Profile straightening – Profile straightening in roll forming by partial rolling
In this project an innovative process for straightening roll forming profiles is developed. Since straightening operations in roll forming are currently still strongly experience-based and therefore less efficient, in this project a diagnosis tool is being developed which straightens profiles based on a calculation model of the longitudinal strain distributions. In this process, longitudinal strains are to be introduced selectively by partial rolling in order to homogenize the strain distribution and thus eliminate the profile errors. This influence is investigated both numerically and experimentally.
Current sustainability goals include efficient use of resources. As roll-formed products account for a large share of world steel production, one goal is to minimize waste in this sector. Furthermore, the development of the roll forming production process secures important fields of application for the material steel. This sector is currently experiencing increasing product diversification, whereby the demands on the flexibility of the production process and on set-up and straightening times are rising enormously. At the same time, there are uncertainties in the semi-finished product and thus fluctuating sheet properties, which in combination with the longitudinal elongations introduced in the process cause deviations of the geometry from straightness. This challenge leads to the goal of increasing the robustness of profile straightening and reducing straightening iterations to mitigate uncertainties in the economics and competitiveness of the process. In order to achieve the goal of reducing emissions and increasing economic efficiency, a reliable and efficient process for straightening profiles will be developed.
Within the scope of this project, numerical and experimental investigations are carried out to identify and quantify parameters influencing the longitudinal elongation and the deviations of the profile straightness. Geometric, material and process parameters are varied for this purpose. Based on the numerical and experimental findings, an analytical model is built to predict the longitudinal strain distribution. Based on this model, effective countermeasures are derived. In order to produce straight defect-free profiles, profiles with different geometries and materials are straightened using partial rolling. The procedure for developing the process and initial results are shown in Figure 1. Further investigations on the influence of process and material parameters will further optimize the partial rolling process.
The research work presented here takes place within the framework of IGF project no. 20960N VP1418 of the research association for steel Application (FOSTA), Düsseldorf, is supported by the Federal Ministry of Economic Affairs and Energy through the German Federation of Industrial Research Associations (AiF) as part of the program for promoting industrial cooperative research (IGF) on the basis of a decision by the German Bundestag.
Furthermore, we would like to thank all industrial partners who support the research project “Profile straightening by partial rolling” in the project accompanying committee.