Energetics of Plastic Deformation of Metastable Austenitic Stainless Steel

The change in the internal energy during uniaxial tensile deformation of austenitic stainless steels EN 1.4301 (AISI 304) and EN 1.4318 (AISI 301LN) was determined by measuring the extent of γ→α'‐martensite transformation and the temperature increase of the samples. From the results the fraction of the stored energy of cold work and the free energy change related to the strain‐induced γ→α'‐martensite transformation were determined. The fraction of stored energy varied around 0.4. With the metastable steel grades the free energy change related to the γ→α'‐martensite transformation was found to vary between ‐98 MJ/m³ and ‐206 MJ/m³ depending on the austenite stability of the steel. Furthermore, the magnitude of the mechanical driving force was estimated by comparing the results with the free energy change of thermally induced transformation.     

我国不锈钢焊接工艺研究现状及进展

随着我国不锈钢消费量的快速增长，不锈钢的焊接技术越来越重要，它直接影响着不锈钢的使用质量和应用领域的拓宽。本文总结了我国不镑钢焊接工艺的研究现状和发展趋势。     

Microstructural Modelling of Nb Microalloyed Steels during Thin Slab Direct Rolling Processing

The microstructural evolution during the hot rolling of coarse grain sized austenite has been modeled considering all the microstructural mechanisms (dynamic, static and metadynamic recrystallization, strain induced precipitation) that can take place during an industrial TSDR production of three Nb microalloyed steels. Based on the results obtained from the model, processing maps have been drawn for 0.02%, 0.035% and 0.05% Nb microalloyed steels. Optimum processing conditions to exploit all the benefits of the Nb microalloying have been defined considering a final gauge thickness range between 1.5 and 12.65 mm. In addition, and facing the difficulties present in the production of thick hot strip, several alternative thermomechanical schedules are proposed, which would originate microstructures with a suitable combination of homogeneity and retained strain prior to transformation.     

煤气管道膨胀节腐蚀和在线包焊技术应用

简单分析了高炉煤气中Cl元素的存在对不锈钢膨胀节的应力腐蚀问题和防止途径，作为一种临时性的防范措施，简要介绍了煤气膨胀节包焊实施步骤和措施。     

Pitting corrosion of Cr–Mn–N steel in sulphuric acid media

The resistance to pitting corrosion of austenitic stainless steel Cr18Mn12N has been studied in model solutions of sulphuric acid (0.5 m) containing chloride ions (0.5 m). The cyclic potentiodynamic method has been employed to investigate the effects of chloride ions and agitation rate on the pitting and repassivation potentials. Electron and optical microscopy, electron diffraction spectroscopy and atomic absorption spectrometry have been used to detect the surface sites for pit formation and the growth of pit nuclei. The results obtained with chromium–manganese–nitrogen steel have been compared with those of austenitic Cr18Ni9 stainless steel. A similarity in pit initiation is established, while steel composition exhibits no significant effect. Cr18Mn12N steel is less prone to repassivation as compared with Cr18Ni9 steel.     

Tribology of nitriding layer, TiN coatings and their complex on AISI D2 steel

The sliding wear and impact wear resistances of D2 steel with nitriding layer, PVD titanium nitride coating and their duplex treatment were investigated. The experimental results suggest that the duplex treatment has the best sliding and impact wear resistances under experimental conditions. And the wear resistance of PVD titanium nitride is better than that of nitriding. The impact wear resistance and wear mechanism of all three surface layers remain unchanged under impact load of 0.2 J or 1 J. All samples end with the same symptom of flaking.     

浅议超深孔钻孔灌注桩施工工艺

结合工程实例，浅议超深孔厚砂层钻孔灌注桩施工工艺。根据地层特点及设计要求，选用、优化钻头结构和钻进参数。．     

提高00Cr18Ni10钢焊缝抗裂性的研究

采用高含铬量超低碳不锈钢焊丝和专门研制的含铬陶质型焊剂两种方案研究了００Ｃｒ１８Ｎｉ１０不锈钢坦弧自动焊时焊缝的抗裂性，试验结果表明：以上两种途径，均可有效地防止焊缝金属中出现表面热裂缝。采用后者更为经济，现已用于生产。     

信息高速公路与电子信息产业

信息高速公路是信息社会的支柱，电子信息产业是信息社会中国家经济的支柱产业。本文在对信息高速公路具体内容进行了介绍的基础上，对信息高速公路技术结构进行了分析，对信息高速公路与电子信息产业及国民经济发展的重要关系进行了阐述。