The Effect of Strain Rate on the Strain to Fracture of a Sheet Steel Under Biaxial Tensile Stress Conditions

1982 ◽  
Vol 104 (2) ◽  
pp. 102-106 ◽  
Author(s):  
P. Broomhead ◽  
R. J. Grieve
Keyword(s):  
Strain Rate ◽  
Sheet Steel ◽  
Low Carbon Steel ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Bulge Test ◽  
Low Carbon ◽  
Forming Limit Curve ◽  
Biaxial Tensile Stress ◽  
Preliminary Study

The present investigation was undertaken as a preliminary study into the influence of strain rate on the forming limit diagram for low carbon steel. For a variation in strain rate from 10−3 s−1 to 70 s−1 experiments have shown that, in the positive quadrant of the forming limit diagram, the position of the forming limit curve is lowered with increasing strain rate. Further, it is suggested that a degree of correlation exists between strain rate and the work hardening exponent “n,” and as such the influence of strain rate on the forming limit diagram manifests itself through the change in n value. Slow speed forming was carried out under oil pressure using a bulge test with elliptical dies. To attain higher strain rate a water-hammer forming technique was employed together with the same die sets as those used for bulge forming.

Formability of Aluminum Alloy Sheets

1975 ◽  
Vol 97 (1) ◽  
pp. 66-73 ◽  
Author(s):  
S. S. Hecker
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Sheet Steel ◽  
Laboratory Data ◽  
Low Carbon Steel ◽  
Weight Ratio ◽  
Forming Limit ◽  
No Production ◽  
Low Carbon ◽  
Wide Range

High strength-to-weight ratio materials are becoming of increasing importance in the automotive industry. Some aluminum alloy sheets offer strength equivalent to low-carbon sheet steel at one third of the weight. However, for these alloys no production stamping experience exists and little meaningful laboratory data have been accumulated. This study was conducted to provide such laboratory information. Complete tensile properties and forming limit curves (FLC), as measured by a laboratory technique developed by the author, were determined for the aluminum alloys with a wide range of properties and were compared to the properties of low-carbon steel. All the aluminum alloys were found to have lower FLC’s, lower r values and equal or lower strain hardening capacities than sheet steel. Therefore their formabilities will be less than those of steel for all modes of sheet forming. This predicted press performance was verified for some of these alloys in limited press trials on a deck lid (inner panel) stamping.

scholarly journals Influence of the Laser Heat Treatment on the AA5754-H32 strain path during hydraulic bulge tests

2021 ◽  
Author(s):  
Angela Cusanno ◽  
Shanmukha Moturu ◽  
David Carty ◽  
Gianfranco Palumbo
Keyword(s):  
Strain Path ◽  
Forming Limit Diagram ◽  
Local Heat ◽  
Forming Limit ◽  
Bulge Test ◽  
Forming Limit Curve ◽  
Hydraulic Bulge ◽  
Strain Paths ◽  
The Right

The hydraulic bulge test represents an effective experimental method to characterise sheet metals since the equivalent strains before failure are much larger than those measured during tensile testing and there is nearly no frictional effect on the results. Recently this test has been proposed not only for extracting data concerning the equi-biaxial strain condition, but to determine the forming limit diagram (FLD) in the range of positive minor strains. In the proposed methodology, different strain paths can be obtained by merely using a test blank having two holes with a suitable geometry and position to be tested, without the need of dies with elliptical apertures. However, a carrier sheet is necessary, thus implying results may be affected by friction effects. This paper proposes a new methodology for the determination of the right side of the Forming Limit Curve (FLC), based on the adoption of local heat treatments aimed at determining different strain paths on the blank to be tested while using the classical circular die for bulge tests. In particular, the formability of the alloy AA5754-H32 was investigated; 3D Finite Element simulations were conducted setting different laser strategies and monitoring the resulting strain path. Results revealed that the proposed methodology supports obtaining many additional points in the right side of the FLC, thus being effective and friction free.

scholarly journals SIMULATION OF MULTI-STAGE COLD FORMING OF A THIN-WALLED VESSEL

2020 ◽  
Vol 82 (1) ◽  
pp. 75-88 ◽  
Author(s):  
I.E. Keller ◽  
A.V. Kazantsev ◽  
A.A. Adamov ◽  
D.S. Petukhov
Keyword(s):  
Numerical Model ◽  
Sheet Steel ◽  
Forming Limit ◽  
Low Carbon ◽  
Limit Curve ◽  
Forming Limit Curve ◽  
Cold Forming ◽  
Coordinate Grid ◽  
Thin Walled ◽  
Press Equipment

The method of construction and attestation of a numerical model of cold stamping of thin-walled products made of anisotropic metal sheet for the design of technological operations is proposed. The relations of the associated law of plastic flow with the Barlat flow function and isotropic strain hardening are used. The method of design and processing the experiment is proposed for their identification. The forming limit curve is approximated numerically by the Marciniak - Kuczynўski method, and for its identification it is proposed to use a failure test under uniaxial tension and press equipment as an experimental. To do this, a coordinate grid is applied to a flat blank by laser engraving, whose distortions near the zones of strain localization and failure of the vessel give additional points of the forming limit curve. The constants of the Peng - Landel potential are found to describe the elasticity of a polyurethane die under large deformations using tests for free and constrained compression. All tests according to the method were performed for low-carbon sheet steel DC04EK 0.7 mm and SKU-PFL polyurethane. A numerical model of the process in the LS-DYNA package is designed using material models from its library. The calculations according to the model were confirmed by experiment, for which the main deformations were determined by the distorted coordinate grid on the workpiece after each operation at the control points. The calculation of the sequence of stages of stamping, drawing and bulging of the workpiece in the production of the vessel with and without intermediate annealing is performed and the dangerous zones and mechanisms of their formation are determined.

WEIRKOTE PLUS

Alloy Digest ◽  
1987 ◽  
Vol 36 (6) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Carbon Steel ◽  
Physical Properties ◽  
Deep Drawing ◽  
Sheet Steel ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Steel Corp ◽  
Coated Sheet

Abstract WEIRKOTE PLUS is a Galfan-coated sheet steel. The sheet is conventional low-carbon steel normally used for galvanized sheets and strip. This digest will concentrate on the characteristics and properties of the Galfan coating which is nominally a 95% zinc-5% aluminum alloy. The coating on Weirkote Plus is ideal for a variety of tough applications. It is excellent for products that require deep drawing and it combines extra corrosion resistance with superior formability. This datasheet provides information on composition and physical properties. It also includes information on corrosion resistance as well as forming, joining, and surface treatment. Filing Code: Zn-41. Producer or source: Weirton Steel Corp.

Formability Analysis of AA6061 Sheet in T6 Condition

2015 ◽  
Vol 766-767 ◽  
pp. 416-421
Author(s):  
S. Vijayananth ◽  
V. Jayaseelan ◽  
G. Shivasubbramanian
Keyword(s):  
Experimental Method ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Ansys Software ◽  
Limit Curve ◽  
High Corrosion Resistance ◽  
Forming Limit Curve ◽  
Drawing Test ◽  
Deep Drawing Test ◽  
Alloy 6061

Formability of a material is defined as its ability to deform into desired shape without being fracture. There will always be a need for formability tests, a larger number of tests have been used in an effort to measure the formability of sheet materials. Aluminium Alloy 6061 is a magnesium and silicon alloy of aluminium. It is also called as marine material as it has high corrosion resistance to seawater. In this paper Formability test of AA6061 sheet is done by Forming Limit Diagram (FLD) Analysis. FLD or Forming Limit Curve (FLC) for the forming processes of AA6061 sheets is obtained by Experimental method and FEM. Experimental method involves Deep drawing test of the sheet and ANSYS software is used for FEM.

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