LIU Shicheng
,
Dalian Railway Insitute
,
Dalian
,
ChinaHamaguchi Yoshikazu
,
Kuwano Hisashi
,
Muroran Institute of Technology
,
Muroran
,
Japan
金属学报(英文版)
The stable ranges concerning the composition and temperature have been experimentally de- termined for the intermetallic compounds in system Fe-Cr-Mo at high-temperatures. The isothermal section of the Fe-Cr-Mo ternary phase diagram at 1250℃ and the formation re- actions for the intermetallic compounds, which are different in part from those shown in the literature, have been proposed.
关键词:
Fe-Cr-Mo system
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null
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null
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null
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null
CUI Juan
,
LIU Yazheng
,
PAN Hui
,
GAO Lifeng
钢铁研究学报(英文版)
The microsturctural transformation of austenite grain, pearlite interlamellar spacing, and lamellar cementite thickness of spring steel 60Si2MnA for railway were studied in the hotrolled and reheated states. Furthermore, the effect of microstructural characterization on its final mechanical properties was discussed. The results showed that as far as 60Si2MnA, the pearlite interlamellar spacing determined the hardness, whereas, the austenite grain determined the toughness. Compared with microstructure and mechanical properties in the hotrolled state, after reheating treatment at 950 ℃, its average grain sizes are apparently fine and the pearlite interlamellar spacing and lamellar cementite thickness coarsen to some extent, but both hardness and impact toughness increase to HRC 48 and 85 J, respectively. In the course of making spring, the optimum reheating austenitizing temperature for the 60Si2MnA steel is 950 ℃.
关键词:
austenitizing temperature;austenite grain;pearlite interlamellar spacing;hardness;toughness
M. H. Guo
,
D. C. Shao
,
Z. G Dong and J. C Yang National Key Laboratory Advanced Welding Production Technology
,
Harbin institute of Technology
,
Harbin 150001
,
China
金属学报(英文版)
Manuscript received 30 July 1999 Abstract The shielded metal arc welding (SMAW) of a manganese steel part as a crossing of railway track to a carbon steel part as the rails of the railroad is the welding of dissimilar steel. It are was known that it is not possible to the the rail of railroad directly to the cross- ing of railway track made from a steel containing about 14% of manganese (wt. ) because of so many differences between the two kinds of steels such as composition, microstructure,mechanical properties and weldability.A method was used to solve the problem by presetting an intermediate layer on each side of the joint and other special procedures were used.The result of test indicated that a good weld joint was obtained.
关键词:
high manganese steel
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null
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null
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null
MI Guofa
,
NAN Hongyan
,
LIU Yanlei
,
ZHANG Bin
,
ZHANG Hong
,
SONG Guoxiang
钢铁研究学报(英文版)
Speed increase and heavy-haul of the railway freight car are the effective measures to raise the transport ability of railway, and they have been the new trend for railway freight car development. The increase of speed and axle load will lead to the increase of wheel-rail contact stress, which will make a great change of stress distribution in the whole wheel rim. Goodier equation was employed to analyze the stress state around inclusion and cavity. In the operation of wheel-rail contact stress, stress concentration occurred in the pole of Al2O3 spherical inclusion, while it appeared on the equator of cavity. The critical inclusion sizes of 25t axle load freight car wheel at different velocities, a certain distance away from the tread, were calculated by Murakami equation. By contrast the inclusion state in cast-steel wheel and rolled-steel wheel, the inclusion character in cast-steel wheel determined that it has much more excellent crack resistance than that of rolled-steel wheel. In the meantime, in order to reduce the probability of rim crack, some suggestions were put forward.
关键词:
heavy-haul;contact stress;critical inclusion size;rim crack
Materials & Design
The present work studied the very high cycle fatigue (VHCF) behaviors of Mn-Si-Cr series Bainite/Martensite (B/M) dual phase high-strength low-alloy (HSLA) steels to ensure safe applications in railway and oil field. Four kinds of chemical compositions and seven types of B/M steels were designed and studied by ultrasonic fatigue test. The conception of apparent and intrinsic VHCF strength is addressed. Results show the effect of heat generation cannot be ignored in B/M steels in ultrasonic fatigue test, and higher is the intrinsic VHCF strength of materials, more remarkable is the negative effect of self-heating. More importantly, the VHCF property of B/M steels is less sensitive to the inclusion than that of tempered martensite steels, and the amount of retained austenite puts little effect on the VHCF property. (C) 2010 Elsevier Ltd. All rights reserved.
关键词:
high-strength steels;gigacycle fatigue;inclusion size;ultrasonic;fatigue;bearing steel;regime;life;frequency;khz
T.Senthil Kuma
,
V.Balasubramanian
材料科学技术（英文）
Medium strength aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding process for aluminium alloy is frequently TIG (tungsten inert gas) welding due to its comparatively easier applicability and better economy. In the case of single pass TIG welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The use of pulsed current parameters has been found to improve the mechanical properties of the welds compared to those of continuous current welds of this alloy due to grain refinement occurring in the fusion zone. A mathematical model has been developed to predict pitting corrosion potential of pulsed current TIG welded AA6061 aluminium alloy. Factorial experimental design has been used to optimize the experimental conditions. Analysis of variance technique has been used to find out the significant pulsed current parameters. Regression analysis has been used to develop the model. Using the developed model pitting corrosion potential values have been estimated for different combinations of pulsed current parameters and the results are analyzed in detail.
关键词:
Pulsed current
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null
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null
