An Investigation Of The Trimming Of Boron Nitride Steel (22mnb5) During The Die-Quenching Process

The in-die hot trimming cuts the heated blanks during the phase transformation from an austenite phase to a martensite one. This process could reduce the total cycle time of the hot stamping process and enhance the tool life. The aim of the present work is to identify key parameters of the in-die hot trimming, and therefore to secure the control chart for the sound surface-quality and the low die-wear in the blanking process of boron steels. The numerous experiments were carried out while varying the temperature of boron steel and the clearance between the punch and die. The pyrometer mounted on the blanking tool could measure directly the actual temperature of the boron steel located at the trimming site during the rapid cooling. Profiles, percentage of depth ratios, hardness, and microstructure of sheared zones are measured to characterize the influence of process parameters. From our investigation, the trimmed zone which has a desired surface quality and dimensional accuracy could be achieved in the temperature range from 500 to 550 degrees C and below the clearance of 5%. (C) 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the International Conference on the Technology of Plasticity.