Effect of cooling conditions on microstructure evolution and wear behavior of high chromium cast iron hardfacing layer

Abstract

The influences of cooling conditions on the microstructure and abrasive wear behavior of arc surfacing layer of high chromium cast iron (HCCI) were investigated. The surfacing alloys were prepared by air and liquid nitrogen cooling. Microstructure of the alloys was studied by optical microscopy and scanning electronic microscopy, and the wear behavior was researched using pin-on-disk test. The primary austenite (P-A) was refined and its morphology was improved significantly by liquid nitrogen jet cooling. The wear resistance test indicated that under the same conditions, the liquid nitrogen jet cooling hardfacing alloy showed better wear resistance. According to analyzing the worn surfaces, the size of P-A and abrasive particles, the wear mechanism was revealed. Specifically, as the weak structure of surfacing alloy, P-A was easily penetrated by SiC particles. When the abrasive particles own the penetrable size as well as the cutting ability to P-A, the wear of surfacing alloy is intensified.