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Analysis of Steel Connections to Resist Progressive Collapse 预览
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作者 Yanglin Gong Chen Zhang Jian Deng 《世界工程和技术(英文)》 2019年第2期10-20,共11页
This paper presented a methodology for the analysis and design of steel connections under a double-span connection within the context of preventing progressive collapse. First, various connection models were described... This paper presented a methodology for the analysis and design of steel connections under a double-span connection within the context of preventing progressive collapse. First, various connection models were described and their pros and cons were provided. Then, the load-displacement characteristics of a component-based spring model were described. Thirdly, an experi-mental study on the behaviors of shear tab connections under tension was presented. The main sources of the deformation capacity of the shear tab connections were identified. Finally, a design example of a shear tab connection was provided to illustrate the methodology. 展开更多
关键词 STEEL STEEL Connections Shear TAB CONNECTION PROGRESSIVE COLLAPSE CONNECTION Robustness
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Oxidation behavior and lifetime prediction of three commercial alloys used in power plants at 550 ℃ in CO2 environment
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作者 Mohammad Hassan Shirani Bidabadi Yu Zheng +4 位作者 Abdul Rehman Chi Zhang Hao Chen Peggy Hou Zhi-gang Yang 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第8期898-908,共11页
The oxidation behaviors of CrMoV, F91, and 310S alloys in CO2 at 550 °C for up to 1000 h were studied by weight change measurements, scanning electron microscopy, X-ray diffraction, Raman microscopy, optical micr... The oxidation behaviors of CrMoV, F91, and 310S alloys in CO2 at 550 °C for up to 1000 h were studied by weight change measurements, scanning electron microscopy, X-ray diffraction, Raman microscopy, optical microscopy, and glow dis-charge optical emission spectroscopy. 310S showed the best oxidation resistance followed by F91 and then CrMoV. Both CrMoV and F91 formed a duplex oxide layer, consisted of Fe2O3, Fe3O4, and Fe-Cr spinel, while 310S formed NiFe2O4 spinel and Cr2O3. Carburization was only observed in F91 and 310S alloys. The rates of metal loss were evaluated for long-term applications in power plants. 展开更多
关键词 Low-alloy STEEL 9Cr STEEL STAINLESS STEEL High-temperature corrosion CARBURIZATION
Seismic behavior of thin-walled circular and stiffened square steel tubed-reinforced-concrete columns
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作者 GAN Dan ZHOU XuHong +1 位作者 LIU JiePeng LI Jiang 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第3期511-520,共10页
Steel tubed-reinforced-concrete(TRC) columns have been gradually used in the construction of high-rise buildings recently because of their high axial load-carrying capacities and excellent seismic behavior. Existing s... Steel tubed-reinforced-concrete(TRC) columns have been gradually used in the construction of high-rise buildings recently because of their high axial load-carrying capacities and excellent seismic behavior. Existing studies about their seismic behavior were focused on columns with relatively thick tubes, i.e., diameter-to-thickness/width-to-thickness(D/t) ratios were below 100,while little is known about thin-walled TRC columns, especially for square TRC columns. Considering the infilled concrete of square TRC columns is non-uniformly and non-effectively confined, accordingly, stiffened square TRC columns are usually adopted in practice. Thus, two thin-walled circular TRC columns(D/t=120) and two stiffened square ones with diagonal stiffeners in plastic hinge regions(D/t=106) were tested under a constant axial compression combined with cyclic lateral loading.Both the circular and stiffened square TRC columns had the same cross sectional area, tube thickness, reinforcing bar ratio and column height. Flexural failure occurred for all the four specimens. Test results showed the strengths of the stiffened square TRC columns were a little higher in comparison to their circular counterparts;the ductility and energy dissipation capacities were excellent for both the stiffened and circular TRC columns, indicating very good confinement was gained from the yielded steel tubes of the plastic hinge regions at the peak loads. And shear stresses(35–90 MPa) in the sheared plates showed their moderate contribution of carrying lateral loads. Finally, cross sectional capacity analysis results demonstrated the method for TRC columns is acceptable for the stiffened square TRC columns. 展开更多
关键词 STEEL tubed-reinforced-concrete COLUMN concrete filled STEEL tube composite COLUMN cyclic behavior STEEL JACKET
Parametric study of hexagonal castellated beams in post-tensioned self-centering steel connections
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作者 Hassan ABEDI SARVESTANI 《结构与土木工程前沿:英文版》 EI CSCD 2019年第5期1020-1035,共16页
The effects o f important parameters (beam reinforcing plates, initial post-tensioning, and material properties o f steel angles) on the behavior o f hexagonal castellated beams in post-tensioned self-centering (PTSC)... The effects o f important parameters (beam reinforcing plates, initial post-tensioning, and material properties o f steel angles) on the behavior o f hexagonal castellated beams in post-tensioned self-centering (PTSC) connections undergone cyclic loading up to 4% lateral drift have been investigated by finite element (FE) analysis using ABAQUS. The PTSC connection is comprised o f bolted top and bottom angles as energy dissipaters and steel strands to provide self-centering capacity. The FE analysis has also been validated against the experimental test. The new formulations derived from analytical method has been proposed to predict bending moment o f PTSC connections. The web-post buckling in hexagonal castellated beams has been identified as the dominant failure mode when excessive initial post-tensioning force is applied to reach greater bending moment resistance, so it is required to limit the highest initial post-tensioning force to prevent this failure. Furthermore, properties o f steel material has been simulated using bilinear elastoplastic modeling with 1.5% strain-hardening which has perfectly matched with the real material of steel angles. It is recommended to avoid using steel angles with high yielding strength since they lead to the yielding o f bolt shank. The necessity o f reinforcing plates to prevent beam flange from local buckling has been reaffirmed. 展开更多
关键词 finite element analysis HEXAGONAL castellated beam PARAMETRIC study POST-TENSIONED SELF-CENTERING STEEL connection STEEL moment-resisting frame
Development of and Perspective on High-Performance Nanostructured Bainitic Bearing Steel 预览
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作者 Fucheng Zhang Zhinan Yang 《工程(英文)》 2019年第2期319-328,共10页
Bearings are the most important component of nearly all mechanical equipment, as they guarantee the steady running of the equipment, which is especially important for high-end equipment such as highspeed trains and sh... Bearings are the most important component of nearly all mechanical equipment, as they guarantee the steady running of the equipment, which is especially important for high-end equipment such as highspeed trains and shield tunneling machines. Requirements regarding the quality of bearings are increasing with the rapid development in technology. A country’s bearings manufacturing level directly reflects the level of that country’s steel metallurgy and machinery manufacturing. The performance of the bearing steel is the critical factor that determines the quality of a bearing. The development of new bearing steel with higher performance is the ambition of material researchers and the expectation of the manufacturing industry. Many famous bearing manufacturing enterprises are competing to develop the new generation of bearing steel. Nanostructured bainitic bearing steel (NBBS), which is a newly developed bearing steel, not only possesses high strength and toughness, but also exhibits excellent wear resistance and rolling contact fatigue (RCF) resistance. In recent years, relevant achievements in NBBS in China have led to significant progress in this field. NBBS was first used in China to manufacture large bearings for wind turbines and heavy-duty bearings, with excellent performance. As a result, NBBS and its corresponding heat-treatment process have been included in the national and industry standards for the first time. The bearing industry considers the exploitation of NBBS to be epoch-making, and has termed this kind of bearing as the second generation of bainitic bearing. In this paper, the development of NBBS is reviewed in detail, including its advantages and disadvantages. Further research directions for NBBS are also proposed. 展开更多
关键词 NANOSTRUCTURED bainitic BEARING STEEL BEARING STEEL NANOSTRUCTURED BAINITE DEVELOPMENT
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Effect of water quenching processing parameters on the mechanical properties of a cold-rolled C-Mn-containing steel sheet 预览
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作者 ZHU Xiaodong BAO Ping +1 位作者 XUE Peng LI Wei 《宝钢技术研究:英文版》 CAS 2019年第3期19-26,共8页
Cold-rolled advanced high-strength steel sheets have become the material of choice for the automotive industry because of their unique attributes of high strength and balanced mechanical properties.High-hydrogen gas j... Cold-rolled advanced high-strength steel sheets have become the material of choice for the automotive industry because of their unique attributes of high strength and balanced mechanical properties.High-hydrogen gas jet cooling and water quenching are the most commonly used ultrafast cooling technologies for producing martensite-containing high-strength steel sheets.The water quenching technology ensures the fastest industrial cooling rate of 1 000 K/s;therefore,it has the highest potential with respect to saving alloys.In this study,the water quenching of a C-Mn-containing steel sheet is simulated during continuous annealing to investigate the effect of water quenching and tempering parameters on its mechanical properties.The results reveal that at low quenching temperatures,the strength of the steel sheet decreases as the soaking temperature increases.However,at high quenching temperatures,a high soaking temperature corresponds to increased strength after quenching,regardless of whether the material was austenitized in the single austenite zone or the inter-critical zone.Therefore,a high quenching temperature always results in a high strength and a high yield ratio after quenching.Low-temperature overaging(tempering) considerably influences the yield strength and yield ratio,and the extent of this influence is correlated with the soaking temperature. 展开更多
关键词 water quenching cold-rolled STEEL SHEET C-Mn-containing STEEL
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ICP-OES测定钢铁及合金钢中酸溶硅 预览
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作者 闫蒲根 张荣荣 夏强 《广东化工》 CAS 2019年第10期168-168,148共2页
建立了电感耦合等离子体发射光谱法(ICP-OES)测定钢铁及合金中酸溶硅的分析方法。采用稀硫酸溶解钢铁及合金钢试样、低浓度的高锰酸钾溶液氧化难溶物和低温慢溶的方式使样品溶解更加完全,减少了多离子对仪器的干扰;通过基体匹配保证了... 建立了电感耦合等离子体发射光谱法(ICP-OES)测定钢铁及合金中酸溶硅的分析方法。采用稀硫酸溶解钢铁及合金钢试样、低浓度的高锰酸钾溶液氧化难溶物和低温慢溶的方式使样品溶解更加完全,减少了多离子对仪器的干扰;通过基体匹配保证了标准溶液和样品介质的一致性。硅的方法检出限为0.03mg/L,该方法所用试剂少,减少了样品处理的复杂性,实现了钢铁及合金钢中硅的准确测定。 展开更多
关键词 电感耦合等离子体发射光谱法 钢铁 合金钢 酸溶硅 高锰酸钾
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Influence of metallurgical processing parameters on defects in cold-rolled steel sheet caused by inclusions 预览
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作者 Rui Wang Yan-ping Bao +3 位作者 Yi-hong Li Zhi-jie Yan Da-zhao Li Yan Kang 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第4期440-446,共7页
The cleanliness and defects for cold-rolled steel sheet caused by inclusions are greatly influenced by parameters in the metallurgical processing.Good control of parameters during the processing can lead to a better p... The cleanliness and defects for cold-rolled steel sheet caused by inclusions are greatly influenced by parameters in the metallurgical processing.Good control of parameters during the processing can lead to a better product.In this paper,data mining was used to explore the influence of parameters on defects in steel sheets.A decision tree model was established and it was found that the oxygen content before deoxidation,the end-point temperature of the converter,and the temperature before deoxidation had a great impact on the defects in the cold-rolled sheet that were caused by inclusions.This finding was confirmed by experiments with infrared absorption,scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and automatic inclusion analysis methods.After optimization according to results from the model and experiments,the defect rate caused by the inclusions was reduced from 0.92%to 0.38%. 展开更多
关键词 IF STEEL STEEL CLEANLINESS data MINING INCLUSIONS
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Simulation of ductile fracture initiation in steels using a stress triaxiality-shear stress coupled model 预览
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作者 Yazhi Zhu Michael D.Engelhardt Zuanfeng Pan 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第3期600-614,共15页
Micromechanics-based models provide powerful tools to predict initiation of ductile fracture in steels. A new criterion is presented herein to study the process of ductile fracture when the effects of both stress tria... Micromechanics-based models provide powerful tools to predict initiation of ductile fracture in steels. A new criterion is presented herein to study the process of ductile fracture when the effects of both stress triaxiality and shear stress on void growth and coalescence are considered. Finite-element analyses of two different kinds of steel, viz. ASTM A992 and AISI 1045, were carried out to monitor the history of stress and strain states and study the methodology for determining fracture initiation. Both the new model and void growth model (VGM) were calibrated for both kinds of steel and their accuracy for predicting fracture initiation evaluated. The results indicated that both models offer good accuracy for predicting fracture of A992 steel. However, use of the VGM leads to a significant deviation for 1045 steel, while the new model presents good performance for predicting fracture over a wide range of stress triaxiality while capturing the effect of shear stress on fracture initiation. 展开更多
关键词 DUCTILE fracture VOID growth STRESS TRIAXIALITY Shear STRESS ratio ASTM A992 STEEL AISI 1045 STEEL
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Corrosion of High Carbon Steel by Bacteria under Aerobic and Anaerobic Conditions 预览
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作者 R. C. Nwokorie C. O. Nweke +7 位作者 S. I. Umeh F. C. Ihenetu O. R. Nlemolisa U. N. Kemka C. C. Obasi C. I. Nnadi K. H. Uzoho C. C. Ejide 《材料科学与应用期刊(英文)》 2019年第3期227-242,共16页
The role of microbes in the corrosion of metals is due to the chemical activities (metabolism) associated with the microbial growth and reproduction. A lot of researches have shown that enormous loss of resources and ... The role of microbes in the corrosion of metals is due to the chemical activities (metabolism) associated with the microbial growth and reproduction. A lot of researches have shown that enormous loss of resources and even lives has been experienced in many countries of the world due to corrosion. There is therefore need to device a means of combating this menace so as to save different countries of the world including Nigeria the cost encured due to corrosion. This research has helped to determine the role of bacteria in the corrosion of high carbon steel under aerobic and anaerobic conditions was investigated using sulphate reducing bacteria and other aerobes. A sample of high carbon steel grade of chemical composition: 96% iron (Fe), 1.08% carbon (C), 0.349% silicon (Si), 0.841% manganese (Mn), 0.005% phosphorus (P) and 0.005% sulphur (S), was obtained in the form of steel plate. Eighteen (18) samples of the high carbon steel were prepared. Standard microbiological methods were used to isolate aerobic and anaerobic bacteria isolates. The microbes isolated from the soil included;aerobes (Bacillus species, Pseudomonas species) and anaerobes (Desulfovibrio species, Thiobacillus species). The role of bacteria in the corrosion of high carbon steel was estimated using the weight loss technique and the electrochemical potential measurement technique. Eighteen samples of a high carbon steel of known compositions were exposed to sulphate reducing bacteria under different environments (aerobic, anaerobic and control). The physical and chemical changes were examined and monitored on weekly basis for six weeks. It was observed that the coupons immersed in the media with sulphate reducing bacterium underwent fast activation and numerous corrosion sites were formed on the surfaces. The average corrosion rate for six weeks (42 days) period of time as determined by the weight loss method and electrochemical testing were found to be 0.0004595 mm/year, -0.712 mV in aerobic environment, 0.0005646 mm/year, -0728 mV in anaerobic en 展开更多
关键词 Bacillus SPECIES PSEUDOMONAS SPECIES DESULFOVIBRIO SPECIES THIOBACILLUS SPECIES CORROSION Steel
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Optimization of gas tungsten arc welding parameters for the dissimilar welding between AISI 304 and AISI 201 stainless steels 预览
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作者 Wichan Chuaiphan Loeshpahn Srijaroenpramong 《Defence Technology(防务技术)》 CAS CSCD 2019年第2期170-178,共9页
This present study applied gas tungsten arc welding in order to join AISI 304 and AISI 201 stainless steels.The objective was to find the optimum welding condition that gave a weld bead in accordance with DIN EN ISO 2... This present study applied gas tungsten arc welding in order to join AISI 304 and AISI 201 stainless steels.The objective was to find the optimum welding condition that gave a weld bead in accordance with DIN EN ISO 25817 quality level B,pitting corrosion potential of the weld metal of not less than that of the AISI 304 base metal and a ratio of delta-ferrite in austenite matrix of the weld metal of not lower than 3%.Such a ratio is a criterion widely accepted to protect the weld metal from solidification cracking.At the welding current of 75 A and by using pure argon as a shielding gas 0 to 8 vol.%and applying a welding speed in the range of 2e3.5mm·s^-1 was found to give a complete weld bead with an increased depthper-width ratio(promote weldability).For welding speed in the range of 3 and 3.5mmmm·s^-1(promote corrosion resistance).Increasing the welding speed in such a range decreased the amount of delta-ferrite in the austenite matrix,and increased the pitting corrosion potential of the weld metal to be 302 mVSCE.This value was still lower than the pitting corrosion potential of the AISI 304 base metal.Mixing nitrogen in argon shielding gas increased the nitrogen content in the weld.The optimum condition was found when using a welding speed of 3mm·s^-1 and mixing 1 vol.%of nitrogen in the argon shielding gas(promote weldability and corrosion resistance).Pitted areas after potentiodynamic test were observed in the austenite in which its Cr content was relatively low. 展开更多
关键词 Dissimilar WELDMENT AISI 304 STAINLESS STEEL AISI 201 STAINLESS STEEL Gas tungsten arc welding(GTAW) Nitrogen Corrosion BEHAVIOR Mechanical BEHAVIOR
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Designing a high Si reduced activation ferritic/martensitic steel for nuclear power generation by using Calphad method
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作者 Chao Liu Quanqiang Shi +4 位作者 Wei Yan Chunguang Shen Ke Yang Yiyin Shan Mingchun Zhao 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第3期266-274,共9页
A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%,... A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%, W 1.0–1.5%, Si 1.0–1.3%, V+Ta 0.30–0.45%, and Fe in balance. High Si design brings excellent corrosion resistance, while low activation is advantageous in the nuclear waste processing. The experimental results indicate that the newly designed high Si RAFM steel had full martensitic structure and uniformly distributed fine second phase particles, and exhibited excellent mechanical properties and corrosion resistance. Compared to the P91 steel, this new RAFM steel designed by Calphad method is expected to be a promising candidate used in nuclear power generation, which also provides a new and effective approach to the development of RAFM steel for nuclear application. 展开更多
关键词 Ferritic/martensitic steel ALLOY design CALPHAD method REDUCED ACTIVATION HIGH silicon
建设智慧型钢厂的分析与探究 预览
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作者 张南南 《财经与管理》 2019年第5期26-30,共5页
今日中国移步换景,产业互联网升级来得又快又急,钢铁制造企业根据发展历程、资本结构、技术条件、设备状况、企业文化的不同,都在快速寻求技术突破与产业转型,最终完成工业物联网、大数据、人工智能三维一体的智慧型钢厂建设。
关键词 钢铁 物联网 大数据 人工智能 智慧制造
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钢制低温压力容器检验及安全评估 预览
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作者 薛飞龙 《化工设计通讯》 CAS 2019年第7期219-219,268共2页
在工业生产中,钢制低温压力容器是非常重要的一部分,对于保障安全生产有很大的影响。在工业发展中,需要做好钢制低温压力容器检验和安全评估工作,从而最大程度地减少不必要的问题出现。主要对低温容器定期检验内容和钢制低温压力容器安... 在工业生产中,钢制低温压力容器是非常重要的一部分,对于保障安全生产有很大的影响。在工业发展中,需要做好钢制低温压力容器检验和安全评估工作,从而最大程度地减少不必要的问题出现。主要对低温容器定期检验内容和钢制低温压力容器安全管理的定量评价方法进行了阐述。 展开更多
关键词 钢制 低温 压力容器 检验 评价
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Enhancements of Passive Film and Pitting Resistance in Chloride Solution for 316LX Austenitic Stainless Steel After Sn Alloying
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作者 Yuan-Yuan Yang Yuan-Yuan Liu +4 位作者 Man-Lang Cheng Nian-Wei Dai Min Sun Jin Li Yi-Ming Jiang 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第1期98-106,共9页
In the present work, the electrochemical behavior and properties of the passive film of a new Sn-alloyed 316 LX austenitic stainless steel were investigated. With the increase in Sn content in 316 LX austenitic stainl... In the present work, the electrochemical behavior and properties of the passive film of a new Sn-alloyed 316 LX austenitic stainless steel were investigated. With the increase in Sn content in 316 LX austenitic stainless steel from 0 to 0.21%, the critical pitting temperature value increased from 32.6 to 38.8 °C, and the pitting potential increased from 0.252 VSCE to 0.317 VSCE. Electrochemical impedance spectroscopy results showed that the corrosion resistance of passive film rose with the increase in Sn content, indicating a more stable passive film. The Mott–Schottky measurement revealed an n-type passive film with a decreased carrier concentration on the 316 LX austenitic stainless steel surface. The Cr, Sn2+ and Sn4+(SnO, SnOHCl or SnO2) enrichments were observed in the passive layer by X-ray photoelectron spectroscopy. The enrichment of Sn and Cr in the passive film can account for the enhanced pitting resistance of 316 LX austenitic stainless steel in chloride solution. 展开更多
关键词 AUSTENITIC stainless steel SN ALLOYING PITTING Chloride solution
Effect of Prior Cold Deformation on the Stability of Retained Austenite in GCr15 Bearing Steel
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作者 Feng Wang Dong-Sheng Qian Xiao-Hui Lu 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第1期107-115,共9页
In this work, the effect of prior cold deformation on the stability of retained austenite in GCr15 bearing steel was investigated after quenching and tempering treatment. The thermal stability was evaluated by calcula... In this work, the effect of prior cold deformation on the stability of retained austenite in GCr15 bearing steel was investigated after quenching and tempering treatment. The thermal stability was evaluated by calculating thermal activation energy for decomposition of retained austenite using differential scanning calorimeter. The mechanical stability was investigated according to the strain-induced martensitic transformation behavior of retained austenite under the standard compression testing. It is found that the prior cold deformation not only accelerates the carbide dissolution during the austenitization process but also contributes to the carbon partitioning in the tempering stage due to the higher density of phase boundaries, which results in the improvement of the thermal stability of retained austenite. Due to the enhanced carbide dissolution, the higher carbon content in the prior austenite will intensify the isotropic strain of martensitic transformation. As a consequence, the film-like retained austenite is likely to form under a higher hydrostatic pressure and thus shows a higher mechanical stability. Additionally, it is noteworthy that the benefits of the prior cold deformation to the stability of retained austenite would be saturated when the cold deformation degree is larger than 40%. 展开更多
关键词 GCR15 BEARING steel Prior cold deformation RETAINED AUSTENITE stability
含铬、硅合金钢在水蒸气气氛下高温氧化行为的研究进展
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作者 高炜 孙彬 +1 位作者 王建明 张连永 《热加工工艺》 北大核心 2019年第10期6-9,14共5页
介绍了在水蒸气气氛中,含铬、硅合金钢的高温氧化动力学遵循S曲线,即第一阶段的慢速氧化、第二阶段的快速氧化和第三阶段的慢速氧化。分析了在氧化初期,具有保护性的Cr2O3/SiO2氧化层在钢表面的生成阻碍了离子的扩散,随后保护层的失效... 介绍了在水蒸气气氛中,含铬、硅合金钢的高温氧化动力学遵循S曲线,即第一阶段的慢速氧化、第二阶段的快速氧化和第三阶段的慢速氧化。分析了在氧化初期,具有保护性的Cr2O3/SiO2氧化层在钢表面的生成阻碍了离子的扩散,随后保护层的失效导致快速氧化。讨论了在含有水蒸气的高温氧化条件下,氧化皮截面通常呈三层结构。指出了通常水蒸气促使形成了含更多孔的氧化皮,多孔结构增大了氧化皮的剥离倾向。 展开更多
关键词 铬、硅 高温氧化 氧化皮 水蒸气
Effect of selective laser treatment on initiation of fatigue crack in the main part of an undercarriage drag strut
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作者 Anna BIEN Marek SZKODO +1 位作者 Jerzy DOBERSKI Bartlomiej KARPINSKI 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第3期701-714,共14页
This paper presents the results of material characterization and a fatigue test conducted for a laser-re-melted drag strut used in an aircraft landing gear. The drag strut was re-melted with a CO2 laser beam. Eight re... This paper presents the results of material characterization and a fatigue test conducted for a laser-re-melted drag strut used in an aircraft landing gear. The drag strut was re-melted with a CO2 laser beam. Eight re-melted paths were made in the form of spiral lines along the axis of the drag strut. Next, the drag strut was subjected to variable loads on a testing machine simulating loads occurring when an aircraft lands. The fatigue test showed that the laser-treated drag strut was able to withstand 1700 simulated cycles of landing. This result was 70% better than that obtained for a drag strut with no laser treatment. In order to find the reason for the increase in the number of cycles of simulated landings, tests were carried out using transmission and scanning electron microscopes, a computer microtomograph, an X-ray diffractometer, and a nanoindenter,respectively. Results of the conducted research indicated that the reasons for the increased fatigue life of the laser-treated undercarriage drag strut were both an ultra-fine cellular martensitic microstructure and compressing residual stresses generated during the laser re-melting of the surface layer of the material. 展开更多
关键词 Fatigue WEAR Laser re-melting NANOINDENTATION testing RESIDUAL stresses Steel alloy
Effect of Deep Sea Pressures on the Corrosion Behavior of X65 Steel in the Artificial Seawater
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作者 Qiu-Shi Li Shun-Zhong Luo +4 位作者 Xu-Teng Xing Jing Yuan Xin Liu Ji-Hui Wang Wen-Bin Hu 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第8期972-980,共9页
The corrosion behaviors of X65 steel in the artificial seawater at different hydrostatic pressures are investigated by potentiodynamic polarization measurements, electrochemical impedance spectroscopy measurements and... The corrosion behaviors of X65 steel in the artificial seawater at different hydrostatic pressures are investigated by potentiodynamic polarization measurements, electrochemical impedance spectroscopy measurements and weight loss measurements.The corroded morphologies and the corrosion products are also investigated by scanning electron microscopy, X-ray diffraction analysis and Raman analysis.The results show that the corrosion current increases as the hydrostatic pressure increases.The charge transfer resistance decreases as the hydrostatic pressure increases.The corrosion products are mainly composed of γ-FeOOH and Fe3O4 at the atmospheric pressure, while the main components are γ-FeOOH, Fe3O4, and γ-Fe2O3 at the high pressure.The hydrostatic pressure accelerates the corrosion of X65 steel due to its effect on the chemical and physical properties of corrosion products, including the promoted reduction of γ-FeOOH and the wider and deeper cracks on the corrosion products layer. 展开更多
关键词 X65 steel DEEP SEA pressures ELECTROCHEMICAL MEASUREMENTS Corrosion
Effect of Electric Potentials on Microstructure,Corrosion and Wear Characteristic of the Nitrided Layer Prepared on 2Cr13 Stainless Steel by Plasma Nitriding
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作者 Yang Li Shang-Zhou Zhang +4 位作者 Jian-Xun Qiu Yong-Yong He Jun-Jie Xiu Qian-Wen Ye Zhong-Li Liu 《金属学报:英文版》 SCIE EI CAS CSCD 2019年第6期733-745,共13页
Plasma nitriding is a widely used technology to enhance the surface performance and extend the service life of alloy parts.The current research mainly focuses on the influences of time,temperature,gas type and pressur... Plasma nitriding is a widely used technology to enhance the surface performance and extend the service life of alloy parts.The current research mainly focuses on the influences of time,temperature,gas type and pressure parameters on nitriding behavior,while fewer studies have been conducted on the electric potential.This paper mainly reports the effect of the electric potential on nitriding behavior.Test conditions were set using cathodic,anodic and floating potentials in a plasma nitriding furnace.2Cr13 stainless steel was nitrided at 450°C for 5h in an NH3 atmosphere.The experimental results show that the nitriding treatment can be well performed under the different electric potentials,but differences exist in microstructures,morphologies and performance results of the modified layers.The thickness and hardness values of the nitrided layer are ranked as follows:cathodic[anodic[floating potential.The anodic nitrided surface has an obvious particle deposition layer composed of nitrides and oxides.Electrochemical and tribological experiments show that the corrosion resistance and wear resistance were significantly improved after a nitriding treatment using the three electric potentials.Moreover,the floating nitriding treatment resulted in the best tribological performance and corrosion resistance. 展开更多
关键词 NITRIDING STAINLESS steel WEAR CORROSION
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