Ductile-brittle transition behavior of rolled chromium

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 1273 K. 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 90degrees to the rolling direction. Some tensile specimens from the rolled sheets were annealed at 1473 K 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 500 K 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 400 K lower by 100 K than that of the as-sintered specimen. (C) 2004 Elsevier B.V. All rights reserved.