Columnar grain growth during annealing prior to cold rolling of non-oriented electrical steels

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 243; pp. 8 - 18
• Main Authors: Gutiérrez Castañeda, E.J., Palafox Cantú, C.N., Torres Castillo, A.A., Salinas Rodríguez, A., Deaquino Lara, R., Botello Rionda, F., Márquez Torres, F., García Guillermo, S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.04.2019; Elsevier BV
• Subjects: Annealing; Cold rolling; Columnar growth; Crystallographic texture; Crystallography; Cube texture; Decarburization; Decarburizing; Electrical steels; Grain growth; Grain structure; Heat treating; JMatPro simulation; Microstructure; Nucleation; Phase transformation; Phase transitions; Phase transformation; Electrical steels; JMatPro simulation; Crystallographic texture; Microstructure; Columnar growth
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2019.03.016

[Display omitted] •Intercritical annealing modifies grain structure and texture of hot-rolled bands.•Decarburization and isothermal γ-Fe → α-Fe transformation assist columnar grain growth.•Decarburization rate affects the driving force needed for columnar grain growth.•Bain and Kurdjumov-Sachs correspondence relationships may explain changes in texture.•Deformation texture is also modified: α and γ fibers weaken and θ-fibre strengthens. The present research reports the microstructural factors that favor the development of columnar grains during annealing prior to cold rolling (APCR). Results show that decarburization of steel has a strong effect on phase transformations, grain structure and crystallographic texture. Annealing at 850 °C (two-phase field) promotes the development of columnar-grained microstructures with orientations close to the ideal cube texture. Higher annealing temperatures within the intercritical region, results in a mixture of columnar + equiaxial grains (875 °C) or completely equiaxial-grained microstructures (900 °C). Annealing at temperatures within the single ferrite (700 °C, 750 °C) or austenite (950 °C, 1050 °C) phase fields does not promote the development of columnar grains. In these cases, annealing promotes the development of equiaxial grains with rotated cube texture and orientations along the γ-fibre. Changes in texture produced by APCR are consistent with the Bain and Kurdjumov-Sachs correspondence relationships and occur according to oriented nucleation and selective growth mechanisms depending on the characteristics of decarburization.