Non-isothermal analysis of die corner gap formation for materials deformed by multi-pass ECAP

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Medeiros, N.^1 ; Moreira, L.P.^1

Programa de Pós-graduação em Engenharia Metalúrgica, Universidade Federal Fluminense, 420 Av. dos Trabalhadores, CEP 27255-125 Volta Redonda RJ, Brazil^1

关键词: Effective plastic strain;    Final temperatures;    Friction conditions;    Isotropic plasticity;    Non-isothermal analysis;    Thermomechanical properties;    Upper bound models;    Upper bound solution;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012035/pdf
DOI  :  10.1088/1757-899X/63/1/012035

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

In this paper, the upper-bound solutions proposed by Eivani and Karimi Taheri [Comp. Mater. Sci. 42 (2008) 14] to calculate processing force and evaluate die corner angle Ψ formation in terms of tribology and die configurations during cold single pass equal channels angular pressed metals with constant flow stress were extended to work-hardening metals processed by two passes according to route A by using the Swift model combined to von Mises isotropic plasticity criterion. Also, adiabatic heat equation was coupled to solutions to express the final temperature of the workpiece. For that, thermomechanical properties of a hot-dip galvanized interstitial-free (IF) were considered and its behavior under pressing was evaluated to non-hardening and work-hardening conditions in all performed analyses. By including work-hardening in the models and for the critical friction factor of 0.4, theoretical predictions after single pass showed a decreasing of die corner angle and pressing force predictions and increasing of effective plastic strain and end temperature for all friction conditions and tooling geometries evaluated. In addition, after second pass, these responses showed higher values. Finally, with the proposed upper-bound models it was possible to analyze the dependency of angle Ψ, effective plastic strain, pressing load and sample temperature with the instantaneous workpiece height at the entry surface of deformation zone.