Development of Ni{sub 3}Al alloys for use as transfer rolls in hot processing of steels. CRADA final report

Abstract

The purpose of this cooperative effort was to evaluate the potential of Ni{sub 3}Al alloys, such as IC221M and IC396M, for use as transfer rolls in heating treating furnaces and slab reheating furnaces used during the normal hot processing of steel ingots into rolled products. Rolls consist of three parts: the center tube section which forms the roll surface in direct contact with the steel, and the sections welded at each end of the tube, called trunnions, which bear the load. The work in this CRADA focused on weldments and base materials. The transfer rolls in the furnaces used in the hot processing of steel have been made, almost exclusively, from iron-chromium-nickel heat resistant alloys for over 35 years. The iron-based heat resistant alloys experience a variety of problems when exposed to temperatures above 760 C including: cracking, dimensional instability, and excessive oxidation. Many defects in rolled steel products can be traced directly to rolls used in the processing. Also the demand for higher quality products, spurred in part by competition from foreign producers, requires that various avenues for improving overall quality of rolled steel products be pursued. Initial work done by the Contractor and Metallamics indicated that Ni{sub 3}Al alloys may perform better than existing iron-chromium-nickel alloys do as transfer rolls in heat treating furnaces. The use of Ni{sub 3}Al may lead to rolls with longer operational life, improved high temperature oxidation resistance and mechanical properties, higher quality rolled steel products, and improved energy and operational efficiencies in the hot processing of steel. The goal of the work was to test Ni{sub 3}Al alloys for the transfer roll application in order to improve process efficiency, minimize waste by virtue of producing rolled steel of higher quality and to enhance the competitiveness of US-based steel producers.