When mastering, producing and applying such new materials, especially under the condition of mass continuous production, the main obstacle encountered is the lack of regular research on the hot forging processing parameters and the recrystallization law of deformed austenite during cooling after hot deformation, as well as the continuous cooling transformation behavior, resulting in the lack of evidence for the control of the hot deformation parameters of the workpiece and the subsequent cooling process, which brings difficulties to the design of the controllable cooling production line and ensuring the stability of the workpiece performance, It limits its application in mass production. Therefore, the work to be continued should mainly focus on the following three aspects:

1) The mechanical properties of microalloyed non quenched and tempered steel connecting rod are not only affected by the chemical composition and metallurgical factors of the material, but also the preparation technology and process (such as controlled rolling / controlled cooling and controlled forging / controlled cooling) have an important impact on its strength and toughness. In order to meet the strength and toughness requirements of specific parts, for example, through the adjustment of composition and forging process, the microstructure and mechanical properties of the steel are correspondingly changed to stabilize the quality of connecting rod.

2) The computer simulation calculation technology provides a new effective tool for the application and development, composition design and process parameter selection of non quenched and tempered steel connecting rod, so that the strength and toughness of the material can be predicted and controlled.

3) The microstructure of microalloyed non quenched and tempered steel connecting rod was analyzed by optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM), the relationship between microstructure and properties was obtained, and the strengthening phase of microalloyed non quenched and tempered steel connecting rod was discussed and analyzed. The fracture surfaces of microalloyed non quenched and tempered steel connecting rod were analyzed by SEM and EDS. The effects of different forging process parameters on the microstructure and properties of non quenched and tempered steel connecting rod were studied. The forging process parameters include forging heating temperature, final forging temperature, cooling rate after forging, secondary heating temperature, etc. the practicability of using non quenched and tempered steel connecting rod without quenching and tempering treatment to replace quenched and tempered steel connecting rod is discussed.