides and austenite. On the other hand, Sr may work as a surface-active element that adsorbs on the surface of the growing crystal, inhibiting its growth. This mechanism may support the M7C3 nucleation process. The experiment was conducted on near-eutectic chromium cast irons with 20% of Cr and 2.5–3% of C. Different amounts of strontium were used as the microstructure modifier. The improvement of carbides’ stereological parameters and collocation resulted in the improvement in functional properties—wear resistance and impact strength without a significant increase in hardness as well as a decrease in carbide phase. Two types of wear studies with a modified pin-on-disc method and tests in reciprocating motion of samples in the metal-mineral system were performed. The results showed that addition modification with Sr can increase the impact strength of the alloy. EDS analysis of the samples provided results similar to hypoeutectic Al-Si alloys modified with strontium.

Section: Methodsmentioning

confidence: 99%

“…The presented work is part of a project implemented in the department [1][2][3]26]. The experimental castings were obtained by filling the ATD-P tester mold described in other authors' work [1,26]. The scheme of the mold and model of the casting with marked sampling places for individual tests are presented in Figure 4.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of Carbide Growth by Sr in High-Alloyed White Cast Iron

2022

Materials

“…To maintain a uniform pouring temperature and avoid undercooling (solidification) of the alloy in the ladle, the temperature was also measured in the mold used to make samples for impact strength and abrasive wear resistance tests. For this purpose, ATD-P and ATD-Pi molds were designed [ 19 ]. Figure 2 presents the scheme of the mold and a 3D casting model with marked sampling locations for individual tests.…”

Section: Methodsmentioning

confidence: 99%

Bifilm Defects in Ti-Inoculated Chromium White Cast Iron

Stawarz

2020

Materials

In recent years, white chromium cast iron has gained a well-settled position among wear-resistant materials. In recent times, chromium cast iron samples containing titanium have attracted attention. In cast iron samples, titanium combines with carbon and forms TiC particles, which may be form a crystallization underlay for eutectic M7C3 carbides and austenite. Accordingly, the inoculation process occurring in the crystallizing alloy should result in the proper, regular distribution of fine eutectic chromium carbides in the austenitic matrix. The presented research was conducted on 20% Cr hypoeutectic white cast iron with the addition of 0.5, 1, and 2% of Ti. Ti inoculation and the presence of TiC allowed for superior wear properties to be obtained. However, the conducted study revealed a significant decrease in the impact strength of examined alloys, especially for the cast iron samples with a high amount of Ti, in which the TiC compounds agglomerated. Titanium compounds accumulate in clusters and their distribution is irregular. Most of the TiC compounds were transported by the crystallization front into the center of the castings, where micropores were formed, meaning they were no longer effective crystallization underlays. In the authors’ opinion, the agglomerate formation is strictly connected with the appearance of bifilm defects in the casting microstructure. The conducted research shows how an incorrect volume of an additive may have negative influences on the properties of the casting. This is a vital issue not only from a technological point of view, but also for economic reasons.

“…Application of TDA method allowed registration of cooling (T ¼ f ðtÞ) and crystallization (T 0 ¼ dT dt ) curves. Analysis of both curves was conducted according to theories of prof. Stanisław Jura (Ref [15][16][17][18][19], Polish authority in the field of crystallization examination. Analysis allowed authors to designate characteristic temperatures of examined melts crystallization.…”

Section: Materials and Methodology Of The Studiesmentioning

confidence: 99%

Influence of Ti and REE on Primary Crystallization and Wear Resistance of Chromium Cast Iron

J. of Materi Eng and Perform

Stawarz

et al. 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 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.