Metallurgical special features of the production of welded joints in dispersion‐filled metallic composite materials

Investigations were carried out on the special features of the structure and properties of electron beam welding joints in 150 mm thick plates of pearlitic steel 16GNMA and 160 mm plates of 12Kh2MFA steel. It is shown that using vacuum as the shielding medium results in the efficient removal of gases from the weld pool and reduces the content of alloying elements with high vapour tension.     

Strain-induced martensitic transformation in stainless steels: A three-dimensional phase-field study

A three-dimensional elastoplastic phase-field model is developed to study the microstructure evolution during strain-induced martensitic transformation in stainless steels under different stress states. The model also incorporates linear isotropic strain hardening. The input simulation data is acquired from different sources, such as CALPHAD, ab initio calculations and experimental measurements. The results indicate that certain stress states, namely uniaxial tensile, biaxial compressive and shear strain loadings, lead to single variant formation in the entire grain, whereas others, such as uniaxial compressive, biaxial tensile and triaxial strain loadings, lead to multivariant microstructure formation. The effects of stress states, strain rate as well as temperature on the mechanical behavior of steels are also studied. The material exhibits different yield stresses and hardening behavior under different stress states. The equivalent stress is higher at low strain rate, whereas a higher elongation is obtained at high strain rate. The deformation temperature mainly affects the hardening behavior of the material as well as the transformation, i.e. martensite volume fraction decreases with increasing temperature. Some of the typical characteristics of strain-induced martensite, such as the formation of thin elongated martensite laths, shear band formation and nucleation of martensite in highly plasticized areas, as well as at shear band intersections, are also observed.     

Automatic Train Operation Using Autonomic Prediction of Train Runs

In this paper, we present an automatic train control method adaptable to disturbed train traffic conditions. The proposed method presumes transmission of detected time of a home track clearance to trains approaching the station by employing equipment of Digital ATC (Automatic Train Control). Using the information, each train controls its acceleration by a method that consists of two approaches. First, by setting a designated restricted speed, the train controls its running time to arrive at the next station in accordance with predicted delay. Second, the train predicts the time at which it will reach the current braking profile generated by Digital ATC, along with the time when the braking profile transits ahead. By comparing them, the train correctly chooses the coasting drive mode in advance to avoid deceleration due to the current braking profile. We evaluated the effectiveness of the proposed method regarding driving conditions, energy consumption, and reduction of delays by simulation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(3): 65–73, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.10020/eej.21080     

铸铁激光重熔技术在泥浆泵叶轮表面强化中的应用

介绍了利用ＧＪ－Ⅱ型连续ＣＯ２激光器对６ＳＰＳ正反循环两用流泵叶轮进行重熔处理的工艺方法，分析了重熔处理后表层的组织性能以及相关工艺参数的和渗层深度经重熔处理后的叶轮的使用寿命提高３倍以上。     

Materials for flexible riser systems: problems and solutions

Criteria to be satisfied in the selection of materials for unbonded flexible risers are first outlined. The paper then describes how three main types of thermoplastic and two classes of steel meet these requirements, and briefly discusses selection criteria and materials used for ancillary equipment for flexible riser systems     

武钢铁路车辆用耐候钢的开发

介绍了武钢生产的铁路车辆用耐候钢的特点，分析稀土对Cu—P系列耐候钢的作用机理，并介绍武钢正在开发的耐候钢新钢种。     

Activation Response of Martensitic Steels

A hypothetical martensitic steel has been compositionally designed in order to optimize both metallurgical and reduced activation properties. When compared with two other martensitic steels, its activation characteristics are shown to be superior for all activation indices examined. However, these excellent properties are found to be due to the assumed absence of deleterious tramp impurities. When limiting impurity concentrations are determined for the hypothetical steel, they are found to be extremely stringent, and wholly unachievable using industrial scale production methods. It is concluded that only slight improvements can be made to currently available low activation martensitic steels to reduce residual activity responses further.     

提高成庄铁路运输能力机务工作透析

通过对现有国内大功率货运内燃机车车型技术参数比较，结合成庄铁路纵断面和运行条件，选定东风4DD机车进行操纵图绘制分析，论证其可行性，并提出相关技术改造措施。     

提高大位移井固井质量方法

分析了大位移井固井的技术难点,从水泥浆的体系、套管的居中、附件的优选与应用、现场施工技术等方面进行了研究,提出了保证大位移井固井质量的技术措施,现场实践取得显著效果,形成了系统、成熟的大位移井固井技术.对大港油田大位移井固井质量的提高具有指导作用.     

Effects of low-temperature aging on AISI 444 steel

The consequences of aging at 400 and 475 °C on the mechanical properties, corrosion resistance, and magnetic properties of the ferritic stainless steel (SS) AISI 444 were investigated. Age hardening was measured as a function of aging time at both temperatures and was found to be more intense at 475 °C. The localized corrosion susceptibility increased, while the impact toughness decreased with aging time. These two effects were also more important at 475 °C. Unlike duplex SSs, AISI 444 did not present any variation in coercive force or Curie temperature with aging time. The effects on the Mössbauer spectra were also determined and analyzed.