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2009
Conference Paper
Titel
Evaluation of thermal shock and mechanical wear on duplex treated hot working tool steel
Alternative
Beurteilung von Temperaturwechsel und mechanischem VerschleiĂź auf duplexbehandeltem Warmarbeitsstahl
Abstract
During operation, hot working tools are subjected to thermal, mechanical and tribological stress. This results in high abrasive and adhesive wear, which limits the tools' lifetime. The lifetime can be prolonged by appropriate surface treatments. This paper describes investigations on the combination of laser alloying or laser dispersing with a nitriding process. The target has been to increase the life time of hot working tools, more precisely of forging tools. Samples and selected forging tools were laser alloyed/dispersed in order to reduce the abrasive wear. The samples were subsequently nitrided to decrease the adhesive wear. The effect of this duplex treatment of surfaces was determined via the evaluation of each single process as well as their combination. Two special testing devices were developed to simulate the wear on hot working tools. A modified disc on disc test apparatus was especially suited to simulate thermal shock and mechanical wear of duplex treated hot working tool steels. By this, information on the properties and quality of the described duplex treatment was obtained within a few hours, instead of a long term testing period under real service conditions. Investigations using standard metallographic methods and micro hardness testing as well as microanalysis have been performed in addition.