Effects of Punch Cross-Section on Deep-Drawability of Square Shell of Aluminum Sheet

1987 ◽  
Vol 109 (4) ◽  
pp. 355-361 ◽  
Author(s):  
N. Kawai ◽  
T. Mori ◽  
H. Hayashi ◽  
F. Kondoh
Keyword(s):  
Crack Initiation ◽  
Cross Section ◽  
Pure Aluminum ◽  
Metal Flow ◽  
Aluminum Sheet ◽  
Forming Limit ◽  
Planar Anisotropy ◽  
Deep Drawability ◽  
Commercially Pure ◽  
Relief Effect

Effects of product shape and a planar-anisotropy on a square shell drawability were studied, using commercially pure aluminum sheet. Two phenomena were mainly considered to affect a forming limit: (a) the prevention of crack initiation at the corner of a punch by adjacent straight punch profile regions, (b) the metal flow in the flange region from the corner to the straight side, the “Strain Relief Effect,” which serves to decrease the deformation at the corner.

Boss Forming, An Environment-Friendly Rotary Forming

2007 ◽  
Vol 344 ◽  
pp. 947-953 ◽  
Author(s):  
K. Kawai ◽  
H. Koyama ◽  
T. Kamei ◽  
W. Kim
Keyword(s):  
Experimental Study ◽  
Circular Plate ◽  
Working Conditions ◽  
Room Temperature ◽  
Pure Aluminum ◽  
Metal Flow ◽  
Forming Process ◽  
Environment Friendly ◽  
Commercially Pure ◽  
Technological Possibility

Boss forming, which is sometimes called hub forming, has attracted its attention as an environment-friendly rotary forming process to form a circular plate with a hole into a boss shape. An experimental study was conducted to survey the technological possibility of boss forming. Boss forming of A1050-O commercially pure aluminum plate of 10 mm thickness was carried out at room temperature under various working conditions. The effects of the working conditions on the metal flow in boss forming were clarified experimentally.

Pulsewise-Motion Controlled Stamping for Microtexturing Onto Aluminum Sheet

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Tatsuhiko Aizawa ◽  
Tatsuya Fukuda
Keyword(s):  
Pure Aluminum ◽  
Metal Flow ◽  
Numerical Control ◽  
Aluminum Sheet ◽  
Normal Loading ◽  
Precise Control ◽  
Dlc Coating ◽  
Diamondlike Carbon ◽  
Oxygen Plasma Etching ◽  
Loading And Unloading

High density oxygen plasma-etching was applied to microtexturing onto the diamondlike carbon (DLC) films coated on the die-unit substrates. This mold-die unit with microtextured DLC coating was fixed into a cassette die for computer numerical control (CNC) stamping with the use of precise control both in loading and feeding the sheet materials. In particular, the pulsewise-motion control in stamping was employed to describe the effect of loading and unloading subsequences in the incremental motion on the microtexturing with reference to the normal loading motion. The macroscopic plastic deformation as well as the microscopic metal flow were studied to prove that the pulsewise-motion should be responsible for homogeneous duplication of microcavity patterns into a pure aluminum sheet with high aspect ratio.

A Consideration on Deep-Drawability of Commercially Pure Aluminum Sheets

1985 ◽  
Vol 107 (4) ◽  
pp. 379-386
Author(s):  
N. Kawai ◽  
T. Mori ◽  
N. Hayashi ◽  
A. Eguchi ◽  
Y. Yasui
Keyword(s):  
Fracture Strength ◽  
Strain Path ◽  
Pure Aluminum ◽  
Drawing Ratio ◽  
Weak Correlation ◽  
Deep Drawability ◽  
Aluminum Sheets ◽  
Commercially Pure ◽  
Future Problem ◽  
R Value

Correlation between the deep-drawability of commercially pure aluminum sheets and the r value is investigated in detail. First, sheets with various r values are specially made for this study, and the conditions for making extra high r-value sheets are clarified. Then, it is found from the deep-drawability test that the limiting drawing ratio has a positive though weak correlation with r value. The reasons are considered both from the standpoints of drawing resistance and fracture strength and attributed to the variations of the r value during working. As a result, finding a strain path to enhance the r value is considered to be a future problem in the improvement of deep-drawability.

Evolution of Recrystallization Textures in Cold-Rolled Commercially Pure Aluminum

2016 ◽  
Vol 879 ◽  
pp. 2365-2370
Author(s):  
Dong Nyung Lee
Keyword(s):  
Volume Fraction ◽  
Pure Aluminum ◽  
Cube Texture ◽  
Rolling Texture ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Aluminum Sheet ◽  
Goss Texture ◽  
Commercially Pure ◽  
Cold Rolled

The evolution of recrystallization texture in commercially pure aluminum sheet cold-rolled by 90% reduction in thickness was measured by Juul Jensen et al. The cold-rolling texture consisted of the Goss {110}<001>, Brass {110}<112>, S {123}<634>, and copper {112}<111> components. When the cold-rolled aluminum sheet was annealed at temperatures between 253 and 341°C for times between 5 min and 20 h., the cube {001}<100> component evolved. The evolution of the cube texture cannot be explained by either the oriented nucleation theory by Burgers and Louwerse or the oriented growth theory by Barrett. The cube texture evolution originates from the Copper component by the strain-energy-release-maximization (SERM) theory by Lee. Once the Cube oriented, dislocation free nuclei evolve, they are in the best position to grow at the expense of neighboring deformed high energy grains of the Goss, Brass, S, and Copper orientations, and the volume fractions of the Goss, Brass, S, and copper components would decrease. However, the volume fraction of the Goss component increased a little at annealing temperatures of 253 and 278°C, at variance with expectation. Low stacking-fault-energy alloys with the brass {110}<112> rolling texture evolve the {236}<385> texture after recrystallization, whereas high stacking-fault-energy alloys with the brass rolling texture evolve the Goss texture after recrystallization by the SERM theory, resulting in the increase of the volume fraction of the Goss texture.

scholarly journals Plasticity and Formability of Annealed, Commercially-Pure Aluminum: Experiments and Modeling

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4285
Author(s):  
Jinjin Ha ◽  
Johnathon Fones ◽  
Brad L. Kinsey ◽  
Yannis P. Korkolis
Keyword(s):  
Yield Criterion ◽  
Pure Aluminum ◽  
Plastic Anisotropy ◽  
Rate Sensitivity ◽  
Hydraulic Press ◽  
Image Correlation ◽  
Forming Limit ◽  
Isotropic Hardening ◽  
Commercially Pure ◽  
Strain Paths

The plasticity and formability of a commercially-pure aluminum sheet (AA1100-O) is assessed by experiments and analyses. Plastic anisotropy of this material is characterized by uniaxial and plane-strain tension along with disk compression experiments, and is found to be non-negligible (e.g., the r-values vary between 0.445 and 1.18). On the other hand, the strain-rate sensitivity of the material is negligible at quasistatic rates. These results are used to calibrate constitutive models, i.e., the Yld2000-2d anisotropic yield criterion as the plastic potential and the Voce isotropic hardening law. Marciniak-type experiments on a fully-instrumented hydraulic press are performed to determine the Forming Limit Curve of this material. Stereo-type Digital Image Correlation is used, which confirms the proportional strain paths induced during stretching. From these experiments, limit strains, i.e., the onset of necking, are determined by the method proposed by ISO, as well as two methods based on the second derivative. To identify the exact instant of necking, a criterion based on a statistical analysis of the noise that the strain signals have during uniform deformation versus the systematic deviations that necking induces is proposed. Finite element simulation for the Marciniak-type experiment is conducted and the results show good agreement with the experiment.

Assessment of Deep-Drawability of Mild Steel Sheets in Consideration of r-Value Change During Processing

1988 ◽  
Vol 110 (4) ◽  
pp. 376-383 ◽  
Author(s):  
N. Kawai ◽  
N. Hayashi ◽  
S. Matsui
Keyword(s):  
Mild Steel ◽  
Pure Aluminum ◽  
Plastic Anisotropy ◽  
Drawing Ratio ◽  
Deep Drawability ◽  
Steel Sheets ◽  
Aluminum Sheets ◽  
Commercially Pure ◽  
Strain Paths ◽  
R Value

In the previous study, it was found that the plastic anisotropy of commercially pure aluminum sheets changed during the deep-drawing process, and that this change influenced markedly the deep-drawability. In the present study we discuss the deep-drawability of mild steel sheets with a crystal structure different from aluminum. The following have been confirmed: (1) The limiting drawing ratio correlates positively and nonlinearly with average r value (r¯ value). (2) Fracture strength correlates positively with r¯ value as in the theory, but the relation between them is nonlinear. Maximum drawing load remains almost constant irrespective of r¯ value against the theory. These relations can be connected with the result of (1). (3) The relations in (2) can be explained by the r¯ value measured from sheets prestrained in equibiaxial tension and pure shear, which resemble the strain paths of fracture site at punch profile and flange, respectively. (4) The results of (2) and (3) are quite different from those of commercially pure aluminum sheets.

Sign in / Sign up

Export Citation Format

Share Document