## 4 Conclusions  
In this paper, the microstructures and mechanical properties of an as-quenched NM450 TP wear-resistant steel were quantitatively investigated. The main conclusions are summarized as follows:  
XRD and SEM results indicate that the microstructures in the tested steel are only composed of ferrite and martensite, no residual austenite was found. The formed martensite and ferrite grains show directional features at the longitudinal cross-section of the plate due to a certain degree of deformation of prior austenite rolled in the temperature range of incompletely dynamic recrystallization.  
Based on EBSD analysis, the obvious inhomogeneous distribution of ferrite phase and martensite phase was discovered throughout the thickness of the steel plate. The content of ferrite on the two surfaces is more than that of ferrite at the core location. The highest content of ferrite on the top surface is found to be two times that of ferrite at the core location. Both the higher deformation storage energy and faster cooling rate at the two surfaces cause the austenite grains to start the phase transformation earlier and form more ferrite phases.  
The content of martensite and the deformation degree of prior austenite grains dominate the tensile properties, while the amounts of ferrite are not the main factor affecting the plasticity. Meanwhile, the steel plate exhibits obvious anisotropic effects of tensile properties in the steel plate. The tensile strengths along the rolling direction (RD) and along the transversal direction (TD) at typical locations are about 1500 MPa and 1600 MPa, respectively.  
The distribution inhomogeneity of the varieties of texture types exists throughout the thickness of the steel plate. The hard orientation [111] along the TD direction is stronger than that along the RD direction results in higher strength and lower plasticity along TD direction and lower strength and higher plasticity along RD direction. The higher contents of \(\alpha\)-fiber texture and near \(\gamma\)-fiber texture play a great role in the mechanical property.  
The inhomogeneity of microstructures and the anisotropic tensile property have an influence on subsequent processing and the practical implication. The bending process should consider anisotropic factors and avoid bending along the TD, while in the case of welding, the microstructure evolution in the heat-affected zone and mechanical property of the welding joints would be greatly affected by this inhomogeneous distribution of the dual phases. The results indicate that NM450 TP steel has some disadvantages in its microstructure and mechanical properties, although it has high strength and good formability. In order to improve its application, the effects of inhomogeneity microstructures on the bending mechanical property and microstructures evolution of welding joints should be addressed in future research.  
Conceptualization, G.L. and Z.Z.; methodology, G.L., S.L., J.R. and Z.Z.; writing--original draft preparation, G.L.; acquisition, analysis and interpretation, G.L., S.L., J.R. and Z.Z.; writing--review and editing, G.L. and Z.Z. All authors have read and agreed to the published version of the manuscript.  
This research was sponsored by the key scientific project of Hebei Iron and Steel Group Co., Ltd.; grant number HG2021221.  
Not applicable.  
The authors declare no conflict of interest.