Influence of drawing speed and anisotropy on the tribological behavior and fracture of an AISI 430Nb sheet steel

ABSTRACT

In sheet metal forming, mechanical properties of the material and aspects related to friction have been one of the main concerns, as they have a great influence on productivity, product quality and production costs. In this context, it is extremely important to understand and to be able to control the different factors that affect ­friction during the plastic deformation process. This study aims to investigate the influence of drawing speed and ­anisotropy on the tribological behavior and fracture of an AISI 430 ferritic stainless-steel strip stabilized with Nb sliding over a hard metal pin (WC-12%Co). A formability test that simulates the friction between the sheet and tool was used. The coefficient of friction, ductility and hardness in the fracture were measured to investigate the effect of drawing speed and anisotropy of the steel for the experimental results. A comparative analysis of the results revealed that the coefficient of friction due to increases surface roughness by roping effect. ­Furthermore, the orientation of the metallic strip influenced symptomatically on the friction, being higher in the rolling direction, which surface roughness was higher than the transverse direction. As a result of plastic deformation, the hardness and strength of the steel sheet increased, but the ductility decreased; however, the increase in ­drawing speed also influenced the values of these parameters causing a decrease, most probably, due to the increase temperature at the contact interface.

Keywords:
Sheet metal forming; Drawing speed; Anisotropy; Fracture; AISI 430