Effect of forming parameters on the fracture behaviour of AISI 430 steel in draw-bend fracture test

The draw-bend fracture (DBF) test was used to simulate the different forming conditions of AISI 430 steel strips with thickness of 0.8 mm. The tests were performed for varying test parameters such tool radius, drawing speed and strip orientation. The analysis of variance (ANOVA) at α = 0.05 significance level was used to determine the relationship between the test parameters and the major strain, the total elongation and the thickness reduction of samples as well as the coefficient of friction. A comparative analysis of the DBF test results revealed that parameters related to specimen deformation changed with an increasing tool radius to thickness (R/t) ratio. However, no statistically significant effect of drawing speed or strip orientation on major strain and thickness reduction was observed. The value of total elongation increased with increasing R/t ratio. An increase in drawing speed resulted, for both analyzed strip orientations, in a reduction of the coefficient of friction. Over the entire range of analyzed sliding speeds and R/t ratios, the coefficient of friction for sheets oriented along the sheet rolling direction was higher than that for specimens cut in the transverse direction.