Effect of Texture on r-value of Ferritic Stainless Steel Sheets

Abstract

The effects of cold rolling texture on the formation of recrystallization texture and the relationship between recrystallization texture and r-value were investigated for sheets of titanium-stabilized extra-high purity Type 436L and Type 409L ferritic stainless steels. The recrystallization texture and average r-value were affected by the cold rolling texture. Annealed sheets with a sharp γ-fiber texture and very high average r-values were obtained from cold-rolled sheets with a strong γ-fiber texture (Type A). On the other hand, the {h,1,1}<1/h,1,2> fiber texture developed from cold-rolled sheets with a strong α-fiber texture (Type C). In terms of the relationship between {111} intensity and the average r-value, chromium content had less effect than the cold rolling texture. The planar anisotropies of r-values and the average r-values of Type 436L and 409L sheets with Type A cold rolling textures agreed well with those calculated from the textures in the center layers by using the relaxed-constraints model and the CRSS ratio τc{211}/τc{110} of 1.1. On the other hand, for the sheets with Type C cold rolling textures and a marked texture gradient, it was necessary to consider the texture gradient in the thickness direction. The texture inhomogeneity by the orientations other than {111} texture affected the relationship between {111} intensity and average rvalue.

Texture and Planar Anisotropy in Lean Duplex Stainless Steel Sheet

“…[23][24][25][26][27][28] In a previous paper, 16) the authors illustrated that the texture of the α phase in Type 329J4L was dominant for the anisotropy of r-value. Furthermore, like a case of single-phase ferritic steels, 20,29) the r-values in Type 329J4L calculated from the texture of the α phase using the relaxed-constraints (RC) model with the RC1323 and a critical resolved shear stress (CRSS) ratio of 1.1 were in good agreement with the experimental values. 16) Here, the RC1323 model, i.e., the pancake version in which e13 and e23 (where 1, 2, and 3 are defined as the tensile, width, and thickness directions, respectively) were left free, and the CRSS ratio was the same as that for the {211} and {110} glide planes (τ c{211} /τ c{110} ).…”

“…1 and 6. Generally, high temperature annealing often improves the r-value in ferittic stainless steel sheets, 19,20) but the r-value in the DSS is different from that in a single α phase. The fraction of α phase increases with high temperature annealing in the case of DSS.…”

Evaluation of Intermediate Annealing on Nb-Stabilized Ferritic Stainless Steel

“…Moreover, some authors 17,28 have reported that θ-fiber is unfavorable when attempting to obtain a high r ̅ value. Hamada et al 12 demonstrated that the r ̅ value for the {100}〈011〉 and {100}〈001〉 orientations are notably low in almost all directions. The reduction of the θ-fiber fraction, from the 0.11 to 0.08, obtained with the addition of intermediate annealing improves the r ̅ value, and the γ/θ ratio reached approximately 5.25.…”

“…Yazawa et al 11 reported that the r ̅ value is related to the γ-fiber in the recrystallization texture. Furthermore, the enhancement and uniformity of the γ-fiber is essential in order to improve the r ̅ value [10][11][12] .…”

“…Huh and Engler 7 cited that an improvement in formability can be obtained by controlling the crystallographic texture. Control methods for the improvement of the γ-fiber recrystallization texture have been attempted by some approaches, such as refinement of the hot rolled microstructure, annealing of the hot rolled bands, optimization of cold rolling, intermediate annealing in cold rolling, and reduction of carbon in a solid solution [10][11][12] .…”