Wear Mechanism of High Chromium White Cast Iron and Its Microstructural Evolutions During the Comminution Process
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ORIGINAL PAPER
Wear Mechanism of High Chromium White Cast Iron and Its Microstructural Evolutions During the Comminution Process Minal Shah1 · Kanai Lal Sahoo1 · Swapan Kumar Das1 · Goutam Das1 Received: 4 April 2020 / Accepted: 30 June 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The detailed deformation mechanism and its microstructural modifications of white cast iron grinding balls used in comminution have been investigated using transmission electron microscopy (TEM) and XRD. De-shaping is the primary mode of ball consumption, and fracture of balls is a relatively uncommon failure mode. Deshaping is the manifestation of abrasive wear caused during the operation, and abrasive wear is accompanied by microstructural changes. Micro-cutting is the foremost mechanism. The original microstructure of the matrix of unused grinding balls was observed to have twinned martensite ̄ }M//{113̄ }T and M-(12̄ 10)//ω(01̄ 10) and { 1̄ 13 ̄ }M// ̄ 1̄ ) and { 1̄ 13 with ω phase with an orientation relation of M-(12̄ 1)//T-(12 ̄ ̄ {12 1 3}ω. However, the presence of unstable ω phase, located at the twinning boundary, causes detwinning and forms lath martensite during tempering caused by localized heat during abrasion. Nano-cementite is formed at lath boundaries. Some cracking was observed, but the crack orientation is radial, indicating a response to tangential stresses associated with abrasion as opposed to dynamic stress waves from high-angle impact. Tangential tensile stresses due to surface traction during the abrasion process lead to radial cracks in brittle eutectic carbides, which join up and cause material removal. Graphical Abstract
Keywords Micro-cutting · Twinned martensite · Lath martensite · Detwinning
* Minal Shah [email protected] 1
Materials Engineering Division, CSIR-National Metallurgical Laboratory, Jamshedpur, Jharkhand 831007, India
1 Introduction The cement industry predominantly uses ball mills to grind raw materials. Among the dry grinding mills, the ball mill is most utilized for grinding clinker in the process of cement
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making. However, a few concerns such as ease of operation, cost, maintenance, and quality of products are still prevalent. The costs of grinding media and grinding efficiency comprise a significant share of the operational cost of cement production [1, 2]. If the grinding media become worn or deshaped, the output capacity decreases, leading to an increase in overall power consumption. As the cement manufacturing unit requires a substantial amount of energy, even a small improvement in its efficiency results in substantial power saving. Among the various steps in the cement manufacturing process, comminution consumes about 60% of the total energy. The comminution process reduces the size of raw material to a small feed ratio via a process of grinding and crushing and is a highly energy-intensive production step. It involves the operation of large ball mills to achieve a desired clinker partic
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