Experimental Investigation of Process Forces and Part Quality for Fine Blanking of Stainless Steel with Inductive Heating

Abstract

Fine blanking is a highly productive process of industrial mass production with which high quality components in particular but not exclusively for the automotive industry are produced. The manufacturing process faces its limits at elevated tensile strengths of the materials to be processed. Consequently, high-strength steels can currently only be fine blanked to a limited extent. This can be overcome by lowering the flow stress of high-strength steels by means of inductive heating. A steel of high importance especially for industries with high hygiene standards such as medical and nutrition production is the stainless steel X5CrNi18-10 (1.4301). As a metastable austenitic steel which can initiate cutting impact on the press through martensitization, fine blanking of stainless steel is a challenge. X5CrNi18-10 is not a high-strength steel per se but becomes difficult to process due to the high hardness of the martensite phase, known as transformation-induced plasticity (TRIP) effect. Thus, in order to combine the possible advantages of the fine blanking process with inductive heating and the important properties of stainless steel, fine blanking of this steel was investigated with inductive heating prior to the fine blanking. The process forces and product quality properties such as die roll were investigated and found to be advantageous in comparison to non-heated fine blanking specimens of the same steel. The process forces and the die roll height decreased due to the heating.

Design of a new simulative tribotest for warm forming applications having high contact pressure and surface enlargement

“…Later in Esaform 2021, same group presented the cutting forces at different temperatures for the X5CrNi18-10 (AISI 304) stainless steel. In the same paper, final product tolerances and cutting surface quality of different temperatures were also analysed [6]. Finally, in Esaform 2022, the same research group, presented the results obtained when fine blanking a star shape component and the 40MnB4 and 42CrMo4 steels.…”

A Model Calculation of CO2 Emissions Saving Potential for Fine Blanking of Inductively Heated Sheet Metal with Comparison of the Product Variants

“…As a further consequence of heat introduction beyond lightweight construction gains, a reduction of die roll is to be expected. [4] This implies the possibility to gain further energetic saving opportunities and better material utilization by means of diminution or elimination of downstream manufacturing processes. The focus of the work is on the ecological and energetic consideration of the production process of fine blanked components and the comparison of the conventional fine blanking with fine blanking of inductively heated sheet metal.…”

“…The thusly determined cutting forces are given in Table 1. The process forces in fine blanking of steel can be reduced by heating the metal sheet [4]. To compare the force values with the force values after inductive heating of the sheet, a temperature factor was used to adjust the yield strength of the materials.…”

“…It is assumed that a heating to not more than 500 °C is sufficient to lower the flow stress of the steels but not so high as to initiate undesired changings in the metal crystal lattice. The dependency of metal sheet temperature and fine blanking process forces have been investigated before for different steels [4]. The results of the calculations are given in Table 3.…”

Fine Blanking Limits of Manganese-Boron-Steel in Fine Blanking Compared to Tempered Steel with Variation of Sheet Metal Temperature

“…The tests were repeated ten times each. This procedure has already been described [14]. All experiments were carried out with subsequent single strokes.…”