Effects of Stress Relieving on Limit Dome Height of Titanium Tailor-Welded Blanks at Elevated Temperatures

2006 ◽  
pp. 977-980
Author(s):  
Chi Ping Lai ◽  
Luen Chow Chan ◽  
Chi Loong Chow
Keyword(s):  
Elevated Temperatures ◽  
Dome Height ◽  
Limit Dome Height ◽  
Tailor Welded Blanks ◽  
Stress Relieving ◽  
Effects Of Stress

Effects of Stress Relieving on Limit Dome Height of Titanium Tailor-Welded Blanks at Elevated Temperatures

2006 ◽  
Vol 532-533 ◽  
pp. 977-980 ◽  
Author(s):  
Chi Ping Lai ◽  
Luen Chow Chan ◽  
Chi Loong Chow
Keyword(s):  
Room Temperature ◽  
Elevated Temperatures ◽  
Heating System ◽  
Dome Height ◽  
Control Panel ◽  
Blank Holder ◽  
Limit Dome Height ◽  
Tailor Welded Blanks ◽  
Heat Treated ◽  
Stress Relieving

This paper aims to study the effect of stress relieving on Limit Dome Height (LDH) of Ti-TWBs at elevated temperatures. This is achieved by developing a newly constructed heating system. The elevated temperature of the system can be varied and monitored by a separately control panel. All Ti-TWBs were prepared and used to examine the LDHs under elevated temperatures. Selected specimens were heat-treated at 600°C within an hour before being formed by HILLE machine. Meanwhile, the temperature of tool heating system was also adjusted from room temperature to 550°C. Specified tests were carried out to examine the stress relieving effects of Ti-TWBs on the LDHs with the temperature control panel. In addition, investigations were carried out to ascertain whether the elevated temperatures of the critical tooling components, i.e. the die and the blank holder, could result in any significant effects on LDHs of Ti-TWBs. The findings show that LDHs of Ti-TWBs can be improved by stress relieving. The stress relieving condition can be obtained by nearly isothermal forming of specimens at a range of 550°C to 600°C.

Limit dome height and failure location of stainless steel tailor-welded blanks

2007 ◽  
Vol 221 (12) ◽  
pp. 1497-1506 ◽  
Author(s):  
M Jie ◽  
C H Cheng ◽  
C L Chow ◽  
L C Chan
Keyword(s):  
Numerical Simulation ◽  
Stainless Steel ◽  
Dome Height ◽  
Forming Limit ◽  
Forming Limits ◽  
Limit Dome Height ◽  
Localized Necking ◽  
Tailor Welded Blanks ◽  
Necking Criterion ◽  
Failure Location

Forming limits of stainless steel tailor-welded blanks (TWBs) are investigated through both testing and numerical simulation. Limit dome height (LDH) tests were performed for 1.2/1.0 mm TWBs with 0°, 90°, 45° weldment orientations and various blank widths. Numerical simulation of the LDH test was conducted with LSDYNA. Since TWB is, in reality, a structure, the forming limits of TWBs in terms of the LDH and failure location should be characterized rather than the conventional forming limit diagrams (FLDs). A localized necking criterion based on the vertex theory was employed to identify the failure sites of TWBs. The localized necking criterion was compiled into a computer program, which processed the output data from LSDYNA. The LDHs and failure locations were computed for various combinations of blank thickness and weldment orientation. The predicted LDH and failure locations were compared with the test results and found to be satisfactory.

scholarly journals Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 875
Author(s):  
Jie Wu ◽  
Yuri Hovanski ◽  
Michael Miles
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Plastic Strain ◽  
Finite Element Model ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dome Height ◽  
Tailor Welded Blanks ◽  
Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

Forming Behaviour at Elevated Temperature of a Laser Heat-Treated AZ31 Magnesium Alloy Sheet

2018 ◽  
Vol 941 ◽  
pp. 1270-1275
Author(s):  
Donato Sorgente ◽  
Gianfranco Palumbo ◽  
Alessandro Fortunato ◽  
Alessandro Ascari ◽  
Ali Arslan Kaya
Keyword(s):  
Magnesium Alloy ◽  
Heat Input ◽  
Elevated Temperatures ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Dome Height ◽  
Magnesium Alloy Sheet ◽  
Laser Heat ◽  
Az31 Magnesium Alloy Sheet ◽  
Forming Behaviour

The tailoring of mechanical and technological properties of the initial material in sheet metal forming has been widely investigated and successfully applied. The benefits of such an approach can be found in the improvement of both the post-forming performances of the manufactured component and the forming process capabilities. Different strategies can be found and most of them involve a microstructural alteration by a selective heat source (e.g. laser, induction, UV light). The use of aluminium alloys combined with these strategies has been extensively investigated, while magnesium alloys are almost not yet considered from this viewpoint. In this work, we investigated the effect of a selective laser heat treatment on an AZ31 magnesium alloy sheet. After laser heat treating a single track in the centre of a blank with different heat input values, bulge tests at elevated temperatures were conducted. The dome height evolution was continuously acquired during the tests and differences between the untreated specimen and the laser treated ones have been characterized. The effect of the laser treatment was evaluated also in terms of thickness distribution of the formed specimens. A thickness discontinuity was found along the treated specimens in the transition zone between the treated and the untreated material. Results highlighted that an effective change in the forming behaviour can be induced in the treated zone depending on the laser heat input. It has thus been shown that this approach can be employed for tailoring the magnesium alloy blank properties prior to the gas forming at elevated temperatures.

Experimental Study on the Mechanical Property and Forming Limit of Magnesium Sheet at Elevated Temperatures

2009 ◽  
Author(s):  
Y. Huang ◽  
J. Huang ◽  
J. Cao
Keyword(s):  
Elevated Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Tensile Tests ◽  
Alloy Sheet ◽  
Dome Height ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Magnesium Sheet

Magnesium alloy sheet has received increasing attention in automotive and aerospace industries. It is widely recognized that magnesium sheet has a poor formability at room temperature. While at elevated temperature, its formability can be dramatically improved. Most of work in the field has been working with the magnesium sheet after annealed around 350°C. In this paper, the as-received commercial magnesium sheet (AZ31B-H24) with thickness of 2mm has been experimentally studied without any special heat treatment. Uniaxial tensile tests at room temperature and elevated temperature were first conducted to have a better understanding of the material properties of magnesium sheet (AZ31B-H24). Then, limit dome height (LDH) tests were conducted to capture forming limits of magnesium sheet (AZ31B-H24) at elevated temperatures. An optical method has been introduced to obtain the stress-strain curve at elevated temperatures. Experimental results of the LDH tests were presented.

scholarly journals Mechanical Properties of Steels for Cold-Formed Steel Structures at Elevated Temperatures

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhen Nie ◽  
Yuanqi Li ◽  
Yehua Wang
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Elasticity Modulus ◽  
Mechanical Performance ◽  
Strain Curve ◽  
Steel Structures ◽  
Test Method ◽  
Stress Relieving ◽  
Cold Formed Steel

It is highly important to clarify the high-temperature mechanical properties in the design of cold-formed steel (CFS) structures under fire conditions due to the unique deterioration feature in material properties under fire environment and associated reduction to the mechanical performance of members. This paper presents the mechanical properties of widely used steels for cold-formed steel structures at elevated temperatures. The coupons were extracted from original coils of proposed full annealed steels (S350 and S420, with nominal yielding strengths 280 MPa and 350 MPa) and proposed stress relieving annealed steels (G500, with nominal yielding strength 500 MPa) for CFS structures with thickness of 1.0 mm and 1.2 mm, and a total of nearly 50 tensile tests were carried out by steady-state test method for temperatures ranging from 20 to 700°C. Based on the tests, material properties including the yield strengths, ultimate strengths, the elasticity modulus, and the stress-strain curve were obtained. Meanwhile, the ductility of steels for CFS structures was discussed. Then, the temperature-dependent retention factors of yield strengths and elasticity modulus were compared to those provided by design codes and former researchers. Finally, a set of prediction equations of the mechanical properties for steels for CFS structures at elevated temperatures was proposed depending on existing tests data.

Comparison of different welding methods on mechanical properties and formability behaviors of tailor welded blanks (TWB) made from AA6061 alloys

2020 ◽  
pp. 095440622095250
Author(s):  
Behrouz Bagheri ◽  
Mahmoud Abbasi ◽  
Reza Hamzeloo
Keyword(s):  
Mechanical Properties ◽  
Laser Welding ◽  
Co2 Laser ◽  
Forming Limit Diagram ◽  
Dome Height ◽  
Forming Limit ◽  
Welding Parameters ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Different Characteristics

A tailor welded blank (TWB) includes two or more blanks joined together in order to make a single blank. Different welding methods are used to join blanks with different characteristics and form TWBs. In this study, a comparison is made among the effects of three different welding methods namely CO2 laser welding, friction stir welding (FSW), and friction stir vibration welding (FSVW) on mechanical and formability properties of developed TWBs. AA6061 alloy sheets with different thicknesses (1.2 and 0.8 mm) are joined to get TWBs. The forming limit diagram (FLD) and limiting dome height (LDH) are applied to assess the formability. The Taguchi method is applied to find the optimum values of welding parameters. It is concluded that TWBs made by FSVW have higher mechanical properties and formability compared to TWBs made by FSW and CO2 laser welding. The results also indicate that FLD for TWBs made by FSW is higher than FLD for TWBs made by CO2 laser welding and FLD0, for TWBs made by FSVW, increases as vibration frequency increases.

Effect of Weld Location, Orientation, and Strain Path on Forming Behavior of AHSS Tailor Welded Blanks

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
S. K. Panda ◽  
J. Li ◽  
V. H. Baltazar Hernandez ◽  
Y. Zhou ◽  
F. Goodwin
Keyword(s):  
Plane Strain ◽  
Weld Line ◽  
High Strength ◽  
Deformation Mode ◽  
Dome Height ◽  
Manufacturing Cost ◽  
Stretch Forming ◽  
Material Combination ◽  
Tailor Welded Blanks ◽  
The Difference

Use of multiple advanced high strength steel sheets for fabrication of tailor welded blanks (TWBs) is one of the current interests for automotive and steel industries as it reduces manufacturing cost and weight of the vehicle, and also improves the quality of the component. As the varieties of TWB applications are increasing, the effects of the difference in material properties, weld, and its orientation on blank formability have become important both in deep drawing and stretch forming. In this work, high strength low alloy (HSLA) grade steels were laser welded with two different dual phase steels having 980 MPa (DP980) and 600 MPa (DP600) tensile strengths to fabricate two different material combination TWBs (DP980-HSLA and DP600-HSLA). Formability of these two types of TWBs has been studied experimentally both in biaxial and plane strain stretch forming modes by performing limiting dome height (LDH) tests using a 101.6 mm diameter hemispherical punch. Five different weld locations during biaxial-stretch forming mode, and the effect of weld orientation with respect to major principal strain in plane strain stretch forming mode, have been studied. It was found that formability LDH and failure location depended on weld location, and LDH increased when weld line was positioned at the extreme positions away from the center due to more uniform strain distribution on the deformed dome. The welded blanks had lower formability in plane strain deformation mode compared with biaxial-stretch forming mode. However, influence of weld orientation on the formability depended on material combination. Changes in the fracture mode were confirmed from fractography analysis of biaxial, transverse plane strain, and longitudinal plane strain stretch formed samples.

Microstructual Analysis of Stress Relieving on the Thermal Deformation Behaviors of Titanium Tailor-Welded Blanks

2013 ◽  
Vol 677 ◽  
pp. 169-172
Author(s):  
Chi Ping Lai ◽  
Luen Chow Chan
Keyword(s):  
Heat Treatment ◽  
Thermal Deformation ◽  
Room Temperature ◽  
Cold Working ◽  
Working Temperature ◽  
Tailor Welded Blanks ◽  
Working Stress ◽  
Heating Device ◽  
Stress Relieving ◽  
Deformation Behaviors

This paper aims to investigate the microstructual analysis of titanium tailor-welded blanks (Ti-TWBs) undergoing the stress relieving (SR) during a thermal deformation. A modified HILLE machine, with a specific heating device that can adjust the working temperature, was employed in this study. Qualified Ti-TWBs specimens were prepared in different widths and lengths. In order to compare the performance of both SR and non-SR Ti-TWBs, the formability analyses at room temperature and around 550degC were then carried out accordingly. The limit dome heights (LDH) of these specimens were measured and it was found that the ductility of the SR Ti-TWBs was improved due to the removal of the hardening effect as well the working stress during the cold working. Moreover, the fracture surface of the Ti-TWBs also revealed that the microstructure was fine and equaxial after the heat treatment. It can be concluded that the microstructual evolution is useful to enhance the strength of Ti-TWBs.

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