Effect of Repeated Tempering on Hardness and Retained Austenite of High Chromium Cast Iron Containing Molybdenum

<p>High-Chromium White Cast Iron is a material highly used in mining and drilling shafts for oil extraction, due to its high wear resistance. However, because of the austenitic matrix found in the as-cast state, an adequate heat treatment cycle is necessary. This paper studies the effects of different cooling media after a destabilization treatment on the microstructure, hardening and abrasion resistance behaviors of a hypoeutectic high chromium white cast iron. The results show that although air cooling followed by immersion in CO2 can effectively reduce the retained austenite, this is not enough to transform completely the retained austenite into martensite. The low retained austenite percentages improve bulk hardness, but they decrease the abrasion resistance of the high chromium cast iron. The best combination of hardness and wear resistance was found in the samples cooled in air, due to the percentage of retained austenite and a moderate precipitation of chromium carbide.</p>

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Effects of Heat-Treatment on the Microstructure and Wear Resistance of a High-Chromium Cast Iron for Rolls

Advances in Materials Science and Engineering ◽

10.1155/2016/9807685 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Zhi-hong Guo ◽

Fu-ren Xiao ◽

Su-ling Lu ◽

Han-yun Li ◽

Bo Liao

Keyword(s):

Wear Resistance ◽

Cast Iron ◽

Retained Austenite ◽

Tempered Martensite ◽

High Chromium ◽

High Chromium Cast Iron ◽

The Matrix ◽

The Impact ◽

Chromium Cast Iron ◽

Martensite Matrix

The variations of microstructure and mechanical properties of a high-chromium cast iron for rolls were studied from as-cast to the final heat treatments. Results show that the as-cast microstructure of the HCCI consists of M7C3carbide, M23C6carbide, martensite matrix, and retained austenite. The large dendritic M7C3carbide surrounds the matrix, and the M23C6carbide is mainly distributed in the matrix. Part of M23C6carbide transforms to M7C3carbide and is dissolved in austenite during austenization at 1020°C. Thus, the amount of M23C6carbide decreases, whereas that of M7C3carbide increases after quenching; the highest hardness is also obtained. After tempering, the martensite transforms to a tempered martensite, and some carbide precipitates in the martensite matrix. The hardness also changes from HRC62.1, which corresponds to quenching, to HRC55.2 and HRC56.3, which correspond to once and twice tempering, respectively. However, tempering could improve the impact toughness and wear resistance of the HCCI.

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Hot compression deformation and microstructure evolution of high chromium cast iron based on canning compression

Journal of Materials Science ◽

10.1007/s10853-021-06379-y ◽

2021 ◽

Author(s):

Yanwei Li ◽

Xiaogang Wang ◽

Guofeng Yuan ◽

Peisheng Han ◽

Xiaoyu Zhu

Keyword(s):

Cast Iron ◽

Microstructure Evolution ◽

Hot Compression ◽

High Chromium ◽

Hot Compression Deformation ◽

High Chromium Cast Iron ◽

Compression Deformation ◽

Iron Based ◽

Chromium Cast Iron

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Modeling Corrosion Property of High Chromium Cast Iron under H3PO4 Medium Condition Using Artificial Intelligence

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.150-151.1054 ◽

2010 ◽

Vol 150-151 ◽

pp. 1054-1057

Author(s):

Song Min Zhang ◽

Liu Jie Xu

Keyword(s):

Neural Network ◽

Weight Loss ◽

Cast Iron ◽

Bp Neural Network ◽

Corrosion Property ◽

Corrosion Properties ◽

High Chromium ◽

High Chromium Cast Iron ◽

Chromium Cast Iron ◽

Corrosion Time

The components in slurry pump suffer serious corrosion and abrasion in the phosphorus fertilizer manufacturing process because they undergo corrosion of H3PO4 medium and impact of particles at the same time. Presently, High chromium cast irons are often used to produce the components in slurry pump. In order to reveal the corrosive law, the corrosion properties of high chromium cast iron with 26wt.%Cr content (Cr26) were tested under different H3PO4 medium concentration conditions. Using back-propagation (BP) neural network, the non-linear relationship between the corrosion weight losses (W) and H3PO4 concentration, corrosion time (C, t) is established on the base of the dealing with experimental data. The results show that the well-trained BP neural network can predict the wear weight loss precisely according to H3PO4 concentration and corrosion time. The prediction results reveal that corrosion weight loss rises linearly with increasing corrosion time. The H3PO4 concentration has obvious effect on corrosion property. When H3PO4 concentration is lower than about 0.5mol/L, high chromium cast iron has well resistance to H3PO4 corrosion. However, the corrosion resistance of high chromium cast iron rapidly decreases when the H3PO4 concentration exceed about 0.8 mol/L. It is suggest the high chromium cast iron be used under the condition of H3PO4 concentration of lower 0.8 mol/L.

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