John F. Kennedy Space Center (KSC) has equipment and processes which require the passivation of stainless steel. The standard practice for passivation uses nitric acid. While nitric acid exhibits excellent performance, there are a number of environmental and safety issues: nitrogen oxide (NOx) emissions are considered greenhouse gases, NOx are volatile organic compounds that contribute to smog, NOx increase nitrogen loading (oxygen depletion) in bodies of water, nitric acid can remove beneficial heavy metals (nickel, chromium, etc) from surfaces, and worker safety issues. The longtime military specification for passivation of stainless steel was Federal Specification QQ-P-35 (Passivation Treatments for Corrosion-resistant Steel), but that has been cancelled in favor of American Society for Testing and Materials (ASTM) A 967 (Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts) and Aerospace Material Specifications (AMS) 2700 (Passivation Treatments for Corrosion-resistant Steel). Both of the new specifications allow for the use of citric acid in place of nitric acid. In addition, KSC also uses NASA-STD-5005 (Standard for the Design and Fabrication of Ground Support Equipment) and ASTM A 380 (Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems). The primary objective of this effort is to demonstrate and validate citric acid as an alternative to nitric acid for the passivation of stainless steels. Citric acid offers a variety of benefits: it is naturally occurring and biodegradable; upon disposal, it is rarely classified as a hazardous waste; it does not remove beneficial heavy metals from surfaces; and there are no toxic fumes created during the passivation process. This project is follow-on to United Space Alliance (USA) work to optimize the parameters for the use of citric acid and verify effectiveness. USA evaluated the following parameters during their effort: concentration, temperature, and dwell time. This project will use the results from that testing to determine what process parameters will be used in the preparation of test coupons. This Test Protocol contains the critical requirements and tests necessary to qualify citric acid as an alternative to nitric acid for use at KSC. These tests were derived from engineering, performance, and operational impact (supportability) requirements defined by KSC participants. A Test Report will document the results of the testing as well as any test modifications made during the execution of the testing. The Test Report will be made available as a reference for future pollution prevention endeavors by other NASA centers, the Department of Defense, and commercial users to minimize duplication of effort. Users of this Test Protocol should check the project's Test Report for additional test details or minor modifications that may have been necessary in the execution of the testing. The technical stakeholders will have agreed upon test procedures modifications documented in the Test Report.

关键词：柠檬酸;耐腐蚀;硝酸;被动;污染控制;不锈钢

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4Cr5MoSiV1 steel,a widely used for hot work mould,contains Cr,Mo,V alloying elements that easily form carbides.The Micro-area chemical composition,microstructure,impact toughness and thermal fatigue behavior of 4Cr5MoSiV1 and 4Cr5MoSiV1H steels were investigated,the latter was carried on high temperature homogenizing and solution based on the former.The results showed that bulk eutectic carbides and elements segregation contained in the 4Cr5MoSiV1 steel reduced the impact toughness.But the impact toughness of the core of the mould steel block and thermal fatigue property of 4Cr5MoSiV1H steel were improved because the elements segregation and eutectic carbides was eliminated through the high temperature homogenizing and solution.

关键词：钢；高温均匀化；元素偏析；力学性能

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关键词：钢铁；形状记忆合金；执行器；二元合金

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This investigation was prompted by results of a qualification test of a mechanism to be used for the James Webb Space Telescope. Post-test inspections of the qualification test article revealed some loose wear debris and wear of the steel rollers and the mating Ti6Al4V surfaces. An engineering assessment of the design and observations from the tested qualification unit suggested that roller misalignment was a controlling factor. The wear phenomena were investigated using dedicated laboratory experiments. Tests were done using a vacuum roller rig for a range of roller misalignment angles. The wear in these tests was mainly adhesive wear. The measured wear rates were highly correlated to the misalignment angle. For all tests with some roller misalignment, the steel rollers lost mass while the titanium rollers gained mass indicating strong adhesion of the steel with the titanium alloy. Inspection of the rollers revealed that the adhesive wear was a two-way process as titanium alloy was found on the steel rollers and vice versa. The qualification test unit made use of 440F steel rollers in the annealed condition. Both annealed 440F steel rollers and hardened 440C rollers were tested in the vacuum roller rig to investigate possibility to reduce wear rates and the risk of loose debris formation. The 440F and 440C rollers had differing wear behaviors with significantly lesser wear rates for the 440C. For the test condition of zero roller misalignment, the adhesive wear rates were very low, but still some loose debris was formed

关键词：合金;滚筒；钢；钛合金；钒合金

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Based on the shape detecting principle and the digital signal technology,a new shape meter was developed thorough theoretical analysis and industrial adjustment to develop the shape detecting roll,the shape signal processing method,the original signal compensation mechanism and so on.The shape meter has good performance and stability,which can effectively avoid the scratchof steel strip surface,accurately detect real online strip shape and provide accurate online shape datum for shape control system.It was applied in 1250 mm cold rolling mill,the actual industrial tests prove that the shape signal was stable and reliable,met the harsh condition and the online technical requirements,and could improve shape quality significantly.

关键词：钢铁；冷轧带钢；冷轧机；板形仪

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Fine balance between active galvanic and passive barrier corrosion protection by zinc-rich hybrid paints is explored depending on the absolute and relative amounts of the electrically semi-conducting particles, viz. polypyrrole (PPy) modified alumina hydrate and multi-walled carbon nanotubes (MWCNTs) and the zinc pigments. The former was varied between 3.21 and 1.75 wt., the latter was altered from 70 to 80 wt.in the primers. The coating with less zinc indicated firm and stable barrier nature in a 254 h immersion test whereas the primer with greater zinc content afforded superior galvanic corrosion prevention in salt-mist test over 142 days. Different nature of the coatings are expounded on the basis of structure and 3D arrangement of the nano-size inhibitor particles in the epoxy vehicle besides interpreted considering varied grain contents caused changing electrical percolation and electrolytic conductivity of the primers.

关键词：钢铁;纳米管;低碳钢;富锌涂料

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Oak Ridge National Laboratory has been investigating a new class of Fe-based amorphous material stemming from a DARPA, Defense Advanced Research Projects Agency initiative in structural amorphous metals. Further engineering of the original SAM materials such as chemistry modifications and manufacturing processes, has led to the development of a class of Fe based amorphous materials that upon processing, devitrify into a nearly homogeneous distribution of nano sized complex metal carbides and borides. The powder material is produced through the gas atomization process and subsequently utilized by several methods; laser fusing as a coating to existing components or bulk consolidated into new components through various powder metallurgy techniques (vacuum hot pressing, Dynaforge, and hot isostatic pressing). The unique fine scale distribution of microstructural features yields a material with high hardness and wear resistance compared to material produced through conventional processing techniques such as casting while maintaining adequate fracture toughness. Several compositions have been examined including those specifically designed for high hardness and wear resistance and a composition specifically tailored to devitrify into an austenitic matrix (similar to a stainless steel) which poses improved corrosion behavior.

关键词：钢铁；不锈钢；粉末冶金；非晶材料

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Brillouin-scattering Optical Time Domain Reflectometry (BOTDR) is a viable technology for simultaneous, distributed strain and temperature measurements for miles-long transportation structures. It is a promising tool to ensure the smooth operation and safety of bridge structures that are key links in surface transportation networks or between various transportation modes: i.e., from airport to train station. Currently, telecom-grade optical fibers are widely used in civil engineering for strain and temperature measurements. These fibers are very fragile and easy to break during installation and measurement. In order to understand the ultimate behavior of structures, more rugged optical fibers such as carbon/polyimide coated fibers were recently proposed. One laboratory study on two single fibers indicated that new carbon/polyimide coated fibers can sustain a maximum strain of up to 4, which can survive any local crack in concrete members or buckling in steel members once they are installed on the structural members. This project aimed to characterize the ruggedness and signal loss of various packaged optical fibers and validate their performance as sensors. Among the tested optical fibers, bare single-mode fibers (SMF-28) with uncoated anchoring have the lowest shear strength and the lowest ultimate strain under tension, and are thus not suitable to apply in harsh environments. Polyimide-coated optical fibers have the highest shear strength and the highest ultimate strain under tension, making them the best candidate for civil infrastructure applications. Both glass fiber reinforcing polymer (GFRP) and carbon coated optical fibers are sufficiently rugged to be applied to civil infrastructure.

关键词：钢铁;光纤;应变测量;交通安全;桥梁

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The tensile properties of alloy steel 35CrMoA were measured by dynamic tension experimental apparatus,and the stress-strain curves of the material at strain rate range from 10-2/s to 103/S were obtained.The fracture appearance and metallurgical structure were observed for the recovered specimens.The influence of strain rates on mechanical properties and microstructure of the 35CrMoA steel was analyzed.Based on the experimental data of mechanical properties,the JC constitutive parameters were fitted for 35CrMoA.

关键词：力学性能;本构模型;35CrMoA钢;应变率;数值模拟

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The relative armor penetration ability of different kinds of projectiles is of general interest from both offensive and defensive viewpoints in law enforcement and military applications. This paper presents data on armor penetration of four different projectile types (all in 5.56mm NATO) on both 6.35mm thick steel plate (A36) and proprietary glass/aramid composite armor. The bullet penetrating steel plate most readily was the M855 bullet which has a steel penetrator core. This bullet had a V50 of 1992 ft/s. The second best penetrating bullet in steel plate was the jacketed lead core M193 bullet with a V50 of 2240 ft/s. The solid copper bullet had a much higher V50 in the steel plate at 2514 ft/s. The solid brass bullet was the worst penetrator in the group with a V50 of 2612 ft/s in the steel plate. The relative penetration ability was different in the composite armor. The best penetrator was once again the M855 bullet with a V50 of 1945 ft/s. However, the second best penetrator was the solid brass bullet with a V50 of 2868 ft/s. The third best penetrator was the solid copper bullet with a V50 of 2960 ft/s. The worst penetrating bullet in the composite armor was the jacketed lead core M193 bullet with a V50 of 3049 ft/s.

关键词：钢铁；合装甲；装甲；黄铜；铜

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