Effect of Electric Current Pulse on Carbide in Hypereutectic High Chromium Cast Iron

2012 ◽  
Vol 457-458 ◽  
pp. 174-180
Author(s):  
Hua Chen ◽  
Rong Feng Zhou ◽  
Ye Hua Jiang ◽  
Rong Zhou
Keyword(s):  
Cast Iron ◽  
Electric Current ◽  
Current Pulse ◽  
Electric Current Pulse ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Chromium Cast Iron

scholarly journals Effect of Electric Current Pulse on Microstructure and Corrosion Resistance of Hypereutectic High Chromium Cast Iron

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2220 ◽  
Author(s):  
Haiyang Lv ◽  
Rongfeng Zhou ◽  
Lu Li ◽  
Haitao Ni ◽  
Jiang Zhu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Electric Current ◽  
Current Pulse ◽  
Electric Current Pulse ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Microcrack Propagation ◽  
Primary Carbides ◽  
Chromium Cast Iron

The effect of electric current pulse on the microstructure and corrosion resistance of hypereutectic high chromium cast iron was explored. The morphology of carbides in solidification microstructure was observed by an optical microscope and a scanning electron microscope and the composition was determined by an electron probe micro-analyzer. The microhardness of primary carbides and corrosion resistance of samples were also compared. Under the active of electric current pulse, the microstructure of hypereutectic high chromium cast iron was homogenized and its performance improved accordingly. On treatment by electric current, the morphology of primary carbides changed from thick long rods to hexagonal blocks or granular structures. The interlayer spacing of eutectic carbide decreased from ~26.3 μm to ~17.8 μm. Size statistics showed that the average diameter of primary carbide decreased from ~220 μm to ~60 μm. As a result, microhardness increased from 1412 HV to 1511 HV. No obvious microcrack propagation was found at the microindentation sites. The average length of microcracks decreased from ~20.7 μm to ~5.7 μm. Furthermore, corrosion resistance was remarkably enhanced. The average corrosion rate decreased from 2.65 mg/cm2·h to 1.74 mg/cm2·h after pulse current treatment.

Microstructure Refinement of Hypereutectic High Chromium Cast Iron with Electric Current Pulse

2013 ◽  
Vol 690-693 ◽  
pp. 147-152 ◽  
Author(s):  
Hua Chen ◽  
Ling Zhang ◽  
Sheng Ming Wang
Keyword(s):  
Cast Iron ◽  
Electric Current ◽  
Current Pulse ◽  
Pulse Frequency ◽  
Solidification Structure ◽  
Electric Current Pulse ◽  
Electric Voltage ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Chromium Cast Iron

The effect of electric current pulse (ECP) on the solidification structure of hypereutectic high chromium cast iron was studied. The orthogonal array L9 was used to determine the effect of three process parameters of ECP, which were electric voltage, pulse frequency, pulse width. According to the experimental results, the solidification structure of hypereutectic high chromium cast iron was modified from large grains to finer grains with equiaxed crystals, by allowing the ECP to act on liquid.

scholarly journals Change in Primary (Cr, Fe)7C3 Carbides Induced by Electric Current Pulse Modification of Hypereutectic High Chromium Cast Iron Melt

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 32 ◽  
Author(s):  
Baoyu Geng ◽  
Rongfeng Zhou ◽  
Lu Li ◽  
Haiyang Lv ◽  
Yongkun Li ◽  
...  
Keyword(s):  
Cast Iron ◽  
Electric Current ◽  
Current Pulse ◽  
Defect Density ◽  
Micro Hardness ◽  
Electric Current Pulse ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Primary Carbides ◽  
Chromium Cast Iron

In this work, an electric current pulse (ECP) of 500A was applied on a hypereutectic high chromium cast iron (HHCCI) melt before it began to solidify, and the effect of ECP on primary carbides was investigated. The characteristics of the primary carbides were analyzed by X-ray diffraction (XRD), electron probe micro-analyzer (EPMA), transmission electron microscopy (TEM), micro hardness tester, and other techniques. The results showed that ECP not only refined the primary (Cr, Fe)7C3 carbides, but also decreased the average content of Cr in the primary carbides. At the same time, the average value of micro hardness of the primary carbides increased by about 84 Kgf/mm2, which contradicts existing knowledge that hardness increases with an increase in Cr content. XRD analysis showed that the crystal structure of the primary carbides did not change. The results of EPMA indicated that the Cr/Fe ratio gradually decreased from the center to the edges of the carbide particles. Further investigation revealed that the uneven distribution of elements caused by ECP led to an increase in defects (including twins, antiphase boundaries, and dislocations). This increase in defect density is the main reason for the increase in micro hardness instead of the expected decrease. The mechanism of the change in primary carbides was analyzed in detail in this paper, which has provided a new method for the refinement of primary carbides and for improving the properties of primary carbides.

Effect of Electric Current Pulse on Carbide in Hypereutectic High Chromium Cast Iron

2012 ◽  
Vol 457-458 ◽  
pp. 174-180 ◽  
Author(s):  
Hua Chen ◽  
Rong Feng Zhou ◽  
Ye Hua Jiang ◽  
Rong Zhou
Keyword(s):  
Cast Iron ◽  
Electric Current ◽  
Current Pulse ◽  
Processing Time ◽  
Hard Phase ◽  
Electric Current Pulse ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Primary Carbides ◽  
Chromium Cast Iron

It has significant engineering practicability that refining the carbides as hard phase in hypereutectic high chromium cast iron. The high chromium cast iron samples during the course of solidification were treated with electric current pulse (ECP) from the temperature of 1350 °C and 1360 °C. The effects of ECP treatment of starting temperature, processing time on the shape, size, and distribution of primary carbides was investigated. The mechanism of primary carbides refined by ECP process was also analyzed preliminarily.

The influence of retained austenite in high chromium cast iron on impact-abrasive wear

Wear ◽  
1990 ◽  
Vol 135 (2) ◽  
pp. 217-226 ◽  
Author(s):  
Tong Jian-Min ◽  
Zhou Yi-Zhong ◽  
Shen Tian-Yi ◽  
Deng Hai-Jin
Keyword(s):  
Cast Iron ◽  
Abrasive Wear ◽  
Retained Austenite ◽  
High Chromium ◽  
High Chromium Cast Iron ◽  
Chromium Cast Iron

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

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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