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B. S. Mann 《Journal of Materials Engineering and Performance》2014,23(5):1861-1869
This article deals with water droplet erosion (WDE) behavior of high-power diode laser (HPDL) treated 17Cr4Ni PH stainless steel. After HPDL treatment, the water droplet erosion resistance (WDER) of 17Cr4Ni PH stainless steel has not improved. The main reason is the surface hardness, which has not improved after HPDL treatment though the microstructure has become much finer. On the other hand, precipitation hardening of the alloy at 490°C for 3 h has resulted in improved WDER more than twice. This is because of its increased microhardness and improved modified ultimate resilience (MUR), and formation of fine grained microstructure. The WDER has been correlated with MUR, a single mechanical property, based upon microhardness, ultimate tensile strength, and Young’s modulus. WDERs of HPDL treated, untreated, and precipitation hardened 17Cr4Ni PH stainless steel samples were determined using a WDE test facility as per ASTM G73-1978. The WDE damage mechanism, compared on the basis of MUR and scanning electron micrographs, is discussed and reported in this article. 相似文献
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B.S. Mann Vivek Arya B.K. Pant Manish Agarwal 《Journal of Materials Engineering and Performance》2009,18(7):990-998
This article deals with the high power diode laser (HPDL) surface treatment to overcome water droplet erosion of Low Pressure
Steam Turbine (LPST) moving blades used in high rating conventional, critical and super critical thermal power plants. The
materials generally used in these steam turbines are titanium alloy (Ti6Al4V), precipitate hardened stainless steel (17Cr-4Ni
PH), X20Cr13 and X10CrNiMoV1222 steels. During incubation period as well as under prolonged testing, the HPDL surface treatment
of these materials except for 17Cr-4Ni PH steel has enhanced the droplet erosion resistance significantly. This is due to
increased hardness and formation of fine-grained martensitic phase due to rapid heating and cooling rates associated with
laser treatment. The droplet erosion results of HPDL laser surface treatment of all these materials and their analysis form
the main part of the article. 相似文献
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B. S. Mann 《Journal of Materials Engineering and Performance》2013,22(12):3647-3656
This article deals with water droplet and cavitation erosion behavior of diode laser-treated X10CrNiMoV1222 stainless steel and Ti6Al4V alloy. After laser surface treatment, the water droplet and cavitation erosion resistance (WDER and CER) of these materials improved significantly. The main reason for the improvement is the increased surface hardness and formation of fine-grained microstructures after laser surface treatment. It is observed that there is a similarity in both the phenomena. The WDER and CER can be correlated with a single mechanical property based on modified ultimate resilience (MUR) provided the laser-treated layers are free from microcracks and interface defects. The CER and WDER behavior of HPDL-treated X10CrNiMoV1222 stainless steel and Ti6Al4V alloy samples using different test equipment as per ASTM G32-2003 and ASTM G73-1978, their correlation with MUR, and their damage mechanism compared on the basis of XRD analyses, optical and scanning electron micrographs are discussed and reported in this article. 相似文献
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This article deals with surface modification of twin wire arc sprayed (TWAS) and plasma ion nitro-carburized X10CrNiMoV1222
steel using high power diode laser (HPDL) to overcome water droplet erosion occurring in low pressure steam turbine (LPST)
bypass valves and LPST moving blades used in high rating conventional, critical, and super critical thermal power plants.
The materials commonly used for high rating steam turbines blading are X10CrNiMoV1222 steel and Ti6Al4V titanium alloy. The
HPDL surface treatment on TWAS coated X10CrNiMoV1222 steel as well as on plasma ion nitro-carburized steel has improved water
droplet resistance manifolds. This may be due to combination of increased hardness and toughness as well as the formation
of fine grained structure due to rapid heating and cooling rates associated with the laser surface treatment. The water droplet
erosion test results along with their damage mechanism are reported in this article. 相似文献
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B. S. Mann 《Journal of Materials Engineering and Performance》2013,22(8):2191-2200
This article deals with high power diode laser (HPDL) surface modification of twin wire arc-sprayed (TWAS) and high pressure high velocity oxy-fuel (HP-HVOF) coatings to combat solid particle erosion occurring in fossil fuel power plants. To overcome solid particle impact wear above 673 K, Cr3C2-NiCr-, Cr3C2-CoNiCrAlY-, and WC-CrC-Ni-based HVOF coatings are used. WC-CoCr-based HVOF coatings are generally used below 673 K. Twin wire arc (TWA) spraying of Tafa 140 MXC and SHS 7170 cored wires is used for a wide range of applications for a temperature up to 1073 K. Laser surface modification of high chromium stainless steels for steam valve components and LPST blades is carried out regularly. TWA spraying using SHS 7170 cored wire, HP-HVOF coating using WC-CoCr powder, Ti6Al4V alloy, and high chromium stainless steels (X20Cr13, AISI 410, X10CrNiMoV1222, 13Cr4Ni, 17Cr4Ni) were selected in the present study. Using robotically controlled parameters, HPDL surface treatments of TWAS-coated high strength X10CrNiMoV1222 stainless steel and HP-HVOF-coated AISI 410 stainless steel samples were carried out and these were compared with HPDL-treated high chromium stainless steels and titanium alloy for high energy particle impact wear (HEPIW) resistance. The HPDL surface treatment of the coatings has improved the HEPIW resistance manifold. The improvement in HPDL-treated stainless steels and titanium alloys is marginal and it is not comparable with that of HPDL-treated coatings. These coatings were also compared with “as-sprayed” coatings for fracture toughness, microhardness, microstructure, and phase analyses. The HEPIW resistance has a strong relationship with the product of fracture toughness and microhardness of the HPDL-treated HP-HVOF and TWAS SHS 7170 coatings. This development opens up a possibility of using HPDL surface treatments in specialized areas where the problem of HEPIW is very severe. The HEPIW resistance of HPDL-treated high chromium stainless steels and titanium alloys, HPDL-treated TWAS SHS 7170 and HP-HVOF coatings, and their micrographs and X-ray diffraction analysis is reported in this article. 相似文献
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B. S. Mann 《Journal of Materials Engineering and Performance》2014,23(6):1964-1972
The cast martensitic chromium nickel stainless steels such as 13Cr4Ni, 16Cr5Ni, and 17Cr4Ni PH have found wide application in hydro turbines. These steels have adequate corrosion resistance with good mechanical properties because of chromium content of more than 12%. The 13Cr4Ni stainless steel is most widely used among these steels; however, lacks silt, cavitation, and water impingement erosion resistances (SER, CER, and WIER). This article deals with characterizing 13Cr4Ni stainless steel for silt, cavitation, and water impingement erosion; and studying its improved SER, CER, and WIER behavior after high-power diode laser (HPDL) surface treatment. The WIER and CER have improved significantly after laser treatment, whereas there is a marginal improvement in SER. The main reason for improved WIER and CER is due to its increased surface hardness and formation of fine-grained microstructure after HPDL surface treatment. CER and WIER of HPDL-treated 13Cr4Ni stainless steel samples have been evaluated as per ASTM G32-2003 and ASTM G73-1978, respectively; and these were correlated with microstructure and mechanical properties such as ultimate tensile strength, modified ultimate resilience, and microhardness. The erosion damage mechanism, compared on the basis of scanning electron micrographs and mechanical properties, is discussed and reported in this article. 相似文献
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基于高速混合机桨叶所用奥氏体不锈钢的失效情况,利用激光合金化技术在奥氏体不锈钢上制备合金化强化耐磨层。利用光学显微镜、扫描电镜、X射线衍射仪、显微硬度计和光学分析仪研究合金化层的显微组织、成分、物相、横截面的硬度分布,同时利用正交试验得到激光合金化技术的优化参数。结果表明:当硬质相Al2O3的含量为70%,激光功率为2 kW,扫描速度为15 mm/s时,合金化层的显微硬度最大,达到440.8 HV0.1;所制备的合金化层无裂纹和气孔等缺陷,与基体形成冶金结合;合金化层由枝晶和枝晶间共晶组成,其相组成为奥氏体、Al2O3、Cr7C3、Mn7C3和Mn2O3;合金化层的耐磨损性能较基体的显著提高。 相似文献
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当短脉冲、高峰值功率密度 (>10 13 W /m2 )的激光辐射金属靶材时 ,就产生高温、高压等离子体 ,该等离子体受到约束层的约束时产生高强度应力波冲击金属表面并向内部传播 ,在材料表面产生应变硬化 ,称这种表面强化技术为激光冲击处理或激光喷丸。激光冲击处理可以提高材料表层硬度、强度 ,并获得比传统的喷丸技术更深的硬化层或残余压应力层 ,从而更有利于材料疲劳性能的提高 ,为研究激光冲击处理在焊后强化方面的应用 ,本文对 1.6 6mm厚的镍基高温合金GH30、1.2mm厚的奥氏体不锈钢1Cr18Ni9Ti板材焊缝进行了激光冲击处理 ,对比了激光冲击处理试件和未经激光冲击处理试件焊逢的表层显微硬度、残余应力、抗拉强度和疲劳寿命 ,发现激光冲击处理能提高GH30氩弧焊焊接接头抗拉强度 12 % ,提高 1Cr18Ni9Ti等离子焊接接头疲劳寿命30 0 %以上。 相似文献
11.
H.-J. Lipp 《工业材料与腐蚀》1975,26(11):825-831
Investigation into corrosion fatigue of ferritic stainless steels The corrosion fatigue behaviour has been studied under cyclic flexural load in air and in concentrated NaCl solutions. The materials of construction used in the rest were the steels X 20 Cr 13 and X 20 CrMo 13, and the recently developed steels Inconel X 744 and PV 520 B which are used for turbine blades. The results show that the two last mentioned steels containing, in addition to 26 and 13% Cr respectively, 6 to 7% Ni are characterized by much higher corrosion fatigue resistance (107 cycles). In view of the differences found in the results with respect to the ratio between unnotched and notched specimens, on the one hand in the group X 20 Cr 13 and X 20 CrMo 13, on the other hand in the group Inconel X 744 and PV 520 B the necessity becomes evident of using for corrosion fatigue tests notched specimens too. Nitrided surface layers may exert a considerable influence in the case of short test durations, particularly in the case of the steel X 20 CrMo 13. At test durations exceeding some 100 hours, however, the protective effect of the nitrided layers disappears. 相似文献
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借助于扫描电镜、X射线衍射仪、能谱仪和显微硬度计研究了2Cr13不锈钢激光熔覆Ni基合金及后续热处理前后的组织结构、显微硬度和耐冲蚀磨损性能。结果表明,Ni基合金激光熔覆层的显微硬度高达500~700HV,而后继热处理又进一步使熔覆层硬度提高到850~1120HV。在含有H2SO4和NaCl的砂浆水溶液中冲击速度7m·s-1、冲击角45°的条件下激光熔覆Ni基合金并经处理后可使冲蚀磨损率下降约90%。热处理使熔覆层的硬度和韧度增加。组织细化以及γNi基体中沉淀析出Fe4.5Ni18.5B6化合物被认为是覆层强化和冲蚀磨损性能改善的主要原因 相似文献
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研究了45^#钢表面镍基自熔性合金激光熔敷层的腐蚀磨损性能,并通过组织分析和硬度测试,探讨了其腐蚀磨损过程,试验表明:激光熔敷层具有良好的耐腐蚀磨损性能,比2Cr13不锈钢提高3-10倍。 相似文献
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采用正交试验对汽轮机叶片用X20Cr13钢进行了热处理工艺研究,以获得该钢的最佳热处理工艺,并在回火后以不同的速度冷却,以揭示冷却速度对钢的回火脆性的影响。结果,X20Cr13钢的最佳热处理工艺为900℃油淬或风冷,670℃回火,风冷。 相似文献
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Hot deformation behavior of X20Cr13 martensitic stainless steel was investigated by conducting hot compression tests on Gleeble–1500D thermo-mechanical simulator at the temperature ranging from 1173 to 1423 K and the strain rate ranging from 0.001 to 10 s?1. The material constants of α and n, activation energy Q and A were calculated as a function of strain by a fifth-order polynomial fit. Constitutive models incorporating deformation temperature, strain rate and strain were developed to model the hot deformation behavior of X20Cr13 martensitic stainless steel based on the Arrhenius equation. The predictable efficiency of the developed constitutive models of X20Cr13 martensitic stainless steel was analyzed by correlation coefficient and average absolute relative error which are 0.996 and 3.22%, respectively. 相似文献
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Pitting corrosion susceptibility of the heat treatable steel X20Cr13 in sodium chloride solutions For blades in steam trubines it is common to use the heat-treatable steels with 13% Cr (X20Cr13). Cracking of blades in the region of the turbine, where the steam starts to get wet, have often been referred to be caused by corrosion fatigue. The fatigue cracks sometimes start at inclusions in the material, but more often at pits caused by pitting corrosion. Pitting is brought about by chloride containing blade deposits. To examine the pitting behaviour of the steel in NaCl-solutions we measured the mixed-potential, the potentiostatic piting potential, the mass-loss and the pits per area as depending on temperature (20–80°C), pH (5–7–9), oxygen content (20 μg/kg up to saturation with oxygen) and chloride content (8×10?5 mole/l up to saturation with NaCl 5,4 mole/l). The results show that steel X20Cr13 suffers pitting corrosion because of it's low Cr content in all technical possible NaCl solutions down to a Cl content of 10?5 mole/l at the mixed potential. 相似文献
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