奥氏体不锈钢高温变形行为的研究

作者采用“ＴＨＥＲＭＥＣＭＡＳＴＯＲ－Ｚ”热加工模拟试验进行了奥氏体不锈钢高温变形模拟试验，实测了热轧时钢的变形过程中温度，变形速度和应变量对变形抗力的影响。通过试验得到了热变形时钢的真应力－真应变曲线，利用计算机进了试验数据的优化处理，建立了计算热轧和体不锈钢的变形贽数学模型。     

奥氏体不锈钢夹杂物控制工艺技术探讨

奥氏体不锈钢中的夹杂物影响钢材的抗腐蚀性能,对塑性、韧性和抗疲劳性能均有不利的影响。叙述了中航上大高温合金材料有限公司采用EAF+AOD+LF生产奥氏体不锈钢时夹杂物控制的主要工艺,分析了夹杂物的主要来源与产生机理,工艺设计时对冶炼过程夹杂物的控制进行了系统的策划。通过加强原辅材料控制,优化AOD脱氧制度,LF精炼采用钙处理和弱搅拌工艺对夹杂物进行变性处理,模铸浇注采用氩气保护浇注等技术手段,最终实现了钢中各类夹杂物含量的降低和稳定控制,满足了核电、压力容器等高端不锈钢管坯的质量要求。     

镜面抛光技术在奥氏体不锈钢产品中的应用

冷轧BA表面不锈钢在抛光装饰行业中作为镜面板加工基板得到广泛应用.着重介绍了抛光行业对镜面不锈钢表面的判定标准,并从抛光原理、设备、抛光溶液、工艺技术等方面介绍了电解抛光、化学抛光、机械抛光以及化学机械抛光等目前抛光行业最常见的四种镜面抛光技术;同时从设备要求、镜面板质量、加工效率、对环保影响等多方面对四种抛光技术的优劣进行了对比.收集了抛光镜面板过程中容易出现的缺陷,对其原因进行了分析,并提出了相应的解决方案.     

奥氏体不锈钢保护渣的研制

针对奥氏体不锈钢成分的特殊性及可能产生的夹杂物,提出了连铸保护渣的相应研制思路,以此开发的保护渣在宝钢集团浦钢公司进行了数十炉的工业试验。结果证明,研制的奥氏体连铸保护渣各项性能均取得了较为满意的结果,铸坯质量及轧制性能达到了用户要求。     

奥氏体不锈钢伸长率的换算

对奥氏体不锈钢不同标距间伸长率的换算公式进行研究,结果表明：试验所得n值约为0．199,与标准中Olive公式的规定值存在一定的差异。     

奥氏体耐热不锈钢的焊接实践

通过对奥氏体耐热不锈钢的焊接性分析，提出奥氏体耐热不锈钢焊接应采取的焊接工艺及应注意的问题．     

超级奥氏体不锈钢的发展

日益增长的工业需求推动着超级奥氏体不锈钢的研发,以研发时间为序阐述超级奥氏体不锈钢3个发展阶段。第1个阶段主要是为解决硫酸介质环境的耐腐蚀性而开发的不锈钢;第2个阶段是在第1阶段研发钢的基础上添加质量分数约为0.2%的N元素、并将Mo元素质量分数增加到约6%而研发的几种耐腐蚀性能良好的超级奥氏体不锈钢;第3个阶段是在6%Mo钢的基础上将Cr、Mo、N含量都进行较大幅度的提高,其中Mo元素质量分数增加到约7%,N元素质量分数控制在0.5%左右,并加入适量Mn元素而研发出耐腐蚀性优异的超级奥氏体不锈钢。阐述了超级奥氏体不锈钢研发过程中的2个重要技术,即炉外精炼与氮合金化技术,并展望了超级奥氏体不锈钢的未来发展及推广应用。     

Optimising process parameters for gas tungsten arc welding of an austenitic stainless steel using genetic algorithm

Automated Gas Tungsten Arc Welding (GTAW) with filler wire addition using a wire feeder is a candidate process for welding of 316LN austenitic stainless steel, which is the major structural material for the Indian 500 MWe Fast Breeder Reactors. In GTAW, the quality of the weld is characterized by the weld-bead geometry as it influences the mechanical properties and its performance during service. This paper discusses the development of computational model using genetic algorithm for determining the optimum/near-optimum GTAW process parameters for obtaining the target weld-bead profile during automatic welding of 316LN stainless steel. Using the experimental data generated on the influence of process variables on weld-bead geometry, regression models correlating the weld-bead shape parameters with the process parameters were developed for determining the objective function in genetic algorithm. Close agreement was achieved between the target weld-bead profile and the model-computed weld-bead profile. This study has shown that use of genetic algorithm is an appropriate methodology for optimising process parameters to obtain target weld-bead profile in GTAW with wire feeder of 316LN stainless steel.     

Irradiation-produced defects in austenitic stainless steel

Metallurgical and Materials Transactions B - The microstructure of annealed AISI Type 304 and type 316 stainless steels has been characterized by transmission electron microscopy as a function of...     

Study of Cu-rich phase precipitation in austenitic antibacterial stainless steel

Cu precipitation behaviors in two Cu-bearing austenitic antibacterial stainless steels,type 304 and type 317L,were systematically studied by using relatively simple methods for materials analysis,including micro-hardness,electrical resistivity,electrochemical impedance spectroscopy,X-ray diffraction and differential scanning calorimetry.The results indicated that after aging at elevated temperature,the micro-hardness, electrical resistivity,electrochemical impedance and lattice constant of the steel were all varied at different degrees due to the precipitation and growth of Cu-rich phases.The results also showed that the heat evolution during the process of Cu precipitation could be sensitively detected by means of differential scanning calorimetry,obtainning the starting temperature,peak temperature,peak area of the Cu-rich precipitation,and even the activation energy by calculation.The results confirmed that the Cu-rich phased precipitation in the Cu-bearing austenitic antibacterial stainless steel should be a thermal activation process controlled by Cu diffusion.All the materials analysis methods used in this study can be more simple and effective for application in R & D of the Cu-bearing antibacterial stainless steels.     

Surface segregation in austenitic stainless steel

We report in this paper a study of surface segregation in austenitic stainless steel. Auger electron spectroscopy was used to measure segregation as a function of time and temperature. We have found that P, N, S, Cr, and Ni will all segregate to the surface. However, their presence on the surface often depends on the competitive and attractive interactions between the various elements. We show that thermodynamic data on ternary liquid iron alloys are quite valuable in predicting these interactions. We also discuss possible applications of these studies.