Because coal mine machinery operates underground, the production environment is harsh, equipment failures are frequent, and maintenance space is limited. Many parts cannot be replaced or repaired underground, significantly increasing the difficulty of maintenance and impacting smooth coal mine production. The widely used intermediate troughs are a typical example. Therefore, adopting plasma cladding remanufacturing technology in the coal mining industry to improve the surface performance of vulnerable parts and extend their service life is of particular significance.
Scraper Conveyor Intermediate Trough
Intermediate troughs are mainly used in underground scraper conveyors and transfer conveyors in coal mines. During use, these troughs are subjected to abrasion from scrapers and chains, as well as abrasive wear from coal particles. Without wear-resistant treatment, the surface is easily worn into pits and fails. The large number of intermediate troughs used and the high maintenance volume present a significant problem to be solved. Remanufacturing during maintenance will generate significant economic benefits.
Powder plasma cladding technology is the best process for repairing scraper conveyor intermediate troughs.
Powder plasma cladding is a surface cladding alloy technology that uses an argon plasma arc as a high-temperature heat source and alloy powder as filler metal. It is one of the new surface hardening methods and has the following characteristics:
(1) High productivity.
(2) Good weld layer quality and process stability.
(3) The cladding process is pollution-free, automated, and achieves mechanized and automated operation, reducing labor intensity.
The non-arc phase acts as a transition ignition and arc conversion, and can also be used as an auxiliary heat source. The anode of the non-arc phase is on the nozzle orifice wall; most of the heat from the arc is transferred to the nozzle and carried away by cooling water, which is detrimental to nozzle cooling and negatively impacts the stability of the cladding process. Therefore, even if it is retained during the cladding process, the current specification should not be too high, generally below 50A. The non-arc current should be adjusted accordingly based on the specifications of the cladding workpiece; this data is not fixed.