Papers by Keyword: R-Value

Abstract: Using the cold rolled High Strength IF Steel sheet of 1.0 mm thickness as the test material,the r value and recrystallization texture were investigated by the tensile test and X Radial Diffraction Device.The results show that the test steel were annealed by heating to 760°C,800°C,840°C and holding sixty seconds,and with the increase of the annealing temperature ,the recrystallization finished and the texture to obtain the full evolution,and the r value of the steel grown.After the annealing,the recrystallization texture shows strong γ-fiber texture,homogeneous γ-fiber and weak α-fiber texture,and the texture strength change rule with the annealing temperature change was gained.

Abstract: Control of single crystal orientation in modern gas turbine components is a critical quality control issue for optimum reliable behaviour, and an increasingly important aspect of trade. This paper reviews industrial practice for the determination of primary crystal orientation and for the determination of 'disorientation' (R-value) between sub-grains. Different techniques and measurement conventions are compared, and the errors of measurement have been assessed through a European round-robin. Causes of poor reproducibility in 'disorientation' measurement have been identified by EBSD investigations. Recommendations for unified practice have been made in a Good Practice Guide as a precursor to a new industry-wide standard.

Abstract: The microstructure, texture and basic stamping properties of AZ31 magnesium sheet are studied in this paper with optical microscopy (OM), scan electron microscopy (SEM), X-ray diffraction (XRD) and MTS universal tester. The results show that the basal texture (0002) is enhanced and the grain size decreases as the thickness of sheet decreases. However the texture depresses in the 0.52mm sheet due to the complete recrystallization under deep rolling reduction. The strength and elongation decreases and the strain hardening index (n value) increases as the thickness increases. The precipitation decreases and the basal texture depresses after annealing treatment. The peak value ratio of crystal plane (0002) of 1.3mm sheet reduces from 67% to 53% when annealing treated at 300°C for 2h. In addition, the strain hardening index (n) value reduces from 0.2535 to 0.2053 and the anisotropic index (r) value increases from 1.966 to 2.108 when the sheet is treated at the same condition.

Abstract: This paper shows that different materials have different quadratic functions, tensor function theory can make the function of history to represent the plastic strain, which can be a sheet metal pressing does uniaxial tensile test show that the plane of sheet metal, sheet metal specimen axis and the angle between the rolling direction changes, to the metal plastic strain ratio (R) along with the changes. To explain this phenomenon, the introduction of a quadratic yield function to describe the experimental results of some of the metal sheet. This paper shows that different materials have different quadratic functions, tensor function theory can make the function of history to represent the plastic strain, which can be a sheet metal pressing does not depend on the value of history.

Abstract: Through the rolling and performance test, effect of cold-rolled micro-carbon steel rolling parameters and annealing temperature has been obtained on deep-drawing properties. Rolling texture was detected by X-ray diffraction and analyzed by a quantitative of ODF. R-plastic strain ratio was consistent with texture analysis, which provided with a basis for formulating the process parameters of cold-rolled and annealing of micro-carbon steel.

Abstract: Rub of roll and strip has effect on the texture form of surface strip, in IF steel rolling. The <110>//ND density decreased in surface strip in good lubrication condition rolling, the rolling texture become evenly in thickness direction, {111} texture is dominant, so that r-value increased. Otherwise, the {111} texture become unevenly and r-value decreased. It is must better lubricated for r-value rise, the conclusion is verified by the rolling text and texture analysis.

Abstract: Aluminum alloy sheets have lower formability (r-value) than low carbon steel sheets in fully annealed condition. Because the texture of fully annealed aluminum alloy sheet is mainly consists of cube component {001}<100>, which shows low formability. Asymmetric rolling, one of the severe plastic deformations, gives rise to shear deformation texture through the Al sheet thickness. In this paper, the changes of texture components after the severe deformation and subsequent heat treatment in Al sheet were observed. The change of the formability after the severe plastic deformation and subsequent heat-treated Al sheets have been analyzed with the change of texture of Al alloy sheets.

Abstract: High-strength IF steel sheet has increasingly attracted more attention of steelmakers in recent years as it has the potential to lighten the weight of automobiles and save energy and lower the production cost. In this paper, the effect of processing parameters on microstructures and mechanical properties especially deep drawability of ferritic-rolled P-added high strength Ti-stabilized IF steels were investigated and the precipitates in the steels were also analyzed. The results show that lubricant condition has great influence on the r-value and deep drawability of high-strength IF steels. And with the decrease of rolling temperature in ferrite region, the deep drawability of steels is improved.

Abstract: The influence of the texture on ridging and forming properties of transformable 16mass-%Cr steel was studied for two different specific processing routes. In the first route (HACA), hot strips were annealed prior to cold rolling, whereas in the second route (HCA), un-annealed hot strips were directly subjected to cold rolling. Results indicate that compared to HACA, HCA results in an improved surface smoothness, i.e. reduced roping, but a lower mean r-value, as a result of strengthening of the α-fiber texture components. Differences in the roping and forming properties could also be achieved by compositional differences resulting in differences in the fraction of austenite at hot rolling temperatures.

Abstract: Ti stabilized AISI 439 type 18% Cr ferritic stainless steel offers an attractive alternative for replacing Ni-containing austenitic steels. The influence of the cold rolling reduction on texture development and the planar anisotropy of Ti-stabilized 18% Cr ferritic stainless steel have been studied in order to find an optimized processing route to obtain improved formability properties. In the present study, both annealed and un-annealed hot strips were given different cold rolling reductions up to 86%, and recrystallization annealed. The recrystallization texture was analyzed by means of XRD. Tensile tests were carried out on cold rolled and annealed samples oriented in seven different directions to the rolling direction to evaluate the planar anisotropy in detail. The mean normal anisotropy rm increased with increasing cold reduction for both annealed hot band and un-annealed hot band. The planar anisotropy revealed a behavior related to the development of the recrystallization texture component in the annealed hot band and the texture component in the un-annealed hot band, with increasing cold reduction.