Although steels often exhibit excellent room temperature ductility, they can exhibit poor ductility at elevated temperatures. This may occur when the load is constantly increasing as in a tension test or when loading is static as in an elevated temperature creep test. The loss in ductility in creep is termed creep embrittlement. Creep embrittlement is defined as the loss in rupture ductility with increasing time to rupture to a minimum followed by a subsequent increase with increasing rupture time. This has been the subject of several excellent reviews (1 - 3) within the past ten years. A problem not as frequently studied is the problem in the loss of ductility at elevated temperatures under increasing load conditions. Elevated temperature tensile embrittlement is critical in high temperature forming of steels. Most failures during hot forming can be attributed to localized tensile loading and a lack of sufficient ductility at the forming temperature. The improper selection of forming temperature and amount of deformation without reheating can result in failures that could have otherwise been avoided.
