Comparison of Flow Behaviors at High Temperature of Two Press Hardening Boron Steels with Different Hardenability

Abstract

The deformation behavior and the constitutive description of materials are important in the design and numerical simulation of manufacturing processes. In this work, the rheological behavior of two quenchable boron steels was derived in the range of interest for the Press Hardening (PH) process. For this study, the following steps were performed: (i) Design of the specimen geometry adopted during the hot tensile tests in the Gleeble®3180 physical simulator. (ii) Performance of hot tensile tests at temperatures between 750 and 850 °C and strain rates of 0.01–1 s−1. (iii) The description of the material constitutive model by means of the Arrhenius-type equation and the comparison between the experimental and predicted data. Firstly, the method was validated on USIBOR®1500 boron steel by means of a comparison with existing literature data, and good agreement with other scientific works was found. Finally, this method was also adopted on USIBOR®2000, a steel that belongs to the new generation of Ultra-High-Strength Steels (UHSS). A comparison between the rheological behavior of these two steels was carried out. The results show that USIBOR®2000 steel exhibits greater strength compared to USIBOR®1500 steel. The Arrhenius constitutive model well predicts the flow behavior of both steels.

Analysis of Transition Zone on a Hot‐Stamped Part with Tailored Tool Tempering Approach by Numerical and Physical Simulation

“…The specimens adopted during the physical simulation tests were tapered in the central section to reproduce the stamping and quenching phases in the die characterized by a high cooling rate. Palmieri et al [ 27–29 ] demonstrated that the reduction in the width and length of the central specimen zone leads to an increase in the cooling rate.…”

Effects of the Intermediate Precooling Parameters on the Mechanical Properties of a Tailored Press‐Hardened Component in Advanced High‐Strength Steel

“…This geometry, combined with compressed air released from nozzles present in the Gleeble system test chamber, ensured the replication of the quenching phase characterized by a cooling rate of about 10 2 K s À1 . [23,39] Figure 7a highlights that three K-type thermocouples were welded onto the face specimen, one of them was welded in the specimen center and the other two at about 5 and 15 mm from the center. The Gleeble physical simulator adopted for these tests heats the specimens by exploiting the Joule effect and it was equipped with a proportional-integralderivative (PID) controller that compared the temperature measured by the central thermocouple (pilot thermocouple) with the desired temperature and adjusted the current density accordingly.…”

Effect of heat treatment on microstructure and properties of 10B21 cold-heading steel for fasteners

“…At 200 °C tempering, because of the carbon atoms image dislocation segregation and eliminating part of the internal stress, so the plasticity gradually increased. The slatted martensite got good toughness, mainly due to the presence of participating austenite between the slats, although its amount is small, its role cannot be ignored [18].…”