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

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.

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A Consideration on Deep-Drawability of Commercially Pure Aluminum Sheets

Journal of Engineering for Industry ◽

10.1115/1.3186013 ◽

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.

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

Materials ◽

10.3390/ma13194285 ◽

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.

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Effect of Intermetallic Compound Layer on Bond Strength of Friction-welded Interface of Commercially Pure Aluminum to Mild Steel

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY ◽

10.2207/qjjws.23.622 ◽

2005 ◽

Vol 23 (4) ◽

pp. 622-627 ◽

Cited By ~ 12

Author(s):

Naotsugu YAMAMOTO ◽

Makoto TAKAHASHI ◽

Masatoshi ARITOSHI ◽

Kenji IKEUCHI

Keyword(s):

Intermetallic Compound ◽

Bond Strength ◽

Mild Steel ◽

Pure Aluminum ◽

Compound Layer ◽

Intermetallic Compound Layer ◽

Commercially Pure

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

Journal of Engineering for Industry ◽

10.1115/1.3187139 ◽

1987 ◽

Vol 109 (4) ◽

pp. 355-361 ◽

Cited By ~ 14

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.

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EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL

Jurnal Sains Materi Indonesia ◽

10.17146/jsmi.2020.21.2.5799 ◽

2020 ◽

Vol 21 (2) ◽

pp. 89

Author(s):

Iskandar Muda ◽

Azwar Manaf

Keyword(s):

Industrial Process ◽

Slow Heating ◽

Strain Hardening Exponent ◽

Low Carbon ◽

Normal Anisotropy ◽

N Value ◽

Deep Drawability ◽

Steel Sheets ◽

Batch Annealing ◽

R Value

EFFECT OF ANNEALING CYCLES ON DEEP DRAWABILITY OF LOW CARBON TITANIUM ADDED STEEL. Maximum mechanical properties and deep drawability of low carbon titanium added steels was obtained after heat treatment with simulation batch annealing cycles in an industrial process. The effect of holding times and holding temperatures on deep drawability were studied using tensile test for measuring normal anisotropy (r-value) and strain hardening exponent (n-value). Scanning electron microscope were employed for observation of microstructure in steel sheets. X-ray diffraction with pole figure techniques were also used for measuring texture of annealing. Results showed that as the temperature was increased up to 900 oC, both r and n values increased gradually and peaked in the temperature of 850 oC. This results showed that formability of sheet materials increased until batch annealing temperature reach 850 oC as increasing the ratio of intensities {111} /{100}. The largest mean r value of almost 2.6 was obtained in slow heating at holding temperature of 850 oC with n value of 0.27.

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