Contents lists available at ScienceDirect Materials Characterization journal homepage: www.elsevier.com/locate/matchar Evolution of texture in precision seamless tubes investigated by synchrotron and neutron radiation measurement F. Foadian a,b , A. Carradó b , H.G. Brokmeier c,d , W.M. Gan e , N. Schell f , N. Al-Hamdany c , H. Palkowski a, ⁎ a Institute of Metallurgy, Clausthal University of Technology, 38678 Clausthal-Zellerfeld, Germany b Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS-UMR - 7504, 23, rue du Loess BP 43, 67034 Strasbourg, France c Institute of Materials Engineering, Clausthal University of Technology, Agricolastrasse 6, 38678 Clausthal-Zellerfeld, Germany d Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, Geb. 33, 21502 Geesthacht, Germany e German Engineering Materials Science Center at MLZ, Helmholtz-Zentrum Geesthacht, D-85748 Garching, Germany f German Engineering Materials Science Center, Helmholtz-Zentrum Geesthacht, D-20095 Hamburg, Germany ARTICLE INFO Keywords: Texture evolution Tube drawing Tilting Copper tube Pole figure Orientation distribution function (ODF) ABSTRACT High precision dimensionality tubes are required for a number of applications. Nevertheless, there are some troubles and challenges to produce high quality tubes in a cost-effective way. In recent works done at the Institute of Metallurgy at Clausthal University of Technology, the tube drawing process was optimized by in- troducing dynamic tilting and shifting of the die. These methods made it possible to control the wall-thickness variation and even residual stresses (RSs) evolution. A possible influence on texture evolution, however, has not yet been investigated, though it is well known that the crystallographic texture has a remarkable effect on materials' properties. Furthermore, the initial texture clearly influences the microstructural evolution during plastic deformation, affecting the RSs evolution and dimension accuracy, too. In this paper the evolution and heterogeneity of the texture are introduced for tube drawing performed with a tilted die. The measurements were done using synchrotron and neutron diffraction methods. The aim was to understand the behavior of the material during the asymmetrical tube drawing, caused by the tilted die, and connect the effects between ec- centricity and residual stresses. Pole figures and ODF densities were studied and the creation and variation of different texture components were analyzed as well. 1. Introduction 1.1. Tube Drawing with Tilted Die To get the desired wall thickness and diameter for the final product, pre-tubes are drawn using a tube drawing process. The advantages of this method compared to other metal-forming processes are the possi- bility to produce tubes of smaller diameters and wall thicknesses, small dimensional tolerances, and adapted mechanical properties, gaining a better surface finish with almost no limitation of the tubes lengths [1]. This process is characterized by a quasi-stationary mass flow. There- fore, the velocity field - which the material particles define - remains more or less unchanged throughout the process [2]. In an ideal drawing process, the initial flow of material happens in the die cavity filled with the material and then, the material starts to flow homogeneously into the cylindrical part of the die and almost a one-directional flow in the direction of the drawing forms [3]. Wang et al. studied the deformation velocity field using the power equilibrium method and investigated the mass flow for a die-less drawing process theoretically and experimen- tally [4]. However, in most industrial tube productions - due to reasons such as vibrations of the mandrel [5], tolerances in positioning of the die and the billet, as well as local temperature differences within the billet - this ideal mass flow is disturbed and, as a consequence, variations in thickness can occur along the tube's length and around its cir- cumference. The latter one is called eccentricity, E [6]. As shown in Fig. 1, it is defined as the percentage of the maximum variation in tube wall thickness from an average value within the same tube's cross section, as described by Eq. (1) [7]. = − + E t t t t max min max min (1) https://doi.org/10.1016/j.matchar.2019.03.041 Received 31 January 2019; Received in revised form 18 March 2019; Accepted 26 March 2019 ⁎ Corresponding author. E-mail address: heinz.palkowski@tu-clausthal.de (H. Palkowski). Materials Characterization 151 (2019) 582–589 Available online 29 March 2019 1044-5803/ © 2019 Elsevier Inc. All rights reserved. T