Microstructure Development and Mechanical Properties of a Hot Stamped Low-Carbon Advanced High Strength Steel Treated by a Novel Dynamic Carbon Partitioning Process

Abstract

To make steel exhibit attractive properties as high strength and good ductility, this paper presents a novel one step method for forming-Q&P integration—Hot Stamping-Dynamic Partitioning (HS-DP) process. The proposed HS-DP process is simulated with salt bath heat treatment. The effect of microstructure and mechanical properties in a low-carbon AHSS with different cooling rate of the new process is investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile test methods. Microstructure of the steel subjected to HS-DP treatment is mainly composed of initial quenched martensite phase , final quenched martensite phase and retained austenite phase formed. The impact of retained austenite is also discussed, especially the influence of elongation caused by various retained austenite volume fraction and carbon-content. This experiment illustrates the promising application potential of the hot stamping-dynamic carbon partitioning process.

Microstructure and mechanical properties of a hot pressing-dynamic partition treated steel

“…The chemical composition of the HP-DP steel studied in this work is Fe-0.19C-1.55Si-1.53Mn-0.95Ni-1.01Cr-0.45Mo-1.01Cu-0.033Ti-0.0027B-0.025Al (wt-%) as reported in [7,9,10]. The steel was melted in a vacuum furnace, hot forged to a slab of 60 mm thickness and hot rolled to the blank of 4 mm thickness.…”

“…Following this, the authors of this paper proposed the integrated hot pressing and dynamic partition (HP-DP) process [9,10]. The feasibility of the process was proved by physical simulations and high PSE level up to 25,600 MPa% with a tensile strength of 1600 MPa and an elongation of 16% could be achieved in the developed low-carbon press-hardened steels.…”

A new integration of hot pressing and carbon partition process to produce high strength steel components with better toughness

“…Then the authors proposed the HP-DP process [15], for which the temperature-time profile can be shown in Fig. 1. …”