硫化物应力腐蚀开裂试验应力环载荷的测量及标定

硫化物应力腐蚀开裂试验的常用载荷测量方法是通过测量应力环的变形量计算载荷。指出了该方法在标定和测量过程中容易产生较大误差的原因。通过测量对比,证明了采用载荷传感器直接测量载荷的方法可减小误差,更适合作为试验过程中的载荷标定方法。     

KMT遥测系统在风机主轴载荷测试中的应用

在风力发电机组实际运行中,叶轮捕获的自然风所获得的动能传递到机组传动链上,动能传递的大小和剧烈程度直接关系到风机的性能和寿命。为直观、精确掌握相关数据,需采用一种合适的方式才能准确获得。本文在实践基础上系统介绍德国KMT公司MT32型遥测系列设备如何测试主轴扭矩和弯矩。     

虚拟仪器测试技术在爆炸应力波测试中的应用

爆炸应力波的分析研究对矿山工程有重要的指导作用。采用基于LabVIEW和采集卡的虚拟仪器测试技术,对矿山爆破非均质不连续岩体中爆炸应力波进行现场测试,取得了测试数据,并和理论计算值进行了对比分析。     

铝合金应力腐蚀的电化学研究

应用电化学测试法、恒载荷拉伸法和慢应变速率拉伸法研究了硬铝合金LY12 3.5 %NaCl溶液应力腐蚀体系的电化学特性。结果表明应变速率比应力对电化学特性的影响更大。应变速率为 1.13× 10 - 5/s时 ,应力腐蚀较为敏感 ;形变强化阶段力学、化学效应最为明显 ;LY12的应力腐蚀开裂是阳极溶解和氢脆共同作用的结果     

应力腐蚀试验机数据处理系统

本文介绍了ＧＹＦ－３０低应变速率腐蚀试验机数据处理系统的原理及系统设计。     

地铁屏蔽门风压载荷测试

通过地铁屏蔽门风压载荷和人群挤压载荷的测试,对屏蔽门系统单元进行受力分析,检测屏蔽门系统的结构的可行性,确保地铁屏蔽门系统的安全性,给乘客出行乘车安全保障。     

腐蚀疲劳试验系统的开发及应用

海洋工程用钢服役时一直受到环境腐蚀和疲劳载荷的耦合作用,而传统的腐蚀、疲劳单项评估已不能满足检测需求,因此开发了一套腐蚀疲劳试验系统来测试材料在腐蚀环境下的疲劳寿命,并使用该系统对海洋工程用S690QL高强钢板在腐蚀环境下的疲劳寿命进行了测试.结果表明:该系统可以对试验温度、流速、腐蚀介质pH值等参数精准控制,并可以实...     

LabVIEW软件在胶印机振动测试系统中的应用

胶印机产生的振动严重影响印品质量,通过胶印机振动测试系统的测试可以了解胶印机的振动情况,分析认识有害振动的来源,从而想办法消除其影响,对提高印品质量有重要意义.本文主要介绍了LabVIEW软件在胶印机振动测试系统中的应用,并最终使用LabVIEW编写的程序来分析实测的振动信号.     

管线钢的应力腐蚀研究现状及损伤机理

回顾了管线钢的应力腐蚀研究现状,并比较了发生在管道外的“经典型”的高pH应力腐蚀开裂与近十多年来发现和研究的近中性pH应力腐蚀开裂的特征,讨论了它们的影响因素以及开裂机理,最后展望了埋地管道的未来研究方向。     

基于灰色理论的高强铝合金应力腐蚀开裂预测模型的建立与应用

采用3.5%NaC1溶液中预制裂纹的方法测试了2124高强铝合金的应力腐蚀裂纹扩展长度随时间的变化,获得了裂纹扩展速率随腐蚀时间的变换规律及应力腐蚀断裂韧性界限值,并对断口进行分析.根据裂纹扩展的基本规律,运用灰色理论GM(1,1)模型,依据2124铝合金应力腐蚀开裂裂纹扩展长度的原始数据进行了灰色预测,并对预测结果进...     

Investigation of stress corrosion cracking behavior of super 13Cr tubing by full-scale tubular goods corrosion test system

In this paper, a self-built device called “full-scale tubular goods corrosion test system” was used to test a 6 m length super 13Cr tubing (with coupling) to study its corrosion performance in spent acid. The specimen fractured at the tubing and was investigated by visual inspection, optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and mechanical test. It was the joint function of tensile force (78.6% actual yield strength), inner pressure (70 Mpa) and spent acid that induced stress corrosion cracking (SCC) of the tubing at 120 °C. Three different areas were found on the fracture surface, including crack initiation area, crack expansion area, and final fracture area. The fracture initiated from the “X” shape corrosion cracks which were evolved from small corrosion pits. The reduction of ductility and toughness may also facilitate SCC of the tubing.     

振动时效技术及残余应力测试

对残余应力的形成原因、消除技术及测试技术做了详细论述,并给出一种振动时效及残余应力测试实例,对相关工程技术人员具有重要的参考价值。     

Assessment of stress corrosion cracking susceptibility by a small punch test

The object of this study is to establish a new test method for evaluating stress corrosion cracking (SCC) susceptibility of high-strength steel using a small punch (SP) test and acoustic emission (AE). A miniaturized specimen (10 × 10 × 0.5 mm) is adopted for SCC evaluation. The experiments are conducted at various loading rates and at various orientations of the specimen. The cumulative average amplitude of the AE signal per unit equivalent fracture strain ( ε _qf ) increases as the SCC susceptibility increases. Through the load–displacement behaviour, the fracture energy ( E _SP ), the SEM fractographs, and the correlation between the SCC susceptibility and the AE characteristics, it is proved that the small punch test method combined with AE measurements is a useful method to evaluate the SCC susceptibility of high-strength steel.     

周浸腐蚀试验箱智能控制系统

针对周浸腐蚀试验箱工作环境复杂,温度和湿度难于控制等问题。设计一种用于在实验过程中自动调节温湿度的周浸腐蚀试验箱智能控制系统,该系统包括温度专家控制器和湿度模糊控制器。由于试验箱封闭,温度的变化会影响湿度,所以系统中还采用解耦控制策略。实际运行结果表明该系统工作可靠,且温湿度控制精度高。     

Strain-driven corrosion crack growth: A pilot study of intergranular stress corrosion cracking

This work proposes a model for corrosion driven crack growth. The model poses a moving boundary problem, where a chemical attack removes material from the body. The rate of the chemical attack is a function of the strain along the body surface. No crack growth criterion is needed for the analysis. A finite strain formulation is used and the material model is assumed hyperelastic. The problem is stated for a large body, containing a large crack. A low frequency cyclic loading is considered. Thus, corrosion is assumed to dissolve material with a rate approximately proportional to the strain rate. The problem is solved using finite element method based program, enhanced with a procedure handling the moving boundary. Parametric studies are performed for a series of different initial shapes of the near-tip region. Presented results show that the crack growth rate is largely dependent on the initial crack geometry. For a set of initial shapes and load levels steady-state conditions of growth are achieved, while for the others the cracks show tendency to branch.     

The control of catalytic poisoning and stress corrosion cracking

When a structural metal is stressed in a hydrogen environment, the metal may crack at stress levels much lower than its normal strength. This embrittlement is caused by hydrogen atoms or ions rather than hydrogen molecules. The catalytic dissociation of hydrogen molecules into atoms or ions takes place at dislocation sites on a metal surface. The termini of dislocations on a metal surface are sites of localized high energy. There are “poisons” which will retard or even stop catalytic processes. The toxicity of a poison depends on the binding energy of the foreign atom to a dislocation terminus.Cracked specimens made of 4340 steel were tested in hydrogen gas and its mixture with SO₂, CS₂, CO₂, N₂ and Ar. Both SO₂ and CS₂ are very “toxic” and can stop a running crack. The toxicity of CO₂ is moderate. n₂ and Ar have no noticeable effect on a running crack.