Study On Thermal Deformation And Damage Behavior Of Inclusion Materials

Large forgings are the core components of large equipment. Various industries improve their requirement for the usability of products continuously and the forming process of products is becoming more and more complicated. The requirement of core part for the usability of products depends on the cleanliness of raw materials and the level of non-metallic inclusions in steel is one of the important indexes to evaluate the steel cleanliness standard. The production process of large steel ingot determines the existence of non-metallic inclusions in the forgings inevitably. The existence of the inclusions in steel can influence the mechanical properties, production and usability of forgings seriously. Therefore, it has great significance to explore the effects of inclusions in the steel on the deformation behavior of substrate material. 2.25Cr-1Mo-0.25 V steel containing inclusion was taken as the research object in this paper. The combination of physical experiment and numerical simulation method was adopted to study the deformation and damage behavior of materials containing inclusions and the evolution and forming process of the inclusion crack was reappeared.First of all, metallographic microscope and scanning electron microscopy(SEM) were adopted to analyze the existence state and the size distribution of inclusions in the material and the morphology, existence position and status of the inclusions were obtained. Then Gleeble-1500 D thermal simulated test machine was used to conduct the extension experiment at elevated temperature and the deformation process curves of 2.25Cr-1Mo-0.25 V steel at different temperature were obtained.Based on the basic experiment, software ABAQUS was used to study the deformation and damage behavior of materials containing inclusions. Through the establishment of body cell model containing inclusions and the use of metal ductile damage criterion, the effect of the existence of inclusions on the distribution of the matrix stress and strain was analyzed under the microstructure and the the evolution and forming process of the inclusion crack was reappeared. Through the analysis of macro mesoscopic coupling, the critical strain values of the damage initiation, crack and the formation of macroscopic crack at the temperatures of 850℃,950℃,1050℃,1150℃,1250℃ and at the strain rates of 0.001S-1,0.005S-1 were determined. And through the hot compression experiment of the material containing damage, the applicability of the parameter was verified. The results can provide reference for engineering practice.