Large-Area Wear-Resistant Pattern Hardfacing of Scraper Conveyor Middle Trough

Literature Overview

This paper by Zheng Yanting, Ge Changlu, Liu Yugao, and Li Yong, published in Coal Science and Technology (1995, Vol. 23, No. 2, pp. 26-27), describes the application of large-area wear-resistant pattern hardfacing on the middle trough of scraper conveyors. The collaboration between China University of Mining and Technology and Yungang Mine began in 1992, using KD-1 and KD-2 (EDCrWB type) wear-resistant hardfacing electrodes developed by the university. The hardfacing was applied to both new and used SGB-764/... scraper conveyor middle troughs to improve their wear resistance.

Core Technical Content

Scraper conveyors are essential equipment in underground coal mining, transporting mined coal from the face to the main haulage system. The middle trough of the conveyor is a critical component that experiences severe abrasive wear from the coal and rock material being transported. The wear-resistant hardfacing technology described in this paper extends the service life of these troughs significantly, reducing replacement frequency and maintenance costs.

Hardfacing Materials and Pattern Design

The KD-1 and KD-2 hardfacing electrodes are chromium-based alloy consumables (EDCrWB type) that produce hardfacing deposits with high hardness and excellent abrasive wear resistance. The pattern hardfacing approach involves applying hardfacing in a specific geometric pattern rather than covering the entire trough surface. This approach optimizes material usage while providing wear protection in the most critical areas.

The pattern design of the hardfacing is critical for balancing wear protection with material economy. The hardfacing is applied in areas where the trough surface contacts the scraper chain and coal material, while areas not subject to significant wear are left unhardfaced. This approach reduces the consumption of expensive alloy consumables while maintaining effective wear protection.

Process Development and Application

The collaborative research between the university and the mine followed a systematic approach: material development, laboratory testing, pilot-scale trials, and full-scale application. The hardfacing process parameters were optimized through trial welding and service testing to ensure adequate bond strength, hardness, and wear resistance. The ability to apply hardfacing to both new and used troughs is a significant advantage, as it extends the service life of existing equipment and reduces the need for complete replacement.

Quality control of the hardfacing operation involves checking for defects such as porosity, cracking, spalling, and insufficient penetration. The hardness of the hardfacing deposit is verified through surface hardness testing, and the bond strength between the hardfacing layer and the base metal is assessed through pull-off testing or service performance evaluation.

Study Insights and Implications

This paper demonstrates the practical application of wear-resistant hardfacing technology in a demanding industrial environment. The collaboration between academic researchers and industrial practitioners is a model for technology transfer and practical implementation. The pattern hardfacing approach is particularly noteworthy for its economic efficiency, as it applies expensive alloy material only where needed. For engineers working on similar wear protection applications, the key lessons include the importance of systematic material and process development, the value of academic-industry collaboration, and the economic benefits of targeted rather than full-surface hardfacing. The methodology described here is directly transferable to other wear-prone components in mining and materials handling equipment.