The Influence of Heat Treatment on the Microstructure, Surface Roughness and Shear Tensile Strength of AISI 304 Clinch Joints

Clinching is the manufacturing process of joining two or more metal sheets under high plastic deformation by form and force closure without thermal support auxiliary parts. Clinch connections are applicable to difficult-to-join hybrid material combinations, such as steel aluminum. Therefore, this technology interesting for application AISI 304 components, widely used a highly formable sheet material. A characteristic feature its metastability, i.e., face-centered cubic (fcc) γ-austenite can transform into significantly stronger body-centered (bcc) α’-martensite deformation. This work investigates effect heat treatment—a that involves formation an oxidation layer on surface—on forming during resulting mechanical properties clinch joints made from 304. For purpose, different non-heat treated heat-treated were examined using classical metallography advanced SEM techniques, accompanied further investigations, hardness feritscope measurements. The shear tensile strength was determined, fracture behavior samples investigated. Clear influences heat-treatment-induced surface roughness joint geometry observed.