The Recovery of Elastic Properties at 35 °C in TRIP 700 Steel Following Deformation

The influence of plastic deformation on the elastic properties that determine the magnitude of springback following forming was investigated using dynamic modulus analysis. For this study, the elastic modulus of TRIP 700 steel was measured continuously at 35 °C and a loading frequency of 1.0 Hz for 1000 min following deformation by cold rolling to varying levels up to 27%. The elastic modulus increased at an exponentially decaying rate during these experiments and with a magnitude that increased with pre-strain. These observations are consistent with the hypothesis that deformation creates microstructural defects that contribute compliance when the stress state changes and that these defects are removed by annealing at this low temperature. This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati, OH, October 15-19, 2006.     

Surface physico-chemistry study of an austenitic stainless steel: Effect of simple cold rolling treatment on surface contamination

The surface physico-chemistry properties of stainless steel and the effects of a cold rolling treatment were investigated. X-ray photoelectron spectroscopy (XPS) analyses were carried out on rolled surfaces at different rates. Thus, by characterizing passive film chemistry and contamination layer, the modifications due to this treatment were quantified, in particular an increase of the ratio (Fe/Cr)_oxide is evidenced with the level of the cold rolling treatment. Moreover, based on an angle resolved analysis, a new model where the contamination layer is represented as isolated parts was developed in order to describe the geometry of this carbon contamination. XPS experiments show an iron enrichment of the passive film during the cold rolling treatment, which seems to be explained by a surface heating during the mechanical treatment. Therefore, the new island model puts in evidence the effects of ageing time and surface condition on the geometry of carbon contamination. Hence, cold rolling increases the thickness and the recovery of carbon contamination on the stainless steel surface.     

CM690锚链钢开裂原因分析

对CM690锚链钢进行裂纹形貌、金相组织、夹杂物及低倍的检验和分析,结果表明,锚链的开裂是由于连铸坯中的细小裂纹及热处理工艺控制不当造成的.     

316不锈钢藕状多孔结构的选区激光烧结制备

研究了一种新型的制备金属藕状多孔结构技术——选区激光烧结，着重说明该技术的基本原理和工艺过程，并利用此制备技术成功获得了藕状多孔试样。利用SEM分析了316不锈钢藕状多孔试样的微观孔隙特征，并测定其孔隙率，结果表明其孔径大小分布均匀（2-4μm），平均孔隙率约为60％，孔隙贯通性良好；初步探讨了选区激光烧结制备316不锈钢藕状多孔结构的成形机制。     

The influence of sulphate-reducing bacteria biofilm on the corrosion of stainless steel AISI 316

This work investigates microbially-influenced corrosion (MIC) of stainless steel AISI 316 by two sulphate-reducing bacteria, Desulfovibrio desulfuricans and a local marine isolate. The biofilm and pit morphology that developed with time were analyzed using atomic force microscopy (AFM). Electrochemical impedance spectroscopy (EIS) results were interpreted with an equivalent circuit to model the physicoelectric characteristics of the electrode/biofilm/solution interface. D. desulfuricans formed one biofilm layer on the metal surface, while the marine isolate formed two layers: a biofilm layer and a ferrous sulfide deposit layer. AFM images corroborated results from the EIS modeling which showed biofilm attachment and subsequent detachment over time.     

Nucleation of corrosion pits in Ringer’s solution containing bovine serum

The effects of the presence of bovine serum on the nucleation of corrosion pits on 316L stainless steel and commercially pure titanium in Ringer’s physiological solution at 37 °C are presented. The experiments involved measurement of current transients generated on microelectrodes under potentiostatic control below the pitting potential. Results show that the presence of the organic components of the serum stimulates the nucleation of pits on 316L stainless steel. A similar but smaller effect is shown for commercially pure titanium.     

00Cr17Ni14Mo2不锈钢高压管道焊接工艺

通过对某项目00Cr17Ni14Mo2厚壁超低碳不锈钢高压管道化学成分分析,对管道进行焊接工艺评定从而制定了正确的焊接施工工艺,保证了该项目00Cr17Ni14Mo2超低碳不锈钢高压管道的焊接质量,为类似的管道焊接提供了技术工艺和参数.     

钻井工具的MAG焊接工艺

在对钻井工具的焊接特点、MAG焊接缺陷进行分析的基础上，通过选择合适的焊接材料、优选焊接工艺参数、采用合理的环缝焊接操作技术，克服了MAG焊易出现的气孔、熔化区开裂缺陷，焊缝金相组织为回火索氏体，成功的将MAG焊应用到了钻井工具制造领域，提高了焊接效率、降低了焊接成本。     

Fe和两种工业钢在500℃含氯气氛中ZnCl2-KCl盐膜下的腐蚀

研究了纯Fe,NF616和SS304钢在500℃含氯气氛中ZnCl2-KCl盐膜下的腐蚀行为.结果表明,3种材料都发生了加速腐蚀,生成了较厚的氧化膜,且在氧化膜与基体金属之间出现了熔融状氯化物混合盐.此外,合金在此环境中的抗腐蚀性随其Cr含量的提高而显著提高,这是在腐蚀过程中氧化膜内层出现了Fe-Cr尖晶石或Cr2O3阻挡了金属离子快速向外扩散的结果.讨论了材料发生加速腐蚀的机制.     

不锈钢表面的电化学机械复合抛光

介绍了一台由立式铣床改装的电化学机械复合抛光装置。讨论了加工电压、磨轮压力与加工效率的关系以及加工电压对表面粗糙度的影响。