Metal Material Of High-temperature Creep Characteristics Research

In the petrochemical, metallurgy, machinery and other industries, a large number of metal components under the conditions of high temperature, high pressure, strong corrosive, once these bearing member accidental damage will lead to disastrous consequences and cause huge economic losses. Therefore, the safety and reliability of the equipment must be put forward higher requirements. And long-term high temperature, high pressure, these bearing member will face a special challenge—high-temperature creep. For example, for the stainless steel pipe long-term work under high-temperature, high pressure, creep behavior determines the life of the pipeline and its safety and reliability.But due to the organization, chemical composition and thermal physical properties between the metal materials there are larger differences, so different kinds have different creep properties of steel. For example, between the creep performance of low alloy steel and stainless steel is a big difference. So the study of material high temperature creep property is particularly important.At present, the creep characteristics of creep test study and finite element numerical analysis of two. The most commonly used test method is the uniaxial creep tensile test. But because of its limitations, researchers also proposed "Cryo-Cracking" method, micro sample technology, a new method to solve the uniaxial tensile creep tensile testing supplies, demanding specimen preparation, but still time-consuming. In comparison, the finite element analysis is not only low-cost, short-consuming, high precision, and has a solid theoretical foundation. Therefore, I use the commonly used steel of high strength low alloy steel Q345R and austenitic stainless steel304two chemical industry as the research object, through the finite element analysis software to simulate the high temperature creep properties of them. The specific contents are as follows:1. The use of metal materials viscoelastic mechanical analysis of high-temperature creep of both steel and its components. Get the viscoelastic constitutive equations of the two kinds of metal materials and its components2. Through the finite element model of the two materials, obtained the creep strain-time curve of the two materials after loading and solving, Compared with the experimental data to verify the reliability of the numerical simulation method. And gets the Q345R steel and304stainless steel in simulated under a certain temperature after10000h generate creep limit of0.2%of the total strain.3. Simulate the creep characteristics of Q345R perforated sheet and304stainless steel pipe. Analysis of Q345R perforated sheet under the200MPa, after200h,400h,600h, the creep strain contours can be seen that, stress concentration effect on the creep properties of the specimens is great, can make the hole around creep degree than other parts; From under450℃,600℃, the displacement nephogram of304steel tubes can be seen, the inner surface of the steel tube is the most serious part of the creep, creep decreases the influence of outward along the radius;304stainless steel tube under450℃, after10000h when produce1%of the total strain of creep limit to4.85MPa;600℃, after10000h when produce1%of the total strain of creep limit to3.78MPa.Through the above research results, in order to provide a theoretical basis of correctly predict the axial stress state of high temperature components creep properties, to evaluate the safety and economy of high temperature components has very important application value.