光亮表面镀锡板及DI材的表面粗糙度试验研究

镀锡板表面粗糙度试验研究结果表明,生产光亮表面镀锡板时,提高平整辊粗糙度,可延长平整辊的使用寿命和提高原板的粗度,显著降低镀 锡板木纹、锡结晶、锡层及原反擦划伤等表面缺陷,并提高了镀锡板的使用性能,通过优化DI材平整辊配置,使DI材粗糙度得到稳定控制并养活了平整辊种类,提高了其利用率。     

时效制度对Al–Zn?Mg合金组织和抗应力腐蚀性能的影响

采用慢应变速率拉伸应力腐蚀、室温拉伸、透射电镜等检测方法，研究传统T5、T73时效处理，以及新型T5I4、T5I6断续时效处理对Al–Zn?Mg合金微观组织、室温拉伸性能及抗应力腐蚀性能的影响。结果表明:断续时效T5I4处理后材料抗拉强度为400.0 MPa，明显高于传统T5及T73态样品，但材料抗应力腐蚀性能变差，应力腐蚀敏感系数为5.7%；而经断续时效T5I6处理后，材料的抗拉强度为408.5 MPa，较T5I4态相比有所提升，与此同时抗应力腐蚀性能也得到明显改善，应力腐蚀敏感系数为3.2%，该值明显小于T5I4及T5态；T5I4态晶内析出相平均粒径为2.0 nm，体积分数为8.8%，均明显小于其他3种时效制度，其晶界析出相为细小且连续分布的点状析出相；而经T5I6时效处理后晶内析出相体积分数为24.6%，明显大于其他3种时效制度，晶内析出相平均粒径（4.1 nm）较T5I4态有所增大，但依然小于T5、T73态，其晶界处析出相与T5I4态相比更加粗大，呈断续分布形貌。      

低铬抗硫套管的H_2S/CO_2腐蚀行为研究

通过高温高压及H2S应力腐蚀开裂(SSC)实验,采用SEM、EDS、XRD和TEM技术,研究3Cr110S在模拟环境中的H2S/CO2腐蚀行为。结果表明:在模拟H2S/CO2高温高压腐蚀环境中,H2S腐蚀占主导作用,3Cr110S的均匀腐蚀速率为0.1272 mm/a,局部腐蚀轻微,试样表面腐蚀产物为FeS;在施加应力为72%、80%的最低屈服强度时,3Cr110S试样均未发生应力腐蚀开裂,具有良好的抗SSC性能;3Cr110S回火索氏体组织的条束之间位相差大,铬元素在晶界及晶内以粒状碳化物析出、位错纠结、弥散分布碳化物的位错定扎对SSC裂纹扩展起着良好的阻碍作用。     

Stress corrosion cracking of superplastically formed 7475 aluminum alloy

The effects of biaxial superplastic deformation and postforming heat treatment upon the stress corrosion cracking (SCC) of a fine-grained 7475Al alloy plate have been investigated. For all postforming tempered conditions, increasing the extent of superplastic deformation, which created more cavitations, would decrease the mechanical properties, the SCC resistance, and the corrosion resistance. The influence of cavitation on the decay of elongation of the superplastically formed workpieces is larger than that on the decay of its strength. Post-forming tempered by retrogression and reaging (RRA) treatment could effectively improve the SCC resistance of workpieces in postforming T6 temper while not sacrificing the strength. However, the benefit of improving the SCC resistance by means of the postforming RRA temper was decreased with increasing the extent of superplastic deformation, because the SCC susceptibility increased as the extent of superplastic deformation increased for each postforming tempered condition. The cavitation led to more anodic corrosion potential and pitting potential and to an increase in both corrosion current density and passive current density, which would increase the SCC susceptibility.     

化学成分及退火温度对镀锡板调质度的影响

采用50kg真空炉及模拟退火炉进行冶炼和退火试验,结合硬度、拉伸试验及金相分析,研究了镀锡原板中的w(C)和退火温度对调质度的影响。结果表明,在相同的退火温度条件下,随着镀锡原板中w(C)增加约0.001%,镀锡板的洛氏表面硬度值(HR30Tm)增加约5,其强度增加5～10 MPa,而伸长率下降约1.5%;在w(C)不变的条件下,随着退火温度的上升,镀锡板的洛氏表面硬度值下降。     

镀锡板的电化学剥离及其耐蚀性研究

镀锡板是指两面镀有一层极薄金属锡的冷轧薄钢板,它将钢的硬度和强度与锡的抗腐蚀性和光亮的外表集于一体。实验用电化学法将镀锡板的钝化膜、纯锡层、合金层逐层剥离,通过阴极极化曲线、交流阻抗等电化学技术研究其电化学性能,用扫描电镜(SEM)观察剥离后各层的表面形貌,用X射线光电子能谱仪(XPS)对镀锡板铬酸盐钝化膜中铬元素的价态进行了分析。结果表明,电化学法剥离的效果十分理想,可以用于镀锡板表面不同层的形貌观察,同时还可以用于镀锡板的耐蚀机理研究。除掉钝化膜后,腐蚀电流密度从1.48 μA/cm²增大到3.5 μA/cm²,除掉纯锡层后,腐蚀电流密度从3.5 μA/cm²增大到18 μA/cm²,镀锡板良好的耐腐蚀性主要来源于纯锡层和钝化膜的作用。镀锡板铬酸盐钝化膜中铬元素主要以氢氧化铬、金属铬和三氧化二铬等形态存在。     

镀锡薄钢板高温氧化的研究

采用明度差法表征镀锡薄钢板表面的高温氧化产物的量。通过研究明度差法与常规方法的相关性，发现用明度差法可以更为详细地描述钢板的高温腐蚀程度，并采用该法研究了镀锡钢板在高温条件下的化馆速率与和温度的关系，发现在不同的温度范围内，镀锡薄钢板表面高温氧化腐蚀的动力学方程各不相同。通过对氧化前后试片极化曲线的测定，发现经闹温化后镀锡层的稳定电位发生了变化，通过扫描电镜与Ｘ射线能谱分析确认了镀锡薄钢板的氧化     

The effect of microstructure on the hot salt stress corrosion susceptibility of titanium alloys

It was the purpose of this study to identify what metallurgical processes could be applied to commercial structural titanium alloys to increase the hot salt stress corrosion (HSSC) threshold stress and therefore increase their range of application. Toward this purpose Ti-6A1 and Ti-6A1-4V were evaluated as a function of microstructural variables. Specifically, it was shown that both increasing amounts of cold work and increasing grain size decrease HSSC resistance of Ti-6A1. Also, for Ti-6A1-4V it was shown that preferred orientation can have a profound effect on the HSSC resistance. Crack initiation time, crack growth rate, and stress rupture life were evaluated in Ti-6A1-4V as a function of applied stress at 727 K. These results indicate that HSSC cracking can be described by a critical resolved shear stress criterion, and that increased high temperature creep resistance and decreased room temperature notch rupture strength combine to increase HSSC susceptibility and embrittlement.     

The effect of microstructure on the hot salt stress corrosion susceptibility of titanium alloys

It was the purpose of this study to identify what metallurgical processes could be applied to commercial structural titanium alloys to increase the hot salt stress corrosion (HSSC) threshold stress and therefore increase their range of application. Toward this purpose Ti-6A1 and Ti-6A1-4V were evaluated as a function of microstructural variables. Specifically, it was shown that both increasing amounts of cold work and increasing grain size decrease HSSC resistance of Ti-6A1. Also, for Ti-6A1-4V it was shown that preferred orientation can have a profound effect on the HSSC resistance. Crack initiation time, crack growth rate, and stress rupture life were evaluated in Ti-6A1-4V as a function of applied stress at 727 K. These results indicate that HSSC cracking can be described by a critical resolved shear stress criterion, and that increased high temperature creep resistance and decreased room temperature notch rupture strength combine to increase HSSC susceptibility and embrittlement.     

激光功率对碟阀表面熔覆Ni 基合金涂层性能的影响

采用半导体激光器在2205双相不锈钢表面激光熔覆Ni基合金涂层.借助扫描电镜、电化学综合测试仪和硬度测试仪等,探讨了激光功率对涂层稀释率、微观组织、耐腐蚀性能及硬度的影响.结果表明:激光功率越大,涂层稀释率越大,熔覆层与基体元素发生更多的对流扩散;熔覆层的耐腐蚀性能随激光功率的增加而降低,当激光功率为2.7 kW时,熔覆层的自腐蚀电位最低,为-0.46 mV,腐蚀电流最小,为3.47×10-5 A/cm2. 硬度测试实验表明,激光熔覆Ni基合金涂层硬度最高达680 HV,约为基体硬度的2.5倍.      

含锶钪2099型铝锂合金的晶间腐蚀和剥落腐蚀性能

采用维氏硬度计(HV)、金相显微镜(OM)和扫描电镜(SEM)显微分析技术,研究了一种锶钪复合微合金化2099型铝锂合金(其化学成分为:Al-2.57Cu-1.86Li-1.31Zn-0.420Mg-0.321Mn-0.0735Zr-0.0943Sr-0.0433Sc)的晶间腐蚀性能和剥落腐蚀性能。结果表明,该合金经均匀化退火处理(475℃×24 h)、热锻压变形加工处理(三次变形量均约为100%)、固溶处理(540℃×2 h)、冷水淬火(水温大约5℃)、T8时效处理(121℃×14 h+151℃×48 h)后,合金显微硬度值达到174.6 HV,比2024-T6合金(固溶处理500℃×2 h+时效处理191℃×12 h)高23.1%。合金具有良好的抗晶间腐蚀性能和抗剥落腐蚀性能,其抗腐蚀性能明显优于2024-T6合金。该合金Sr,Zr,Sc的复合微合金化作用(细化粗大第二相、抑制再结晶和晶粒长大),第二相分散、分布不连续,以及Zn的含量高,是合金抗腐蚀性能高的主要原因。研究结果还说明了微量复合添加对铝锂合金具有奇效微合金化作用的过渡族金属元素Sr,Sc,是得到抗腐蚀性能良好的铝锂合金的一种有效途径。     

Caustic stress corrosion cracking of NiCrMoV rotor steels—The effects of impurity segregation and variation in alloy composition

This paper reports a study of the effects of phosphorus, tin, and molybdenum on the caustic stress corrosion cracking susceptibility of NiCrMoV rotor steels. Constant load tests were performed on these steels in 9M NaOH at 98 ± 1 °C at a controlled potential of either -800 mV_Hg/Hgo or -400 mV_Hg/Hgo. Times to failure were measured. The results show that at a potential of -400 mV_Hg/Hgo the segregation of phosphorus to grain boundaries lowers the resistance of these steels to caustic stress corrosion cracking. When molybdenum is removed from a steel that has phosphorus segregated to the grain boundaries, the steel’s resistance to stress corrosion cracking is improved. High purity alloys, both with and without molybdenum, show very good resistance to caustic cracking at this potential. At-800 mV_Hg/Hgo segregated phophorus has no effect; only molybdenum additions lower the resistance of the steel to caustic stress corrosion cracking. Segregated tin has little effect at either potential. Metallographic examination shows that one explanation for these results is that molybdenum and phosphorus, probably as anions precipitated from solution, aid in passivating the sides of the crack and thus help keep the crack tip sharp. This sharpness will increase the speed with which the crack will propagate through the sample. Furthermore, removal of molybdenum greatly increases the number of cracks which nucleate. This higher crack density would increase the relative area of the anode to the cathode and thus act to decrease the crack growth rate. Formerly with the Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA.     

高品质镀锡板生产技术与夹杂物控制

介绍了成分对镀锡基板的性能影响,综述了镀锡基板的典型缺陷。介绍了镀锡板夹杂物的控制技术以及目前国内典型的工艺流程。最后针对某厂镀锡板铸坯的夹杂物,分析其夹杂物产生的原因为拉速不当致结晶器卷渣,并根据结晶器物理模拟结果确定合理的控制措施。     

耐腐蚀软质镀锡板性能分析

通过采用扫描电镜（SEM）、酸浸时滞试验、合金-锡电偶试验等仪器,对研制的MR T-2.5BA耐腐蚀软质镀锡板性能进行了检测与分析,结果表明：MR T-2.5BA镀锡板具有优良的耐蚀及冲压成形性能,各项性能（镀锡量、硬度值、PL值、ATC值等）均达到《GB/T2520-2008》规定的指标;试制产品经用户试用,其性能满足制作各种耐蚀罐要求。     

Influence of force variations in skin pass rolling on texture and surface reactivity of hot dip galvanised low carbon steel sheets

Abstract

In this research work, the skin pass rolling force was changed in the range of 50 to 200 kN in steps of 30 kN. The crystallographic orientation of the coatings was determined using X-ray diffraction, and texture parameters were calculated. Corrosion behaviour was assessed employing the Tafel polarisation test. It was concluded that by increasing the force the texture coefficient of the basal planes component in the coating would be decreased and conversely, other components such as prismatic planes components would be strengthened. Increasing skin pass force would also cause an increase in surface roughness and microcracks in the coating. Such increasing in prismatic component texture coefficient, roughness and microcracks of the coating would result in the decreasing of coating corrosion resistance.     

晶粒尺寸对316H奥氏体不锈钢550 ~ 650°C 360 ~ 165 MPa持久性能的影响

研究了316H奥氏体不锈钢28 mm板晶粒尺寸对550～650℃360～165 MPa持久性能的影响,分析了断裂机理。在温度550℃、应力360 MPa和335 MPa条件下,小晶粒尺寸(44.5μm)钢板的持久断裂时间仅为大晶粒尺寸(89.6μm)钢板的48.92%和51.98%,持久断裂由晶界处楔形裂纹引起,晶粒尺寸对持久性能影响较大,较高的应力会使得晶粒尺寸对持久性能的影响进一步加大;而在温度650℃,应力165 MPa条件下,44.5μm小晶粒钢板的持久断裂时间达到89.6μm大晶粒钢板的91.35%,持久断裂则由晶界空洞的形成长大相互连接引起,晶粒尺寸对持久性能影响较小。     

Corrosion resistance and ion dissolution of titanium with different surface microroughness

In vitro corrosion resistance and ion dissolution of commercial pure titanium with different surface microroughness are studied adopting constant potential meter and atomic absorption spectroscopy. In terms of the surface roughness, titanium samples are divided into 5 groups: smooth surface, machining surface, 2 different microroughness surfaces and macrorough surface. Each group contains three category samples under different treatments: natural oxidation (24 h exposure to air), oxidation under 400 degrees C (400 degrees C, 45 min thermal oxidation), oxidation under 700 degrees C (700 degrees C, 45 min thermal oxidation). In Hanks corrosion media, comparative studies through constant potential anode polarization curves and titanium release rates of the 5 groups of Ti samples demonstrates that oxidation under 400 degrees C best increase corrosion resistance and decrease ion release sharply, oxidation under 700 degrees C is better than natural oxidation. Ti samples with a different surface roughness all have good corrosion resistance and their corrosion resistance drop with the raising of surface roughness. Comparing with macrorough surface and machining surface, microrough surfaces have better corrosion resistance and a lower ion release rate which are similar to those of smooth surfaces. Moreover, the corrosion resistance of machining surface Ti is the lowest. It is hypothesized that surface treatment methods such as surface thermal oxidation, surface aging and so on will improve the corrosion resistance and decrease the ion release rate of rough surface effectively by increasing the thickness of surface protection film, improving its structural uniformity and facilitating the formation of ordered, compact surface protection film.     

Corrosion resistance and mechanical properties of (Ho,Nd)FeB magnets

(Ho,Nd)FeB magnets with different Ho contents were prepared by Ho substitution for part of Nd during the casting process. Effects of Ho contents on the corrosion resistance and mechanical properties of (Ho,Nd)FeB magnets were analyzed by a highly accelerated aging tester, an electrochemical workstation, a microhardness tester, a bending tester, a scanning electron microscope and an X-ray diffractometer. Results show that the addition of Ho can change the main phase structure, optimize the distribution of rare-earth rich (RE-rich) phases in grain boundary, and improve the corrosion resistance and mechanical properties of NdFeB magnets. When the content of Ho increases from 0 to 21.0 wt%, the weight loss of magnets decreases from 2.672 to 0.933 mg/cm², and the microhardness and bending strength increase from 528.74 HV and 374.92 MPa to 633.84 HV and 459.80 MPa, respectively.     

Dependence of Crystallographic Orientation on Pitting Corrosion Behavior of Ni-Fe-Cr Alloy 028

The influence of crystallographic orientation on the pitting corrosion behavior of Ni-Fe-Cr alloy 028 was studied using a combination of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), potentiodynamic polarization technique, and atomic force microscopy (AFM). The results show that there is anisotropy of pitting corrosion that strongly depends on crystallographic orientation of the surface plane. The distribution of pit density in a standard stereographic triangle indicates that the crystallographic planes close to {100} are more prone to pitting corrosion compared to planes {110} and {111}. The surface energy calculation of (001) and (111) shows that the plane with a high atomic packing density has a low surface energy with concomitant strong resistance to pitting corrosion. A correlation function between crystallographic orientation and pitting corrosion susceptibility suggests a method that not only predicts the pitting resistance of known textured materials, but also could help to improve corrosion resistance by controlling material texture.     

碳化硅复合镍磷合金涂层的组织结构、显微硬度及腐蚀性能研究

镍基复合涂层是一项有望替代电镀铬涂层的先进绿色环保表面处理技术。 本文在铝合金表面制备了纯 Ni、 NiP及其与SiC复合涂层, 利用SEM、 EDS和XRD研究了Ni、 NiP及其复合涂层的微观形貌、 成分与组织结构, 利用显微硬度计与电化学工作站研究了其硬度与耐腐蚀性能。 研究结果表明： SiC 复合电镀纯镍涂层的表面较为 粗糙, SiC 复合电镀镍磷合金涂层中晶粒轮廓明显; 电沉积镍磷合金涂层的相结构包括晶体 Ni2P、 Ni12P5 和非晶 NiP。 铝合金基体表面 Ni-P 合金涂层的显微硬度显著高于纯 Ni 涂层, 引入 SiC 纳米颗粒形成复合涂层可提高其 显微硬度; SiC 颗粒有助于提高复合涂层在氯化钠溶液中的腐蚀电位, 降低腐蚀电流密度, 提高其耐蚀性能。