The Effect Of Impurity Elements Antimony On The Creep Behavior Of 2.25Cr1Mo Heat-Resistant Steel

2.25Cr1 Mo is a commonly used pressure vessel steel,its application is very extensive.Under normal circumstances,its use temperature is between 450 ?-600 ?.Due to prolonged service in such a complex environment,the failure of most high temperature environmental carrying members is caused by the high temperature creep caused by high temperature and high pressure,which in turn causes significant damage to people's life and property.In the steel refining process,there will be inevitably some impurities that influence the performance of steel,such as Sb,P,Sn,As and so on.These impurity elements will have a great impact on the performance of steel,especially its high temperature creep performance.On the current research status,the study of the specific impact on a particular element is still relatively small.Sb elements almost have a certain content in all the heat-resistant steel,but almost no related study of its impact on the creep of steel is reported.In this context,it is very important to do research in this area.It is hoped that through the concrete analysis and research,the mechanism of Sb element on the high temperature creep performance of 2.25Cr1 Mo steel will be systematically analyzed.Analyze the extent of the impact of the elements,and then provide a reference to the practical application of steel standards.In this paper,a series of high temperature creep experiments are conducted on 2.25Cr1 Mo steels undoped and doped with impurity element tin.Based on the analysis of the creep test results,the creep equation was established to compare the di fferences in the high temperature creep properties of the two materials,And the various characterization methods were used to analyze the effect of the impurity element Sb on this difference and to further analyze the reason.After austenitizing at 980 ?,the materials have the same grain sizes,and then the materials after quenching,tempering and aging treatment process into a standard sample.At the temperature of 500 ?,550 ? and 600 ?,a series of high temperature creep contrast experiments were carried out with different stress.The creep equation was established according to the experimental data,and the performance difference was analyzed.The results show that the impurity element Sb reduces the critical stress value of 2.25Cr1 Mo steel,it has little effect on the creep stress index.In general,the creep damage tolerance of pure steel is high,and the creep life of the steel with the impurity element Sb is greatly reduced.Grain boundary composition analysis shows that the impurity element Sb is segrega ted at the grain boundary,which reduces the grain boundary energy of the grain boundary,so that under the same experimental conditions,the material is more likely to produce tissue degradation,and provide more creep cavities nucleation point,the resul t of the macro is the high temperature creep performance of the material decreased significantly.