Experimental Research On Material Properties Of Pressure Vessels Under Special Conditions

As the development of industry technology, application of pressure vessels has penetrated into various fields, more and more pressure vessels operate in ultra high pressure, cryogenic, external pressure, corrosion and other relatively special conditions, such as ultra high pressure reactor used forartificial crystal, cryogenic vessel used for natural gas exploitation and storage, vacuum containers used for condensation and crystallization, acetic acid equipment and so on. Special requirements are needed for thesepressure vessels regarding the structure,materials, design and manufacture.However, few basic researches on these special containers areperformed in China and as a result, we have to refer to the data from other foreign countries for the design and manufacture of these vessels. Specifically, the data of material properties is extremely rare, which not only hindersthe development of the national standards but also restricts the development of the related industries.This research wascarried out under the support of quality inspection of public scientific research projects "Research on key technology and standard of the ultrahigh pressure vessel"(No.201210242), "Research on the designing curves of external pressure vessel materials"(No.201110033), "Research on the key technology of test and evaluation of low temperature performance of austenitic stainless steel"(No.201010028).The purpose is to perform extensive material experiments to provide the basic material datafor the design of special pressure vesselssuch as ultrahigh pressure (the design pressure is more than 100MPa), external pressure, cryogenic temperature and corrosionin order to ensure the safety of the pressure vessels in China. The main work and achievements are as follows:(1) For ultra high pressure vesselswith the design pressure more than 100MPa, the basic mechanics properties of high strength steels commonly used in China were experimental studied. Based on the test data, the basic performance requirements of the material for ultra high pressure vessels were proposed. Both the yield and tensile strength reduction coefficients of the material were obtained, which formed the basis for determining the minimum material guarantee value of yield and tensile strength at different temperatures. The shear stress and strain relation of the material is obtained by torsion tests, which provides the basic data for calculating the blasting pressure. Material fatigue properties were obtained through material fatigue tests, and the fatigue design curves of the material used for ultrahigh pressure vesselswere drawn based on the fatigue testing data.(2) For the external pressure vessels, in addition to strength calculation, stability checking is also necessary. Graph algorithm is widely used for the design of external pressure vessels in China, but unfortunately the material data of these graphs come from ASME standard which are not well consistent with China's material performance. By performing tests of materials commonly used in China to construct the external pressure vessels,the testing anddrawing method for exteral pressure curveswere summarized and the external pressure curve graphs for typical materials were completed which have the proprietary intellectual property right and proved to be the unique contributions to the design of external pressure vessels in China.(3) For cryogenic pressure vessels with the design temperature below-40?,both austenitic stainless steel S30403 and S31608 were tested after performing different levels of strain-hardening and the data of yield strength and tensile strength were measured. The variation relationship of yield strength and tensile strength after strain-hardening was analyzed and the law between yield strength and pre-deformation was obtained. Charpy V impact tests of austenitic stainless steel S30403 were carried out at room temperature,-196? and -269? to measure impact energy, lateral expansion and crystalline section rate. Impact properties of austenitic stainless steel S30403 were analyzed to study toughness at low temperature.(4) For the domestic used zirconiumplate and the welding test plate with different thickness and heat treatment, mechanical properties at room temperature and high temperature, chemical composition, metallographicstructure, corrosion resistance were studied. These properties were analyzed and compared with the performance of the corresponding zirconium plate products imported in order to provide the test data support for the domestic zirconium plate instead of the imported products.Part results of this research have been adopted by the relevant national standards,such as GB150-2011 " Pressure vessel" and the draft of "Ultra-high pressure vessel".