Failure analysis and flexural behavior of high chromium white cast iron and AISI4140 Steel bimetal beams

Failure analysis and flexural behavior of high-Cr white cast iron (HCWCI) and AISI4140 Steel bimetal beams in the as-cast condition under 3PB test were experimentally and numerically investigated. The bimetal beams of HCWCI as a wear resistant part and AISI4140 Steel as a ductile part were fabricated using a new method. In this method, the two parts of bimetal castings are joined mechanically together by dovetail joint and/or connector pins. The experimental results showed that the flexural strengths of the bimetal beams were excellent and ranged from 650 to 790 MPa. The bimetal beam with sufficient connector pins exhibited the highest flexural strength compared with the other bimetal casting specimens. The numerical results of the bimetal beams are in agreement with the experimental results. The failure of the bimetal beams occurred in three stages. In the first stage, a sliding crack (mode II) initiated at the interface between the wear resistant and ductile parts at the mid-span of specimens. In the second stage, mode I crack initiated in the wear resistant part at the mid span and propagated toward the point of loading. In the last stage, a third main crack initiated and propagated in the ductile part.