压力容器钢板分层缺陷检测及处理

分析了压力容器钢板分层缺陷，针对压力容器制造和定期检验提出了相应的检测和处理方法。     

谈对进口二手压力容器的检验

本文针对进口二手压力容器的特点及检验实际，提出了对其进行检验和评定的标准及选用原则。近来有些新建的石油、化工单位从国外进口了一些二手压力容器，准备在新建厂中使用。如何保证一个容器在今后使用中，有足够的安全性和寿命，本文就针对进口二手压力容器的特点及检验实际，探讨如何做好其检验和评定工作。     

The results of a round-robin exercise on pressure vessel defect assessment

A full scale fatigue test on a 3·66-m diameter, 25-mm wall thickness, 11·38-m-long pressure vessel containing defective welds has been carried out by British Gas.

The prime intention of the test was to demonstrate the ability, or otherwise, of a grossly defective pressure vessel to withstand large cyclic and static loads. However, the test also provided a good vehicle for evaluating defect assessment methods.

The Department of Trade and Industry awarded British Gas a grant under the Department's Support for Innovation for the above pressure vessel test. This grant was used to organise a ‘round-robin’ exercise in which five organisations conducted fatigue assessments on defects in the vessel. This round-robin and a report on the vessel test, are presented in this paper.

The major conclusion of the ‘round-robin’ exercise was that the analysis of pressure vessel defects requires a high degree of skill and judgement and there is a need for a documented, generally accepted, pressure vessel defect assessment procedure.     

压力容器补强圈与筒体间接触特性的应力分析研究

本文采用有限元分析方法对接管补强圈和筒体的不同接触状态进行了应力分析,揭示了不同接触间隙下的接触应力分布的情况。计算结果表明,随着压力的加载,接触位置由内外焊缝中间逐步扩散到整个接触面,接触间隙与接触应力值呈正相关。     

Analysis of biaxial loading effect on fracture toughness of reactor pressure vessel steels

The local stress–strain state (SSS) near the crack tip and its connection with the crack tip opening displacement and J-integral under biaxial loading have been studied by finite element methods in elastic–plastic finite strain statement. Numerical investigations have been performed for various crack lengths and two types of biaxial loading (tension and bending) under conditions of small- and large-scale yielding. To predict the biaxial loading effect on cleavage fracture toughness, the procedure has been elaborated, this being based on the revealed regularities for SSS near the crack tip under biaxial loading and brittle fracture criterion proposed earlier. Prediction of the biaxial loading effect on cleavage fracture toughness has been performed as applied to reactor pressure vessel steel. The calculated results have been compared with available experimental data. Alternative approaches for prediction of the biaxial loading effect on fracture toughness have been discussed.     

Sensitivity analysis in shape optimization design for a pressure vessel

This paper discusses the sensitivity analysis for a finite element model during shape optimization design for a pressure vessel. The derivative of a stiffness matrix and various load rankings with respect to design variables are obtained. Because the information resulting from the finite element analysis is fully utilized in this method, the programs are greatly simplified so that it becomes possible to carry out the shape optimization with comparatively more variables. The conclusion is illustrated by an example.     

压力容器的腐蚀案例分析及防腐措施

压力容器是目前常见的承压设备,根据压力容器的定义、压力容器的特点以及使用情况本文介绍了压力容器的三种腐蚀原因:物理腐蚀、化学腐蚀和电化学腐蚀。例举了现实检验中遇到的化学腐蚀和电化学腐蚀案例,对案例进行了原因分析并根据分析的结果提出了几点防腐措施。最后介绍了现在最常用的几种防腐措施。     

Adequacy of estimates and variability of fracture-related properties for reactor pressure vessel materials

It is sometimes necessary to estimate K_Ic, NDTT, or RT_NDT based on other types of test data because actual toughness results are not available. Correlations used to estimate these toughness parameters are often based on minimal Charpy V-notch data. This paper evaluates the adequacy of correlating Charpy V-notch data with fracture toughness parameters for two pressure vessel materials and weldments. Statistically based correlations or ‘engineering judgments’ were used to establish a conservative prediction criterion.     

Failure probability and optimum microstructure of pressure vessel steels

This paper presents a method for assessing the probability of brittle fracture in steels used for nuclear power generating equipment. The method is based on a statistical analysis of microstructural parameters and on physical models of the initiation and propagation of cleavage microcracks. The least probability of brittle failure ascertained by this method has been utilized for determining the optimum ferrite grain size. This method represents a foundation for systematic control of the brittle fracture characteristics of engineering steels employed for the components of nuclear power stations.     

Hydrogen embrittlement of CrMo and CrMoV pressure vessel steels

The variation of $\text{K}{}_{\mathrm{i}}$ with time to fracture and the threshold values of $\text{K}{}_{\mathrm{ISH}}$ in an hydrogen environment were measured for four CrMo and CrMoV pressure vessel steels in various conditions of heat treatment. The CrMoV grades displayed higher $\text{K}{}_{\mathrm{ISH}}$ thresholds, suggesting that they are less susceptible to hydrogen embrittlement than CrMo grades of comparable strength. The findings were analysed with regard to the concurrent presence of various alloying elements and their effects on the microsegregation of detrimental impurity elements at the austenitic grain boundaries, where these harmful elements can, in conjunction with hydrogen, cause intercrystalline embrittlement. Studies were also made of the kinetics of stable crack growth in these materials.