Chemical joining of aluminum to steel parts is one of the main challenges in the automotive industry to achieve sound economical solutions for required automobile weight reduction. The cold metal transfer (CMT) is a fusion welding process developed to meet that challenge. It is shown in this paper how the choice of proper filler materials can yield appropriate mechanical performance of specially designed dissimilar CMT butt joints by improving the seam characteristics and weld bead properties.

The cover shows the inverse pole figure map obtained by EBSD on the cross section of an hybrid aluminium‐to‐steel joint produced by the Cold Metal Transfer welding technique on a specially designed butt geometry…More details can be found in the article of L. Agudo et al. .

During heat treatment of cladded steel composites, element redistribution may occur between the various plating materials. Depending on alloy composition and the particular time–temperature profile, Carbon (C) diffusion between the plating materials is observed. Herein, C diffusion between different layers of roll‐cladded steel composites during typical production routes is numerically simulated with the thermokinetic software package MatCalc. Two material combinations, 340LA–22MnB5 and 340LA–34MnB5, are compared with experimental results of large‐scale manufactured steel composite material at different production steps, from hot strip to hardened cold strip material. The simulation agrees qualitatively and quantitatively well with the experimental results. It is demonstrated that even short heat treatment intervals can have significant influence on the C redistribution within the steel composite.

Cladding of steel is mainly carried out by hot rolling. This process is very labor-intensive and, therefore, expensive. Cold plating has been used successfully to produce bimetals and could also be an alternative manufacturing process for cladded carbon steel composites. So far, however, only thin narrow IF-steels sheets were successfully cold plated. Different pretreatments and process windows have been used to successfully produce a cold roll-cladded composite of various steel grades on a cold rolling test facility. While joining two similar steels was relatively easy, the combination of different steel alloy compositions was more difficult. Higher necessary forces and edge cracks complicated the experiments. A slight warming of the sheets before joining had a positive effect on the production of the composite. From today's perspective, the required high rolling forces do not allow scaling up to large-scale production.