In 2018, a well-known manufacturer for the automotive industry was working on two specific parts that would be used in several models for an OEM. Their design utilized stamped, vertical links that needed to be low in weight, something the company could achieve by using a stronger grade of steel. However, in doing so, a challenge would be created.
Risk of cracks and scrap
The high flanges of the design in combination with a high strength material would increase the risk of cracks in production and the company wanted to ensure the lowest scrap rate possible. Therefore, the search began for a material with high formability and consistent properties that could ensure productivity, fulfill OEM specifications as well as meet their cost target. A low scrap rate would also align with their sustainable focus as the use of less material means a reduced environmental footprint.
Turning to 3rd generation steel
The manufacturer approached the SSAB team for their expert resources in forming and metallurgy with automotive steels. The details were made in an AIDA press with rated power of 10000 resp. 12500 KN, and the tooling was made from tempered steel K340 with a PVD surface treatment. The thicknesses of the applications were 1.5mm and 2.2 mm. It was decided to run a trial with the new Docol 600DH-GI, a so-called 3rd generation steel.
The detailed name of the steel grade chosen is Docol CR330Y590T-DH-GI and it offers high performance for parts with stretched edges, preventing failures. In this case it also fulfilled the OEM standard. The trial went very well and the scrap rate came out to almost 0% due to a homogenous behavior from coil to coil that assured a streamlined production in the stamping line.
“The product development team at SSAB have pushed themselves to the limits to produce Docol 600DH-GI. The new grade has a higher FLD compared to ordinary DP steel and performs better in plane strain. In addition, the hole expansion performance is better for the DH grade,” says Matti Säily, Product Manager for metal-coated products at SSAB. “We are very pleased with the result and this is a good example of how we can help assure flawless production with advanced high-strength steel.”
The results achieved in this trial process are a good example of why close collaboration and early design support can increase efficiency. It shows that customers and suppliers who join forces and share expertise can meet, and exceed, the demands of the automotive industry.