18—8型奥氏体不锈钢晶间腐蚀分析及对策

钢中含有18％Cr、8％Ni为18-8型奥氏体不锈钢,如1Cr18Ni9、1Cr18Ni9Ti等广泛应用于石油化工、冶金机械、航空航海、仪器仪表、家用电器和五金制品等工业部门。该钢在常温和低温下有良好韧性、塑性、焊接性、抗蚀性及无磁性,室温组织为奥氏体。     

关于奥氏体不锈钢晶间腐蚀评定方法

本文探讨了焊缝金属腐蚀试样受拉面的纤维延伸率,在与国家标准规定的不锈钢焊条熔敷金属的延伸率以及不同厂家生产的不锈钢焊丝、焊剂熔敷金属的延伸率加以比较后,发现国家标准的规定较为苛刻,故建议有关技术部门进行适当修改。     

关于奥氏体不锈钢晶间腐蚀评定方法的修改建议

本文通过一系列试验,建议现行的奥氏体不锈钢晶间腐蚀试验标准中的弯曲评定参数进行适当的修改,以有利于工厂生产和检验。     

不锈钢复合板焊接接头晶间腐蚀失效分析

针对不锈钢复合板焊接接头出现晶间腐蚀裂纹问题,采用光学显微镜、扫描电镜、XRD等技术手段对复合板焊接接头的组织、成分以及相组成进行检测和分析,对焊接工艺规范和热处理制度对焊接接头耐蚀性的影响进行探讨。结果表明,接头焊缝区铁素体含量18．3％,晶粒度9．5级,过渡层焊缝铬的含量9．58％,低于耐蚀性要求;接头产生了σ等硬脆相,这些因素都增大晶间腐蚀敏感性;焊接线能量过大,将降低接头的腐蚀性能;复合板整体消应热处理可以取消。     

奥氏体不锈钢晶间腐蚀问题的研究及防止

晶间腐蚀是奥氏体不锈钢焊接过程中最危险的破坏形式之一。本文通过对晶间腐蚀产生原因的深入研究,提出了相应的防止方法,对提高产品的质量具有重要的指导意义。     

不同热处理工艺对奥氏体不锈钢焊接接头耐蚀性影响的探讨

1．概述 据统计,全世界每年因腐蚀而报废的钢材约占钢材年产量的1／4,因此材料受到腐蚀而失效是当今材料研究与发展的主要问题之一。为此,本文研究了几种热处理工艺对奥氏体不锈钢焊接接头耐腐蚀性的影响。     

奥氏体不锈钢焊接接头晶间腐蚀试验的理解与争议——探讨统一相关标准要求的可能性

不同国家和行业针对奥氏体不锈钢的晶间腐蚀试验制定了不同的标准。在晶间腐蚀试验的敏化制度、取样部位和方向、试样的尺寸、弯曲试验压头直径的选择、弯曲角度等方面,不同标准之间存在差异。此外,有些标准的规定不是很明确,造成理解上的分歧,在工程实际应用中引起不必要的争议。分析了不同标准之间的差异,结合晶间腐蚀试验的原理和目的,在达到考核材料耐晶间腐蚀性能的前提下,探讨统一相关标准要求的可能性。     

奥氏体不锈钢热轧板材的焊接性试验研究

通过焊接接头无损检测、力学性能、耐晶间腐蚀性能试验及显微硬度测定,研究了经手工钨极氩弧焊（TIG）SUS304热轧板材的焊接性能。结果表明,采用TIG焊接方法和较小的焊接规范,所得焊接接头各项性能良好;热影响区晶粒长大不严重,焊缝与母材熔合良好。利用双环动电位再活化法（DL-EPR）测定SUS304奥氏体不锈钢焊接接头的晶间腐蚀敏感性,发现其无晶间腐蚀倾向。     

关于奥氏体不锈钢晶间腐蚀敏感性试验的各种标准中一些问题的探讨

对各种标准中奥氏体不锈钢的晶间腐蚀敏感性检验的一些问题,如试样状态、敏化处理、弯曲试验、加铜、试验时间等进行了讨论。     

The effect of stainless steel structure on the performance of rubber-graphite under conditions of water lubrication

A new sliding bearing material based on rubber filled with different graphites was assessed against stainless steels of various structures under conditions of water lubrication in an Amsler machine. The tribological characteristics of the rubber-graphite depend upon the fillers used. The wear of stainless steel journals depends upon the material structure and the chromium carbide present.     

The effect of manufacturing variables on the corrosion resistance of a super duplex stainless steel

Recent in-service failures of super duplex stainless steel (SDSS) components have revealed the important role of manufacturing variables on the corrosion behaviour of the material. These variables include surface condition, heat treatment and cold work. The effect of all three variables on the corrosion behaviour of an example SDSS was investigated using electrochemical techniques, tensile testing and microscopic observations. The role of surface condition was investigated by characterising the topography of specimens using the surface roughness parameter, R _a, then measuring the critical pitting temperature. The results showed that R _a on its own is not sufficient to characterise the effect of surface condition on corrosion resistance. The effect of heat treatment on pitting potential was pronounced as a result of the intermetallic phases precipitated. Plastic deformation caused by cold work affected the pitting potential of the material, although the effects varied with increasing cold work; certain plastic strain levels caused reduced resistance, whilst others caused little change compared with the solution-annealed specimens. Hydrogen embrittlement increased with increasing cold work. The main conclusion is that the interactions between corrosive environments and SDSS components containing one or more of these manufacturing variables must be considered if reductions in service life are to be avoided.     

Influence of flow conditions on the corrosion of AISI 304L stainless steel

Hydrodynamic and electrochemical noise measurements (ENMs), of AISI 304L stainless steel, were made in a pipe test section of 28 mm inside diameter for a range of flow regimes from laminar to turbulent. Mean flow velocities through the test section were controlled at 0.04, 0.07, 0.11, 0.36, 1.8 and 2.7 m s⁻¹, equivalent to Reynolds numbers of 1000, 2000, 3000, 10 000, 50 000 and 75 000, respectively. Standard hydrodynamic parameters were employed to characterise and evaluate the complex interrelationship between the mass transfer rate of oxygen and momentum transfer through turbulence to the metal/solution interface. For AISI 304L stainless steel, pitting typically occurs in the form of metastable pits which either repassivated before achieving stability or grow to become stable pits. Metastable pitting was evident under all flow regimes. The fluid flow, whether laminar or turbulent, had little overall effect on the nucleation rates of metastable pitting events. Conversely, stable pit growth was most evident during laminar flow immediately before the transition to turbulent flow and close to the critical velocity (∼1.5 m s⁻¹).     

塔式起重机镀锌钢结构的耐腐蚀性

为了提高塔式起重机钢结构的使用寿命,以Q235碳钢为例对其表面采用无氨、无氰溶液镀锌以及钝化处理.并对镀锌试样在中性盐雾以及有机物质气氛下详细地进行了耐腐性能研究.结果表明：有机物质气氛是造成碳钢制品腐蚀的主要原因,而无氨、无氰溶液进行镀锌不仅具有良好的电化学保护作用和装饰性,还能在很大程度上解决碳钢表面的电化学腐蚀问题.     

热处理对马氏体不锈钢FV520B的组织和力学性能的影响

讨论研究热处理对马氏体不锈钢FV520B的组织和力学性能的影响,从而得出经1050℃固溶处理 850℃中间处理 470℃时效时FV520B钢的强度达到极大值。     

904L不锈钢复合板封头的焊接和热处理

分析了(Q345R+904L)复合板封头的制造特点,通过对封头拼缝焊接和热处理工艺的试验,封头制造由Q345R钢板冲压成型后堆焊904L的方法改为复合板直接冲压成型,基层和复层各项性能指标完全满足技术要求,降低了每个封头堆焊的成本,缩短了制造周期。     

不锈钢脚阀在酸性介质中使用寿命的研究

研究了2种阀门常用材料AISI 304和1Cr18Niu9Ti不锈钢在HNO3，H2SO4，H3PO4和HCl溶液中的腐蚀特征，给出了2种不锈钢在酸溶液中的腐蚀速率和不锈钢阀门在酸溶液中的使用寿命。     

酸性介质中双相不锈钢与铁素体不锈钢的应力腐蚀研究

采用慢应变速率拉伸试验(SSRT)、扫描电镜(SEM)断口分析以及金相显微组织分析等方法对TP405铁素体不锈钢及2205双相不锈钢在酸性介质中应力腐蚀开裂(PSCC)行为进行了研究.并评定铁素体不锈钢与双相不锈钢在酸性介质中应力腐蚀开裂的敏感性.为在酸性介质中选择容器用钢提供依据.结果表明,拉伸试样全部断裂在焊缝或热影响区.试样断口形貌呈准解理断裂和韧性断裂.2205双相不锈钢的应力腐蚀敏感性比TP405铁素体不锈钢低.     

Wear and corrosion wear of medium carbon steel and 304 stainless steel

Wear and corrosive wear involve mechanical and chemical mechanisms and the combination of these mechanisms often results in significant mutual effects. In this paper, tribological behavior, X-ray peak broadening, and microstructure changes of carbon steel AISI 1045 and stainless steel AISI 304 samples under simultaneous wear and corrosion were investigated and the results were compared with those obtained from dry wear tests. 3.5 wt.% NaCl solution was used as the corrosion agent and a pin-on-disk tribometer was employed to perform wear and corrosive wear tests.X-ray diffraction measurements have shown that by increasing the applied load, the worn surfaces of carbon steel samples reached a constant strain at which fracture and wear occurred. Whereas in 304 stainless steel samples, by increasing the applied load, broadening of X-ray diffraction peaks was decreased.Wear tests of carbon steel and stainless steel samples have shown smaller weight losses and lower friction coefficient in the presence of corrosive environment. Study of worn surfaces suggested that depending on wear environment and applied load, different features of wear mechanisms were involved.     

Machining of sintered steel under different lubrication conditions

Cutting experiments of sintered steel Fe–2Cu–0.8C under different lubrication/cooling conditions and with different tool materials were performed in order to clarify the reasons for the low machinability of the sintered steel, and investigate the applicability of minimum quantity of lubricant (MQL) to the machining of sintered steel. As a theoretical approach to the short tool life in machining sintered steel, the impacts to the cutting edge caused by micro-voids were theoretically modeled, and it was revealed that the cutting edge suffered from impacts at a very short interval causing high cycle fatigue. Extremely short tool life in dry machining of sintered steel already used for wet machining proved that coolant definitely increased the stress amplitude in high cycle fatigue. Application of the air jet to a tool showed the positive effect in reducing tool wear. This indicated the possibility that micro-cracks nucleated by high cycle fatigue were healed by oxidation. MQL cutting with small amount of oil and air jet is proved to be acceptable for machining sintered steel from the results of cutting experiments using uncoated and coated carbide and cermet tools. Finally, it is confirmed that thick coating of a carbide tool is effective for dramatically improving the machinability.