Adiabatic Blanking: Influence of Clearance, Impact Energy, and Velocity on the Blanked Surface

Abstract

In contrast to other cutting processes, adiabatic blanking typically features high blanking velocities (>3 m/s), which can lead to the formation of adiabatic shear bands in the blanking surface. The produced surfaces have excellent properties, such as high hardness, low roll-over, and low roughness. However, details about the qualitative and quantitative influence of significant process parameters on the quality of the blanked surface are still lacking. In the presented study, a variable tool is used for a systematic investigation of different process parameters and their influences on the blanked surface of a hardened 22MnB5 steel. Different relative clearances (1.67% to 16.67%), velocities (7 to 12.5 m/s), and impact energies (250 J to 1000 J) were studied in detail. It is demonstrated that a relative clearance of ≤6.67% and an impact velocity of ≥7 m/s lead to adiabatic shear band formation, regardless of the impact energy. Further, an initiated shear band results in the formation of an S-shaped surface. Unexpectedly, a low impact energy results in the highest geometric accuracy. The influence of the clearance, the velocity, and the impact energy on the evolution of adiabatic shear band formation is shown for the first time. The gained knowledge can enable a functionalization of the blanked surfaces in the future.

A structural-thermal coupled modeling approach on the formation of adiabatic shear bands in steel sheet blanking process

“…In addition, a blankholder of the same clearance completes the test configuration, while the half domain is studied due to its cylindrical axisymmetric geometry as shown in Figure 1 which depicts the derived FE model developed in LS-DYNA software. Finally, a constant punch velocity of 3 m/s is applied securing adiabatic blanking conditions [1,2].…”

“…Due to its strong connection to dynamic failure, the ASB mechanism has been studied regarding its influence on peak force and fracture characteristics in case of adiabatic sheet blanking process. Winter et al [1] carried out a parametric analysis of clearance, punch velocity and impact energy on ASB formation in blanking of 22MnB5 hardened steel sheet, revealing an S-shaped shear band formulation, while also higher velocity and lower clearance increased material sensitivity against ASB occurance. Further, Schmitz et al [2] revealed that shear bands expand along S-shaped traces in case of adiabatic blanking of high-strength steels, also obtaining that material strain rate hardening behavior strongly affects the width and hardness of ASB.…”

Numerical Investigation of the Damage Effect on the Evolution of Adiabatic Shear Banding and Its Transition to Fracture during High-Speed Blanking of 304 Stainless Steel Sheets

“…In addition, Winter et al [6] investigated ASB evolution in adiabatic blanking of 22MnB5 steel by conducting parametric analyses regarding clearance, blanking velocity, and impact energy. Both experiments and finite element (FE) simulations in LS-DYNA were carried out, revealing S-shaped ASB for clearance below 6.67% of sheet thickness and velocity greater than 7 m/s.…”

Local Temperature Development in the Fracture Zone during Uniaxial Tensile Testing at High Strain Rate: Experimental and Numerical Investigations

“…This is especially relevant when it comes to localization and a correspondingly strong increase in the local strain, strain rate, and temperature. An exemplary application where this effect becomes relevant is the formation of adiabatic shear bands in high-speed impact cutting [14]. The two effects of strain hardening and thermal softening superpose each other so that accurate and thermo-mechanically consistent material modeling is complicated significantly.…”