This blog post introduces a new series of articles coming out of the French AutoForm world. Below you’ll see real results for the simulation of hotforming of aluminum alloys .
Today’s featured metal forming company is Constellium, a leading supplier in design and fabrication of innovative aluminum products. While forming of such parts is a hot topic in automotive stamping today, it poses a number of challenges for many manufacturers, which we address with this inside story.
Presently the Constellium group runs twenty-two production sites throughout Europe, North America and China. Its research center located in Voreppe, France, has become a cradle of advanced aluminum solutions in the packaging, aerospace and automotive industries.
For the automotive industry, Constellium has developed a complete range of products for body in white hang-on parts, helping car manufacturers and suppliers to design lighter vehicles. Their particular support is geared towards improving fuel consumption and reducing the carbon footprint.
In addition to their already existing solutions adapted to structural parts, such as Strongalex© and Securalex©, Constellium develops new high strength alloys (series 6xxx) and ultra-high strength alloys (series 7xxx): Ultralex©.
In order to form parts made from Ultralex®, Constellium performs internal as well as external experimental phases – with the help of suppliers or manufacturing partners – on the hot forming technology using a sheet treatment ranging from 400 to 500°C.
Thus, the hot forming process of a B-pillar at Constellium starts with the heating of the blank over several minutes to a temperature that is close to that needed for the process.
After the metal sheet is transferred into the press, it is stamped using room temperature tools (“cold”) then quenched with those tools still closed.
Under these lab conditions at Constellium, the complete forming cycle lasts less than 20 seconds while the whole heating process requires 8 minutes per batch.
The Constellium Research Center in Voreppe has been equipped with AutoForm stamping simulation software since 2011. It More specifically Constellium uses the hot forming simulation software AutoForm-ThermoSolver®plus to get the job done, while validating the relevance of the simulation correlating with press try-outs.
Here, they fully utilize simulation software in order to bring added value to their customers by demonstrating the hot forming simulation of their innovative alloys for real-life stamped parts.
The minimal set of data items required to carry out a simulation with AutoForm are:
- Flow stress curves obtained at different temperatures,
- Thermal material parameters (thermal capacity, conductivity, etc.),
- Thermal exchange parameters.
Beyond this, there are far more options given to customize models describing the forming behavior of any kind of aluminum alloys. These options involve the description of the yield loci, FLDs or even temperature dependent r-values in order to specify the material. For a thorough understanding of the process conditions we highly recommend to review one of our recently published posts addressing the warm- and hotforming of Aluminum-alloys. In principle all tools and the various steps are taken into account during the process definition.
After the simulation of the hot forming process, AutoForm-ThermoSolver®plus provides numerous result variables and allows for the display, for example, of the temperature history in the stamping throughout the manufacturing process (see image below).
Constellium observes a good correlation between calculation results and experimentally measured values, as seen here-below for instance: a comparison of the thickness distribution between real measurements and simulation results (results in red and measurements in white). With AutoForm-ThermoSolver®plus, Constellium can therefore adopt a specific course for the marketing of its innovative products. Indeed, the work of the Voreppe Research Center confirms the advantages and the added value in using the digital technology for the group’s customers, assuring them the possibility to simulate their hot forming processes using Constellium’s innovative aluminum alloys.
According to Constellium, by using AutoForm-ThermoSolver®plus, they can now adopt a specific course for the marketing of their innovative products.
Read our earlier post on aluminum warm and hotforming HERE.