Ductile–brittle transition behavior of rolled chromium

Abstract

The ductile–brittle transition behavior of the rolled chromium was examined by means of the tensile test. The workpieces taken from the as-sintered block were repeatedly rolled with or without the intermediate annealing. The rolling was performed with a reduction of 10% in every pass up to 50 or 85% in total reduction with or without the intermediate annealing at 1273K. Tensile specimens taken from the as-sintered block and the rolled sheets were tested in tension. Tensile axes for the specimens prepared from the sheets were at 0, 45 and 90° to the rolling direction. Some tensile specimens from the rolled sheets were annealed at 1473K in vacuum to examine the effect of grain coarsening on the transition temperature. DBTT of the specimens prepared from the rolled sheets without the intermediate annealing was considerably higher than the temperature 500K which was found in the as-sintered specimen. However, DBTT of the rolled specimens with the intermediate annealing was independent of rolling reduction and the tensile axis. It was found that DBTT of the rolled specimens with the intermediate annealing occurred at 400K lower by 100K than that of the as-sintered specimen.