1. The "one-step" quenching and partitioning (Q&P) process combined with the annealing process was applied to medium-Mn steel to study the effects of different annealing temperatures on the microstructure, C-element diffusion and mechanical properties.
2. The martensite-austenite island of the test steel gradually decreased or disappeared, the polygonal blocky ferrite increased, and the large lath-like retained austenite became flake-like (film-like).
3. Excellent comprehensive mechanical properties were obtained for the test steel annealed at 670°C with "one-step" Q&P process, with an ultimate tensile strength of 1130 MPa and total elongation of 26.80%.
The article is generally reliable and trustworthy as it provides a detailed description of the experimental procedure used in studying the effects of different annealing temperatures on medium-Mn steel. The results are presented in a clear manner and supported by relevant data. However, there are some potential biases that should be noted. For instance, there is no mention of any possible risks associated with using this method or any other methods that could be used instead. Additionally, there is no discussion about unexplored counterarguments or alternative points of view which could have been explored further. Furthermore, there is a lack of evidence for some claims made in the article such as how C can be taken full advantage by retained austenite due to its relatively small amount in the test steel. Finally, it should also be noted that while this article presents one side of the argument fairly well, it does not present both sides equally which could lead to partiality in its conclusions.