共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Blüm H. Hill H. Moll S. Weber W. Theisen 《Journal of Materials Engineering and Performance》2012,21(5):756-763
Tools used in the mineral processing industry are required to feature high wear resistance to facilitate an adequate cost
efficiency. These kinds of tools are made of composite materials based on a low-alloyed substrate material and a high-alloyed
coating. The coatings can be applied in different ways using production processes like HIP cladding, deposit welding, and
composite casting. The article is concerned with the problem of a novel and cost-effective coating alternative: sinter cladding,
using the principle of super-solidus liquid-phase sintering (SLPS). Usually SLPS represents a sintering technique, which is
used for the compaction of high-alloyed metal powders. However, no recognizable efforts were made to use the SLPS-process
for applying a PM-coating on a bulk substrate material. Sinter cladding for the first time uses SLPS to combine the process
of powder compaction with the application of a coating to a solid steel substrate into one single step. Another advantage
of the process is the possibility to produce massive bulk coatings with thicknesses exceeding 20 mm. This article is original
in the scope of question and investigation methods in terms of microstructure, hardness profiles, EDX measurements, diffusion
calculations, and computational thermodynamics. 相似文献
2.
Jun’an Wang Ying He Peng He Bangxin Zhou 《Journal of Materials Engineering and Performance》2008,17(5):780-784
Copper is an effective element to activate the sintering process of stainless steels and to enhance corrosion resistance of
the sintered specimens. Ways of introducing Cu into stainless steel powders lead to different consequence in the microstructure
and corrosion behavior of sintered Cu alloyed stainless steel. In the present work, two methods, mixing Cu with stainless
steel powder and coating stainless steel powder with Cu by electroless plating, were introduced in order to investigate their
influence on the sintered specimens. It was found that the sintered specimens from Cu-coated stainless steel powders (1-5 wt.%Cu)
produce less porous surfaces with isolated pores than the specimens from mixed powders and the former have obviously high
density and relatively even Cu distribution. Potentiodynamic polarization measurements indicate that Cu-electroless plating
of 1-5 wt.%Cu improves the corrosion resistance of sintered stainless steel due to the lowering of passivation current density. 相似文献
3.
4.
5.
The aim of the present study is to develop a Fe-based metal matrix composite (MMC) coating using high velocity oxy-fuel spraying (HVOF) process. A ledeburitic high alloyed cold work tool steel (X220CrVMo13-4) and NbC with an average size of 2 µm at different volume fractions have been considered as metal matrix and hard particles respectively. MMC coatings were deposited on austenitic stainless substrates and the coatings were subsequently densified by hot isostatic pressing (HIP) with and without encapsulation. Microstructural analysis of the as-sprayed and HIPed coatings were characterized by SEM and XRD methods. Results showed that the feedstock preparation involving fine NbC was an influencing factor on the coating deposition. A relatively homogeneous dispersion of fine NbC up to 30 vol.% in cold work tool steel matrix was possible using optimized HVOF spraying. Besides, HVOF spraying and its subsequent HIP treatment induced significant microstructural and phase changes in the MMC coatings. The study showed the potential of HVOF spraying for the development of steel based MMC coatings and its subsequent densification can be achieved by HIP process with and without encapsulation. 相似文献
6.
7.
Horst Hill Sebastian Weber Ulrich Raab Werner Theisen Lothar Wagner 《Journal of Thermal Spray Technology》2012,21(5):987-994
Corrosion and abrasive wear are two important aspects to be considered in numerous engineering applications. Looking at steels, high-chromium high-carbon tool steels are proper and cost-efficient materials. They can either be put into service as bulk materials or used as comparatively thin coatings to protect lower alloyed construction or heat treatable steels from wear and corrosion. In this study, two different corrosion resistant tool steels were used for the production of coatings and bulk material. They were processed by thermal spraying and super solidus liquid phase sintering as both processes can generally be applied to produce coatings on low alloyed substrates. Thermally sprayed (high velocity oxygen fuel) coatings were investigated in the as-processed state, which is the most commonly used condition for technical applications, and after a quenching and tempering treatment. In comparison, sintered steels were analyzed in the quenched and tempered condition only. Significant influence of alloy chemistry, processing route, and heat treatment on tribological properties was found. Experimental investigations were supported by computational thermodynamics aiming at an improvement of tribological and corrosive resistance. 相似文献
8.
9.
Development, processing and use of nitrogen alloyed high molybdenum steel X3CrNiMoN 17 13 5 Addition of 0,15% Ni to the steel X5-CrNiMo 17 13 delays the precipitation of intermetallic phases and chromium carbides. The nitrogen containing steel can be welded up to a plate thickness of 30 mm without precipitation; hot cracking has not been observed either. The weld metal corresponds to the base material with respect to ductility and corrosion resistance. It is resistant to pitting, crevice corrosion and stress corrosion cracking, in particular in mixed acids. Successful applications include textile industry (bleaching equipment, heating equipment), shipbuilding (driving shafts, exhaust gas coolers, waste gas condenser tubing), water desalination equipment, nuclear industry (evaporator for radioactive waste water, processing of radioactive waste in fluoride containing nitric acid), chemical industry (pressure container material, heat exchangers for brackish water). 相似文献
10.
利用场发射扫描电镜、透射电镜以及电化学综合测试系统对15Cr超级马氏体不锈钢(SMSS)经不同热处理工艺处理后的显微组织变化和第二相碳化物及其对该钢腐蚀行为的影响进行了研究。结果表明,试验钢经不同热处理工艺处理后组织均由板条马氏体、奥氏体以及M23C6型碳化物颗粒组成,随着回火温度的增加,试验钢中逆变奥氏体含量增加,且在650 ℃回火时达到体积分数最大值41.41%。当回火温度高于600 ℃时第二相碳化物开始析出,且650 ℃回火后碳化物数量及尺寸较600 ℃增多。点蚀电位随着回火温度的增加而降低,第二相碳化物的析出降低了试验钢的点蚀电位,促进了亚稳点蚀位置的形成,从而降低了试验钢的耐腐蚀性能。 相似文献
11.
12.
H. Huang P. Virtanen T. Tiainen Y. Ji 《Journal of Materials Engineering and Performance》1998,7(6):784-788
Elemental Ti-48Al-2Cr-2Nb powders were mechanically alloyed (MA) for 8 h and 45 h. The MA powders were then consolidated by
reactive hot isostatic pressing (HIP). The microstructure of the HIPed materials consisted of equiaxed γ-TiAl and α2-Ti3Al phases. During the high-temperature annealing of the HIPed materials, the α2-Ti3-Al phase transformed into a lamellar structure consisting of alternating laths of α2-Ti3Al and γ-TiAl. It is suggested that a high content of interstitial elements together with the microalloying elements of niobium
and/or chromium in MA powders raises α/(α + γ) transus to a higher temperature. 相似文献
13.
主要介绍并分析了在海洋环境中高频直缝焊接钢管焊缝的耐腐蚀性能、抗断裂性能(CTOD)、质量稳定性及质量保障体系;提出了提高高频直缝焊接钢管焊缝的耐腐蚀性能和质量稳定性的措施及有待深入研究的方向。分析认为:采用更低S含量的钢卷,可减少沟槽腐蚀的产生;焊缝经淬火+回火热处理工艺后,其抗HIC腐蚀性能更好。 相似文献
14.
利用光学显微镜、拉伸及冲击试验机等仪器研究了不同热处理工艺对5Cr钢组织和力学性能的影响,利用高温高压反应釜模拟腐蚀过程,并结合电化学测试对比分析了热轧态和调质态钢的耐腐蚀性能。结果表明:5Cr钢经淬火+回火处理后,组织中碳化物弥散析出,具有较高的强度和良好的塑、韧性。热轧态钢的腐蚀速率为0.188 mm/a,调质态钢为0.158 mm/a。调质态钢中作为阴极的碳化物(Fe3C)少且均匀弥散分布,组织自腐蚀电位较高,腐蚀电流密度较低,电偶腐蚀程度较浅,耐腐蚀性能较好。 相似文献
15.
为探究回火温度对EH890海洋工程用钢耐蚀性能的影响,采用X射线衍射仪、场发射扫描电镜分析了原始淬火态和不同回火温度下EH890钢的物相及微观组织,通过电化学试验研究了不同热处理状态下的腐蚀行为,并结合显微硬度、位错密度计算分析了回火温度对其腐蚀的影响规律。结果表明,EH890钢原始淬火态组织为板条贝氏体,少量粒状贝氏体及准多边形铁素体和薄膜状残留奥氏体,随着回火温度的提高,贝氏体板条不断粗化,铁素体与残留奥氏体分解转化,回火温度达到350 ℃时,贝氏体边界处开始析出弥散细小的碳化物及第二相。随回火温度的升高,试样钢的耐蚀性能呈现先上升后下降的趋势。一方面,回火处理降低了因淬火产生的高位错密度,减轻试样的腐蚀倾向;另一方面,随着回火温度的升高,弥散第二相不断从基体析出,与基体形成局部电偶作用,破坏钝化膜的完整性,降低钝化膜对基体的保护作用,降低腐蚀抗力。在两种因素的综合作用下,经350 ℃回火试样表面形成了更具保护性的钝化膜,表现出最佳的耐蚀性能。 相似文献
16.
17.
Chongfeng Sun Shengqi Xi Xiaofeng Dang Jianping Li Yongchun Guo Zhong Yang Yaping Bai 《金属学报(英文版)》2021,34(6):825-833
In this paper, microstructure characteristics and phase transitions of Fe-19 wt%Cr-9 wt%Ni nanocrystalline alloy are comprehensively studied during the mechanical alloying and hot pressing sintering processes. Corrosion resistance of the sintered Fe-19 wt%Cr-9 wt%Ni nanocrystalline alloy samples is further analyzed. During the mechanical alloying process, Fe-19 wt%Cr-9 wt%Ni nanocrystalline alloy powders mainly composed of metastable ferrite phase are obtained after mechanical alloying for 8, 16 and 24 h, respectively. In the subsequent hot pressing sintering process, the phase transitions(from ferrite to austenite) occur from 650 to 750 °C for Fe-19 wt%Cr-9 wt%Ni alloy powders milled for 24 h. When the sintering temperature is raised to 1050 °C for 1 h, the ferrite phase has transformed into austenite phase completely, and the obtained grain size of sintered Fe-19 wt%Cr-9 wt%Ni alloy is around 40 nm. Electrochemistry test of the sintered Fe-19 wt%Cr-9 wt%Ni alloy has been operated in 0.5 mol L~(-1) H_2SO_4 solution to show the corrosion resistance properties. Results show that the sintered Fe-19 wt%Cr-9 wt%Ni alloy exhibits excellent corrosion resistance, which is proved by higher self-corrosion potential, lower self-corrosion current density and larger capacitive reactance, compared with that of commercial 304 stainless steel. 相似文献
18.
19.
20.
对40Cr钢进行了表面加Ni60B粉末激光合金化处理.金相、扫描电镜、X射线衍射分析,硬度测试和磨损与盐雾腐蚀实验的结果表明:合金化层的结构为熔化区、过渡区及热影响区;熔化区显微组织为胞状一树枝状晶,热影响区为极细的隐晶马氏体;激光合金化处理后的试样产生了新相Cr23C6和Cr3C2,显微硬度Hk可达到8.6 GPa,比基体提高了近3倍;耐磨性与耐蚀性都比基体有明显提高.
相似文献