Advance in Cu precipitation during aging treatment of Cu-bearing low-alloy high-strength steel

Cu-bearing low-alloy steel is a kind of important low-carbon low-alloy high-strength steel. It has excellent comprehensive application value by making up for the strength reduction of low-carbon equivalent through Cu precipitation, taking into account high strength, good welding performance, low temperature toughness and corrosion resistance. The research progress of Cu precipitation in Cu-bearing low-alloy steel at home and abroad is reviewed. Taking the hardness change curve of Cu-bearing low-alloy steel during aging treatment as an example, the change trends of mechanical properties for materials are clarified, and the strength increment formula corresponding to Cu precipitation based on precipitation strengthening mechanism is summarized. The evolution process of Cu precipitation during aging treatment is sorted out, including phase transformation, crystal structure transformation and mathematical model related to the size of Cu precipitated phase. The common added alloying elements in Cu-bearing low-alloy steel and the effect of alloying elements on Cu-bearing low-alloy are summarized. Finally, the development for new generation of Cu-bearing low-alloy steel is prospected. It is pointed out that regulating the size and distribution of Cu precipitation by optimizing the theoretical model and adding Ni-based alloying elements is an important means to prepare Cu-bearing low-alloy steel with better performance.