Application of rough set method to the weightings of high temperature creep factors of boiler water wall

Abstract

At the high temperature state or the applied stress is less than the yield strength, general metal itself will generate slow plastic deformation until fracture, which is called creep rupture. Under room temperature, general alloy will have creep phenomenon, but it is not obvious. However, under high temperature environment, the creep rupture becomes very important. It is not only very important to predict the components' life, but to assess the remaining life of the equipment components during the operation to applications. Hence, it becomes hot topic in recent years. In the past, we always use the anti-creep steel generated from experiments to extend the creep deformation data of steel life plans, and is called stress and strain. But it needs substantial funds and time to obtain the data, so, it is limited to the direct analysis of the small data. Based on this, the paper uses the significant in rough set to find the each weighting of influence factor on creep life. Through different discrete methods, we found that the factor of strain is more important than stress, the results are not only in line with the traditional regression results, but they are also corresponding to the actual situation.