Investigations on Semi-solid Joined Steel Components and their Bonding Quality

Abstract

To characterise the bonding quality of semi-solid joined components, fundamental investigations were carried out by producing composite test specimens. By using steel as a semi-solid base matrix and different steel or copper alloys as inserted materials, an interesting field of material combinations was realised. Two different steel grades, the cold forming tool steel X210CrW12 and the bearing steel 100Cr6, were chosen as the material of the base matrix. Geometry variations were tested along with the variation of materials mentioned. The results supply information about the influence of the inserts shape on an early cooling of the base material during form filling or remelting of the insert caused by overheating. Qualitative and quantitative analyses of the mechanical characteristics of the bonding were carried out using mechanical tests. Metallographic analyses complete the description of the bonding mechanisms at the contact zone between the solidified matrix and the insert. The investigations on basic geometries show a good joining quality, which is mainly based on a strong force and form closure caused by contraction of the solidifying and cooling base matrix. In addition, material closure occurs in areas that are strongly heated during the joining process. These results provide key information for the design of prospective components of a new generation.