Powder Processing of TRIP Steel.

摘要

Prealloyed powder of a TRIP steel alloy was prepared by the rotating electrode process. The powder was consolidated to bar stock by extrusion at 1800or 2000 F. The bar stock was rolled at 850 F to a series of reductions up to 80% with and without intermediate solutionizing. Rolled strips were evaluated in tension tests,which showed the capability of suitably processed powder to achieve the combination of high strength and ductility demonstrated in cast/wrought stock. Stock prepared by extrusion of powder at 2000 F was outstanding in strength,elongation,and reduction of area when warm rolled at 850 F directly from extrusion without intermediate solutionizing. The mechanical behavior of powder subjected to the various combinations of extrusion and solutionizing can be understood with the help of the metallographic observations. The 1800 F extrusion contains substantial precipitates,presumably carbides,which are detrimental to mechanical behavior. Solutionizing removes these carbides,providing material similar to cast/wrought stock as prepared for the warm rolling. The 2000 F extrusion has solutionized structure,not amenable to improvement by a subsequent solutionizing anneal. (Author)