Wear resistant coatings of boron-modified stainless steels deposited by Plasma Transferred Arc

摘要

In this research work the microstructure and wear resistance of boron-modified stainless steel coatings were investigated. The coatings were produced by Plasma Transferred Arc (PTA) with powders of supermartensitic and superduplex stainless steel with 1 and 3 wt.%B addition, respectively. The deposition was carried out on AISI 4140 steel substrate. Microstructural characterization revealed dendritic growth in both cases; however, the amount of borides formed was quite different, around 14% for supermartensitic with 1 wt.%B and 32% for superduplex with 3 wt.%B. Thermodynamic calculations were used to predict phase formation and solidification paths resulting in good agreement with the experimental results. The wear resistance was characterized by dry sand/rubber wheel and reciprocating pin-on-plate tests. In dry sand/rubber wheel the volume loss of quenched and tempered AISI 4140 was superior to supermartensitic steel with 1 wt.%B, nonetheless it was comparable to superduplex steel with 3 wt%B. On the other hand, regarding the pin-on-plate tests, the wear resistance of both boron-modified steels was far superior. The formation of hard borides increased both the hardness and overall wear resistance of boron-modified stainless steels. Additionally, the high boride fraction was responsible for the superior wear performance of superduplex with 3 wt.%B. (C) 2016 Elsevier B.V. All rights reserved.