42nd International Deep Drawing Research Group Conference - IDDRG 2023

Modern car bodies are constantly relying higher proportions of high and ultra-high strength steels. In the past, the increase in material strengths led to a conflict regarding the complexity of component geometries. Limits of material formability were reached and compromises had to be made in part design. By integrating application-oriented problems into the material development, these limits...

The third generation of AHSSs (3rd Gen-AHSS) offers a good combination of strength and ductility due to the different micro-constituents inherited in the base material microstructure. However, the as-received material needs to be formed at high temperatures to form different parts in the body-in-white structure (BIW). Forming at high temperatures is crucial to reduce the press tonnage...

Tantalum RO5200 (TaRO5200) is an excellent and new emerging Bio-material with
wide applications. The most important property of TaRO5200 is Osseointegration which helps in integration of direct structural and functional connection between living bone and the surface. The process of forming in at actual is a plastic deformation where in the material is transforming in permanently is some shape...

The need for efficient mechanical component design has led the scientific community to evaluate the mechanical properties of anisotropic materials under multiaxial loadings. The mechanical behaviour of the aerospace grade AA2219 sheet was evaluated under planar biaxial stress conditions. The in-house designed cruciform specimen provides uniform strain and fracture in the gauge region. The load...

Aluminum alloys are being used extensively in the automotive industry to meet the increasing requirements for light weighting. The remarkable strength to weight ratio offered by aluminum alloys combined with good formability makes them suitable for manufacturing of light weight vehicles. Aluminum alloys of 5xxx and 6xxx series are particularly more important for applications in automotive and...

In recent decades deep drawing of 5xxx and 6xxx aluminum alloy sheets has increasingly been applied for producing lightweight car body components. Because of frictional heat the surface temperature of the drawing tools may notably increase during series production of these components, even though the deep drawing process is basically performed at room temperature. This work investigates the...

In sheet metal stamping, the occurrence of strain localization in a deformed sheet is considered the failure. As so, the formability of a sheet metal is conventionally evaluated by using the forming limit diagram. This study presents an evaluation method for detecting the strain localization during experiment based on the digital image correlation. The strain-field distribution on the surface...

In this study, the hole expansion tests are conducted for the first and third generation high-strength steels (dual-phase steel and quenching & partitioning steel) to investigate the edge fracture behavior. Two edge conditions based on separated manufacturing techniques (waterjet/wire cutting and punching) are prepared and then followed by hole expansion tests to characterize the edge...

One limitation of the standardized ISO 16630 hole expansion test is that it provides only one result: limiting hole expansion ratio (HER). In practice, steels with similar HER-values can have different cut edge forming behavior due to possible differences in strain localization tendencies. Digital image correlation (DIC) strain measurement during formability testing allows more in-detail...

The effect of strain gradient on the stretch flange deformation limit of steel sheets was investigated by hole expansion test under some forming conditions and by FEM. Hole expansion ratio was changed by changing initial hole diameter and punch shapes. It was clarified that limit deformation strain increases as it does not depend on initial hole diameter or punch shape, and thus strain...

Aluminum lithium alloy with many excellent properties such as low density, high elastic modulus, high specific strength has been considered as the most ideal structural material for aerospace. However, the application of Al-Li alloys is always limited in complex structural components, due to its inferior plasticity at room temperature and easy cracking during cold forming. As a novel forming...

Keywords: Sheet metal forming, high strength steels, Edge formability, Chassis, Pre-strain, Hole tension test

Abstract

There is a high level of uncertainty in the prediction of edge cracking during the design and manufacturing of high strength sheet metal products. Edge ductility is a complex parameter to measure since it is not an intrinsic property of the material, but...

The use of aluminium alloys with high mechanical properties is very interesting to reduce the weight of parts, especially in the automotive field. However, a formability problem prevents the use of these alloy at room temperature (RT), especially for complex shapes where part failure occurs before complete drawing. The use of a warm forming process, which consists of heating the part between...

For decades, the ISO-16630 Hole Expansion Test (HET) has been the industry standard for expressing the edge formability of sheet metals through the Hole Expansion Ratio (HER). However, in recent years, this test has been criticized for its high scatter in results for repeated experiments. This scatter has been suspected to be caused by the operator-reliant post-processing of the test, or...

A medium Mn steel was fabricated by employing a vacuum induction furnace. After that, the steel was hot rolled in order to achieve a final thickness of 1.5 mm. The resultant microstructure of the sheet was composed of martensite and very little amount of austenite, the ultimate tensile strength in this condition was close to 1600 MPa with a negligible elongation. An intercritical annealing was...

The range of blank-holding force (BHF) for which successfully forming of AA1100 in three different tempers is investigated using a combination of experiments and analysis. The experiments involve circular blanks of three different diameters: 35 mm, 37 mm and 40 mm. The thickness of the blanks is 0.51 mm. These are drawn with a punch of 20 mm diameter, i.e., at drawing ratios of 1.75, 1.85 and...

The use of press-hardening steels (PHSs) in automotive bodies creates the opportunity of producing thinner but higher-strength components. PHS1800, a grade of PHSs with a strength level of around 1.8 GPa after hot stamping, is a candidate material for vehicle anti-intrusion structures. The current study aims to investigate the formability of this steel during the hot-stamping process. A novel...

The deployment of Press Hardened Steels (PHSs) in the Body-In-White structures that took place during the two last decades is at the origin of a breakthrough weight saving on vehicles while guaranteeing the safety requirements of the automotive industry. The production of parts with complex shapes and a high strength between 1500-2000MPa was made possible by taking advantage of the hot...

Abstract: The thin-walled cylindrical parts with ribs, as the main structure of the launch vehicle, has been currently used in block manufacturing mode, which has the disadvantages of long manufacturing cycle, low material utilization rate and limited structural lightweight. Therefore, the integral forming process of the thin-walled cylindrical parts with ribs is an inevitable development...