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Creep Rupture Strength and Microstructure of Low C-10Cr-2Mo Heat-Resisting Steels with V and Nb 总被引:1,自引:0,他引:1
T. Fujita K. Asakura T. Sawada T. Takamatsu Y. Otoguro 《Metallurgical and Materials Transactions A》1981,12(6):1071-1079
The new ferritic heat-resisting steels of 0.05C-10Cr-2Mo-0.10V-0.05Nb (Cb) composition with high creep rupture strength and
good ductility have already been reported. The optimum amounts of V and Nb that can be added to the 0.05C-10Cr-2Mo steels
and their effects on the creep rupture strength and microstructure of the steels have been studied in this experiment. The
optimum amounts of V and Nb are about 0.10 pct V and 0.05 pct Nb at 600 °C for 10,000 h, but shift to 0.18 pct V and 0.05
pct Nb at 650 °C. Nb-bearing steels are preferred to other grades on the short-time side, because NbC precipitation during
initial tempering stages delays recovery of martensite. On the long-time side, however, V-bearing steels have higher creep
rupture strength. By adding V to the steels, electron microscopic examination reveals a stable microstructure, retardation
during creep of the softening of tempered martensite, fine and uniform distribution of precipitates, and promotion of the
precipitation of Fe2Mo. 相似文献
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M. Evans 《Metallurgical and Materials Transactions A》2010,41(2):318-328
Designers of new power-generation plants are looking to make use of new and existing high-strength austenitic steels so that
these plants can operate with much higher steam and, therefore, metal temperatures. However, this article shows that the Wilshire–Scharning
methodology is incapable of producing accurate long-term-life predictions of these materials from short-term data. This article
puts forward a modification of this approach that should enable existing and newly developed austenitic stainless steels to
be brought into safe operation more cost effectively and over a shorter time span. The estimation of this model showed that
the activation energy for creep was dependent on whether the test stress was above or below the yield stress. Analysis of
the results from tests lasting only up to 5000 hours accurately predict the creep lives for stress-temperature conditions,
causing failure in 100,000 hours or more. 相似文献
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H. NICKEL P. J. ENNIS W. J. QUADAKKERS 《Mineral Processing and Extractive Metallurgy Review》2013,34(1):181-195
Abstract Creep rupture data for the 9% chromium steels Fe9CrlMoVNb (P91), Fe9CrlMolWVNb (E911) and Fe9Cr Mo2WVNb (P92) have been evaluated using the secondary creep rate as well as the stress rupture life and compared with literature data for Fe9CrlMo (P9) and 12CrlMoV. Extrapolation procedures have been carried out in order to predict the long-terms stress rupture strengths of the 9% Cr Steels. The factors affecting the reliability of the extrapolations are discussed. The 600°C/100 000 h stress rupture strength of P92 was slightly higher than that of E911 based on data of up to 30 000h duration. The effect of oxidation on rupture life was assessed; for components of wall thickness below about 6 mm, the loss of load-bearing cross-section due to oxidation should be taken into account for service life prediction. 相似文献
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研究了预处理温度对00Cr12Ni10MoTi马氏体不锈钢强度的影响。研究结果表明:在较低预处理温度下,通过非扩散α′→γ逆转变形成的奥氏体遗传了原始的锻态组织。而在950℃以上温度预处理则形成再结晶的奥氏体。由于最终750℃固溶处理遗传了预处理组织,因此预处理对钢的强度有明显的影响。材料在低于850℃预处理时最终组织中残余奥氏体量较高,不利于提高强度。850℃预处理出现峰值强度,继续提高预处理温度,强度又下降。由于950℃以上预处理形成再结晶的奥氏体,使得最终热处理后的强度稳定在较低的水平。 相似文献
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MA Zheng-huan ZHAO Xiang-juan GE Chang-sheng DING Tie-suo LI Jun XIAO Xue-shan 《钢铁研究学报(英文版)》2011,18(9):41-46
A new family of resource-saving, high chromium and manganese super duplex stainless steels (DSSs), with a composition in mass percent, % of Cr 0.29, Mn 0.12, Ni 2.0, Mo 1.0, and N 0.51-0.68, has been developed by examining the effect of N on the microstructure, mechanical properties and corrosion properties. The results show that these alloys have a balanced ferrite-austenite relation. The austenite volume fraction decreases with the solution treatment temperature, but it increases with an increase in N content. The increases in nitrogen enhance the ultimate tensile strength (UTS) and reduce the ductility of the material slightly. The pitting corrosion potential increases first and then decreases with an increase in nitrogen content when the amount of N arrives to 0.68%. The yield stress and ultimate tensile strength of solution-treated samples were more than 680 and 900 MPa, the elongation of experimental alloys are higher than 30%, respectively, what is more, the pitting potentials were beyond 1100 mV. 相似文献
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Assessment of Creep Deformation,Damage, and Rupture Life of 304HCu Austenitic Stainless Steel Under Multiaxial State of Stress 总被引:1,自引:0,他引:1
K. C. Sahoo Sunil Goyal P. Parameswaran S. Ravi K. Laha 《Metallurgical and Materials Transactions A》2018,49(3):881-898
The role of the multiaxial state of stress on creep deformation and rupture behavior of 304HCu austenitic stainless steel was assessed by performing creep rupture tests on both smooth and notched specimens of the steel. The multiaxial state of stress was introduced by incorporating circumferential U-notches of different root radii ranging from 0.25 to 5.00 mm on the smooth specimens of the steel. Creep tests were carried out at 973 K over the stress range of 140 to 220 MPa. In the presence of notch, the creep rupture strength of the steel was found to increase with the associated decrease in rupture ductility. Over the investigated stress range and notch sharpness, the strengthening was found to increase drastically with notch sharpness and tended toward saturation. The fractographic studies revealed the mixed mode of failure consisting of transgranular dimples and intergranular creep cavitation for shallow notches, whereas the failure was predominantly intergranular for relatively sharper notches. Detailed finite element analysis of stress distribution across the notch throat plane on creep exposure was carried out to assess the creep failure of the material in the presence of notch. The reduction in von-Mises stress across the notch throat plane, which was greater for sharper notches, increased the creep rupture strength of the material. The variation in fracture behavior of the material in the presence of notch was elucidated based on the von-Mises, maximum principal, and hydrostatic stresses. Electron backscatter diffraction analysis of creep strain distribution across the notch revealed localized creep straining at the notch root for sharper notches. A master curve for predicting creep rupture life under the multiaxial state of stress was generated considering the representative stress having contributions from both the von-Mises and principal stress components of the stress field in the notch throat plane. Rupture ductility was also predicted based on the multiaxial state of stress. 相似文献
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《Canadian Metallurgical Quarterly》2013,52(3):357-364
AbstractThe effects of intergranular precipitation (size of precipitates) and phosphorus grain boundary segregation on fracture and corrosion behaviours of the 18Cr-12Ni steel were investigated. In the investigation, techniques of light microscopy, SEM, TEM, AES, EDX, electron diffraction, and the Huey test were used. A good correlation was found between the average size of intergranular particles and the portion of intergranular fracture for samples impact loaded at 173 K. The equilibrium values of phosphorus grain boundary concentration showed the close correlation with the values of weight loss (penetration depth) measured during the Huey test. 相似文献
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Type 347 austenitic stainless steel (18Cr-12Ni-Nb) was alloyed with copper (3 wt pct), boron (0.01 to 0.06 wt pct), and cerium
(0.01 wt pct) with an aim to increase the creep rupture strength of the steel through the improved deformation and cavitation
resistance. Short-term creep rupture strength was found to increase with the addition of copper in the 347 steel, but the
long-term strength was inferior. Extensive creep cavitation deprived the steel of the beneficial effect of creep deformation
resistance induced by nano-size copper particles. Boron and cerium additions in the copper-containing steel increased its
creep rupture strength and ductility, which were more for higher boron content. Creep deformation, grain boundary sliding,
and creep cavity nucleation and growth in the steel were found to be suppressed by microalloying the copper-containing steel
with boron and cerium, and the suppression was more for higher boron content. An auger electron spectroscopic study revealed
the segregation of boron instead of sulfur on the cavity surface of the boron- and cerium-microalloyed steel. Cerium acted
as a scavenger for soluble sulfur in the steels through the precipitation of cerium sulfide (CeS). This inhibited the segregation
of sulfur and facilitated the segregation of boron on cavity surface. Boron segregation on the nucleated cavity surface reduced
its growth rate. Microalloying the copper-containing 347 steel with boron and cerium thus enabled to use the full extent of
creep deformation resistance rendered by copper nano-size particle by increase in creep rupture strength and ductility. 相似文献
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0.03C-4.5Si-14Cr-8Ni双相铸造不锈钢的组织和耐蚀性 总被引:1,自引:0,他引:1
本文对所设计的0.03C-4.5Si-14Cr-8Ni(DLNGG)双相铸造不锈钢进行了组织和耐蚀性研究。试验结果表明,该钢经1050℃1.5h水冷固溶处理后,得到铁素体-奥氏体双相组织,在浓硫酸介质中有良好的耐蚀性能。 相似文献
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P. Behjati A. Kermanpur A. Najafizadeh H. Samaei Baghbadorani L. P. Karjalainen J. -G. Jung Y. -K. Lee 《Metallurgical and Materials Transactions A》2014,45(13):6317-6328
Martensite reversion treatment was utilized to obtain ultrafine grain size in Fe-18Cr-12Mn-N stainless steels containing 0 to 0.44 wt pct N. This was achieved by cold rolling to 80 pct reduction followed by reversion annealing at temperatures between 973 K and 1173 K (700 °C and 900 °C) for 1 to 104 seconds. The microstructural evolution was characterized using both transmission and scanning electron microscopes, and mechanical properties were evaluated using hardness and tensile tests. The steel without nitrogen had a duplex ferritic-austenitic structure and the grain size refinement remained inefficient. The finest austenitic microstructure was achieved in the steels with 0.25 and 0.36 wt pct N following annealing at 1173 K (900 °C) for 100 seconds, resulting in average grain sizes of about 0.240 ± 0.117 and 0.217 ± 0.73 µm, respectively. Nano-size Cr2N precipitates observed in the microstructure were responsible for retarding the grain growth. The reversion mechanism was found to be diffusion controlled in the N-free steel and shear controlled in the N-containing steels. Due to a low fraction of strain-induced martensite in cold rolled condition, the 0.44 wt pct N steel displayed relatively non-uniform, micron-scale grain structure after the same reversion treatment, but it still exhibited superior mechanical properties with a yield strength of 1324 MPa, tensile strength of 1467 MPa, and total elongation of 17 pct. While the high yield strength can be attributed to strengthening by nitrogen alloying, dislocation hardening, and slight grain refinement, the moderate strain-induced martensitic transformation taking place during tensile straining was responsible for enhancement in tensile strength and elongation. 相似文献
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Joonoh Moon Tae-Ho Lee Seong-Jun Park Jae-il Jang Min-Ho Jang Heon-Young Ha Byoungchul Hwang 《Metallurgical and Materials Transactions A》2013,44(7):3069-3076
The tensile deformation behavior and phase transformation in the weld coarse-grained heat-affected zone (CGHAZ) of a metastable high-nitrogen austenitic stainless steel was explored through tensile tests, nanoindentation experiments, and transmission electron microscopy analysis. True stress–strain response during tensile test was found to be seriously affected by δ-ferrite fraction, which depends on peak temperature of the CGHAZs. The strain-induced martensitic transformation (SIMT) occurred in base steel, whereas the SIMT disappeared and deformation twinning occurred predominantly in the CGHAZs. The relationship among true stress–strain response, nanoindentation hardness, and deformed microstructures was carefully investigated and discussed in terms of changes of stacking fault energy. 相似文献
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奥氏体不锈钢较低的屈服强度限制了它在结构件中的使用。采用形变和相逆转变方法分别制备出了高屈服强度的奥氏体不锈钢。利用X射线衍射仪、光学显微镜、扫描电子显微镜、透射电子显微镜、电子背散射衍射技术和万能试验机分别对奥氏体钢进行组织表征和力学性能测试,结果表明粗大的奥氏体晶粒在形变过程中形成位错、剪切带、应变诱导马氏体等组织,相逆转变方法获得了超细的无缺陷等轴奥氏体晶粒。形变强化和细晶强化均能明显提高奥氏体不锈钢屈服强度(280 MPa提升至550 MPa)的同时保持较好的塑性(伸长率46%和55%)。 相似文献
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通过加热温度和保温时间与钢中铁素体(α相)含量和形态的关系,研究了尿素设备用00Cr18Ni10和00Cr17Ni14Mo2超低碳不锈钢的热加工性能,制定了热轧中板合适的加热制度;根据固溶处理温度与耐蚀性能的关系,确定了适宜的热处理工艺。结果表明,这两种钢的国产材与进口材的耐蚀性能基本相当。 相似文献
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K.A. Nibur B.P. Somerday C. San Marchi D.K. Balch 《Metallurgical and Materials Transactions A》2010,41(13):3348-3357
The objective of this study was to evaluate the effects of hydrogen on the fracture toughness and fracture mechanisms for
the nitrogen-strengthened, austenitic stainless steel 22Cr-13Ni-5Mn, an alloy with potential value in high-pressure hydrogen
containment components. The fracture initiation toughness and crack-growth resistance were measured before and after thermal
precharging with hydrogen and as a function of crack-growth orientation and material strength. The effects of crack-growth
orientation and material strength dominated over the effect of hydrogen exposure. The former two variables caused changes
in fracture initiation toughness of up to 400 pct, while dissolved hydrogen resulted in only modest decreases in fracture
initiation toughness of 20 to 40 pct. Coarse Z-phase (CrNbN) particles aligned in bands governed the measured fracture toughness and observed fracture mode. Fracture progressed
by void nucleation and growth in the Z-phase bands, forming microcracks that ultimately linked through the remaining austenite matrix. Crack-growth orientation,
material strength, and hydrogen exposure affected the nucleation and growth of voids in the Z-phase bands and the subsequent linking of microcracks. Control or elimination of the coarse, banded Z phase would likely enhance the fracture resistance of this alloy. 相似文献
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The effects of carbon on general and pitting corrosion behaviour of Fe‐18Cr‐10Mn‐(0.33~0.44)N‐(0~0.38)C alloys were investigated using potentiodynamic tests. Carbon made the nitrogen‐bearing alloys inert and thus promoted general corrosion resistance. These results were supported by experimental findings, such as elevated corrosion potential, reduced active dissolution rate, lowered passive potential and accelerated hydrogen evolution rate in sulphuric acid solution. The resistance to pitting corrosion in chloride solution was also enhanced by the addition of carbon, which was attributed to the improvement of the stability of the passive film. XPS analysis revealed that the cationic fraction of chromium in the passive film was increased and hence the protection ability of the film was improved by the carbon addition. 相似文献