METHODS FOR IMPROVING THE MECHANICAL AND OPERATIONAL PROPERTIES AND WEAR RESISTANCE OF HIGH-CHROMIUM WHITE CAST IRONS

Abstract

<p>This&nbsp;study&nbsp;presents&nbsp;the&nbsp;results&nbsp;of&nbsp;extensive&nbsp;research&nbsp;aimed&nbsp;at&nbsp;improving&nbsp;the&nbsp;mechanical,&nbsp;tribological,&nbsp;and&nbsp;performance&nbsp;properties&nbsp;of&nbsp;high-chromium&nbsp;white&nbsp;cast&nbsp;irons&nbsp;used&nbsp;to&nbsp;manufacture&nbsp;wear-resistant&nbsp;components&nbsp;for&nbsp;mining&nbsp;and&nbsp;mineral-processing&nbsp;equipment.&nbsp;The&nbsp;relevance&nbsp;of&nbsp;the&nbsp;study&nbsp;stems&nbsp;from&nbsp;the&nbsp;need&nbsp;to&nbsp;increase&nbsp;the&nbsp;service&nbsp;life&nbsp;of&nbsp;cast&nbsp;components&nbsp;operating&nbsp;under&nbsp;conditions&nbsp;of&nbsp;intense&nbsp;abrasive&nbsp;wear,&nbsp;impact&nbsp;loads,&nbsp;and&nbsp;corrosive&nbsp;environments,&nbsp;while&nbsp;simultaneously&nbsp;reducing&nbsp;the&nbsp;</p><p>consumption&nbsp;of&nbsp;expensive&nbsp;alloying&nbsp;elements.&nbsp;The&nbsp;study&nbsp;focused&nbsp;on&nbsp;high-chromium&nbsp;white&nbsp;cast&nbsp;iron&nbsp;grades&nbsp;280Х29НЛ,&nbsp;300Х32Н2М2ТЛ,&nbsp;and&nbsp;330Х17Л,&nbsp;which&nbsp;are&nbsp;widely&nbsp;used&nbsp;in&nbsp;the&nbsp;production&nbsp;of&nbsp;components&nbsp;for&nbsp;crushing&nbsp;and&nbsp;grinding&nbsp;equipment.&nbsp;The&nbsp;influence&nbsp;of&nbsp;chemical&nbsp;composition,&nbsp;crystallization&nbsp;conditions,&nbsp;cooling&nbsp;rate,&nbsp;and&nbsp;casting&nbsp;technology&nbsp;on&nbsp;microstructure&nbsp;&nbsp;systematically&nbsp;studied.&nbsp;To&nbsp;evaluate&nbsp;phase&nbsp;transformations&nbsp;and&nbsp;carbide&nbsp;formation&nbsp;during&nbsp;quenching,&nbsp;thermodynamic&nbsp;phase&nbsp;analysis&nbsp;was&nbsp;performed&nbsp;using&nbsp;Thermo-Calc&nbsp;software&nbsp;and&nbsp;the&nbsp;TCFE13&nbsp;database.&nbsp;Increasing&nbsp;the&nbsp;cooling&nbsp;rate&nbsp;during&nbsp;cold&nbsp;casting&nbsp;promotes&nbsp;refinement&nbsp;of&nbsp;carbide&nbsp;phases,&nbsp;improves&nbsp;the&nbsp;distribution&nbsp;of&nbsp;M7C3&nbsp;and&nbsp;M23C6&nbsp;carbides,&nbsp;and&nbsp;strengthens&nbsp;the&nbsp;metallurgical&nbsp;bond&nbsp;between&nbsp;carbide&nbsp;particles&nbsp;and&nbsp;the&nbsp;metal&nbsp;matrix.&nbsp;As&nbsp;a&nbsp;result,&nbsp;the&nbsp;hardness,&nbsp;wear&nbsp;resistance,&nbsp;and&nbsp;overall&nbsp;impact&nbsp;toughness&nbsp;of&nbsp;the&nbsp;castings&nbsp;are&nbsp;significantly&nbsp;increased&nbsp;without&nbsp;additional&nbsp;alloying.&nbsp;Castings&nbsp;produced&nbsp;in&nbsp;metal&nbsp;molds&nbsp;had&nbsp;a&nbsp;hardness&nbsp;of&nbsp;58–62&nbsp;HRC,&nbsp;while&nbsp;their&nbsp;wear&nbsp;resistance&nbsp;was&nbsp;improved&nbsp;by&nbsp;20–30%&nbsp;compared&nbsp;with&nbsp;castings&nbsp;produced&nbsp;in&nbsp;conventional&nbsp;sand&nbsp;molds.&nbsp;Industrial&nbsp;tests&nbsp;conducted&nbsp;on&nbsp;CEMCO&nbsp;KEV&nbsp;96&nbsp;crushers&nbsp;confirmed&nbsp;that&nbsp;the&nbsp;proposed&nbsp;technology&nbsp;increases&nbsp;the&nbsp;service&nbsp;life&nbsp;of&nbsp;critical&nbsp;wear&nbsp;components&nbsp;by&nbsp;at&nbsp;least&nbsp;1.2&nbsp;times.&nbsp;The&nbsp;obtained&nbsp;results&nbsp;show&nbsp;that&nbsp;optimization&nbsp;of&nbsp;quenching&nbsp;parameters,&nbsp;casting&nbsp;technology,&nbsp;and&nbsp;microstructure&nbsp;evolution&nbsp;is&nbsp;an&nbsp;effective&nbsp;approach&nbsp;to&nbsp;improving&nbsp;the&nbsp;performance&nbsp;of&nbsp;high-chromium&nbsp;white&nbsp;</p><p>cast&nbsp;irons,&nbsp;reducing&nbsp;production&nbsp;costs,&nbsp;and&nbsp;decreasing&nbsp;the&nbsp;consumption&nbsp;of&nbsp;alloying&nbsp;</p><p>elements&nbsp;in&nbsp;the&nbsp;mining&nbsp;industry.</p>