Liu Jiansheng

Study on Static Recrystallization Softening Behavior of 316LN Steel

In this paper, The experiments were carried out in Gleeble 1500D thermo-mechanical simulator by double-pass hot compression method. Offset method(0.2%) was used to determine the softening. The static recrystallization softening behavior of 316LN steel under different deformation conditions was studied and static recrystallization kinetics model was established. Deformation temperature is 900¿ -1050¿; strain is from 0.1 to 0.3;initial grain size is 75μm and 170μm; strain rate is 0.1s-1. The experimental results show that deformation temperature and strain and initial grain size are important factors which affect static recrystallization softening. The higher deformation temperature is, the larger strain is, the smaller initial grain size is, the larger static recrystallization softening is. Based on experimental results, the static recrystallization kinetics model of 316LN steel is proposed with the activation energy of 353.253 kJ/mol. These results provide a reference for theoretical development of static recrystallization and actual production of 316LN steel.

Experiment Research and Finite Element Analysis of 30Cr2Ni4MoV Steel Porosity Consolidating

In this paper, distribution and pattern of the microcosmic porosity in 30Cr2Ni4MoV steel were researched quantificationally by metallographic analysis. Initial relative density of the defect zone was calculated. Porosity model was used to simulate the FM stretching with process parameter as 1200¿ temperature, 0.6 die width ratio by finite element software deform-3d. Variational pattern of the relative density was obtained during FM stretching. The result showed the friction factor has effect on porosity consolidating at the prophase of deforming mostly, and when the double-faced reduction ration is 20%, initial porosity can be consolidated after 3 passes deforming at least. By the 2MN oil hydraulic press, the same scaled stretching process was finished. Metallographic analysis data and mechanical property were used to reflect the porosity consolidating at different deforming stage. The experiments were in better agreement with numerical simulation, which verified the feasibility of finite element analysis and provided an important reference for virtual production.