Achieving an excellent balance of strength, plasticity, and stretch flangeability in a 1000 MPa grade TRIP-assisted bainitic ferrite steel
Year: 2024
Type: article
Abstract: To address the requirements for safety enhancement, weight reduction, and emission reduction, a novel transformation-induced plasticity-assisted bainitic ferrite (TBF) steel was processed by involving a pre-quenching (PQ) process. This steel was designed with varying PQ temperatures to achieve different fractions of intercritical ferrite and bainite , and its influence on mechanical properties of TBF steels was thoroughly investigated through tensile tests and hole expansion tests. The results demonstrated that the introduction of high-temperature PQ treatment before heat treatment can dramatically accelerate the formation of austenite during the secondary annealing process , thereby facilitating a more sufficient bainitic transformation in the subsequent isothermal process . With the increase of PQ temperature from 750 to 900 °C, abundant intercritical ferrite was replaced by lathy bainite . In comparison with conventional specimens, the high-temperature PQ treatment could reduce the fraction of intercritical ferrite and martensite-austenite (M-A) islands, in favor of delaying the initiation of microvoid and microcrack and improving local formability. In summary, the P-900 specimen exhibited optimal comprehensive mechanical properties, with the highest yield strength of 657 MPa, ultimate tensile strength of 1081 MPa, elongation of 28.7%, and hole expansion ratio of 35.1%.
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,430
OpenAlex ID: W4401609810