Texture and anisotropy of low-interstitial 18 Pct Cr-2 Pct Mo ferritic stainless steel
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developments in alloy steelmaking technology, particularly the argon-oxygen decarburization process, ~-3 have permitted the economical production of a new family of ferritic stainless steels. The alloys are characterized by chromium contents in the range of 17 to 30 pct, molybdenum contents in the range of 1 to 4 pct, and low interstitial contents, typically 0.015 pet carbon and 0.015 pct nitrogen. Because of their lower interstitial contents these steels are generally tougher, more weldable, and more formable than the previously produced ferritic stainless steels. One particular grade containing 18 pct Cr and 2 pct Mo has been shown to be competitive with Type 304 stainless steel in general corrosion resistance, and clearly superior to Type 304 in resistance to stress corrosion cracking. 4 Because of the relative economies in the production of the 18 pct Cr-2 pct Mo it is expected that it will be used in many applications, and that a large number of these applications will require the forming of sheet. As would be expected the stretchability of the ferritic 18 pct Cr-2 pct Mo stainless steel cannot compete with the excellent stretchability of the austenitic Type 304 stainless steel. However, using processing techniques developed for low-carbon steels, 5'6 it is possible to produce ferritic stainless steels with deep drawability greatly superior to that of the Type 304. In an earlier investigation 7 it was demonstrated that the deep drawability of the Ti-stabilized 18 pct Cr-2 pct Mo ferritic stainless steel increased rapidly with increasing cold reduction. This behavior, as well as the earing behavior during deep drawing, was explained in terms of the sheet textures resulting from cold rolling and annealing schedules used to produce the sheet. The present investigation was designed to extend the technology to include Nb-stabilized 18 pct Cr-2 pct Mo ferritic stainless steel and the effects of selected schedules of two cycles of cold rolling and annealing. R. M. DAVISON is Manager, Stainless Steel Development, Climax Molybdenum Company, a subsidiary of AMAX Inc., 3072 One Oliver Plaza, Pittsburgh, Pa. 15222. This manuscript is based on a talk presented at the symposium on Advances in Sheet Metal Forming, sponsored by the Mechanical Working and Forming Division, ASM, Chicago, lllinois, October 4, 1973. Manuscript submitted July 8, 1974. METALLURGICAL TRANSACTIONS A
EXPERIMENTAL
PROCEDURES
Three heats of 18 pct Cr-2 pct Mo ferritic stainless steel, two stabilized with niobium and one stabilized with titanium, were induction-melted in vacuum and cast under a partial pressure of argon. The compositions of the heats are given in Table I. The cast billets were hot-forged, hot-rolled, and cold-rolled to sheet. From each heat several sheets were produced, following different schedules of cold rolling and annealing, as listed in Table II. Plastic strain ratio measurements, Swift and Olsen cup tests, and stereographic pole figure analyses were performed for each of the experimental sheets following the same experi
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