**7. Conclusions**

High-alloyed steels are complex alloys, along with desired chemical composition and multiple phased microstructures through various heat treatment processes. Various strengthening mechanisms through controlled heat treatment techniques are adopted to achieve excellent mechanical properties. The chapter examines the advanced methods used in the field of heat treatment routes for high-alloyed steel and focuses on their structure-property relation. The high-alloy steels acquire its enhanced mechanical properties from the modified microstructures of austenite, ferrite, martensite, and some carbides. Ferrite and austenite provide the formability, whereas martensite provides strength to the steel in addition to the low-temperature transforming phases like bainite and retained austenite to achieve better combinations of mechanical properties. The advanced thermomechanical treatments used for high-alloy steels aim to explore the possible phases that contribute to the mechanical properties. In thermomechanical routes aims on heat treatment as the microstructural qualities required for the steels are mainly achieved by post-deformation controlled heat treatment processes. From the above discussions, it can be concluded that the microstructure and its properties are based on variation in chemical composition and processing conditions. Determined by latest demands for the performance of the high-alloy steel in various applications, the progress of thermomechanical processing is introduced.
