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简述了16Cr2Ni2A大功率机车齿轮钢的成份设计思想,研究了该钢的常规力学性能和特殊性能,建立TTT衅和CCT图,分析了钢中酸溶铝含量与奥氏晶粒度之间的关系,测定了奥氏体晶粒粗化温度和末端淬透性曲线。通过产品装车运行效果的全面调研,得出16Cr2Ni2A能满足大功率机车齿轮用钢的技术要求。 相似文献
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简要介绍我国中、重型载货汽车用齿轮钢的品种及其发展概况,并提出莱钢齿轮钢品种开发建议。 相似文献
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介绍了用大型转炉生产22MnTiBRE钢的工艺及其产品性能,通过出钢前向钢包内加入200kg/炉的钙基脱氧剂,以及喂铝线,喂加包有Ca,Ba,RE,Si,C,F的复合包芯线来净化钢液。并采用浇注时吊挂稀土棒和光亮剂,解决了大型转炉生产的钢液氧含量高,钢液分难以控制,大钢锭成分偏析大和普钢厂清理能力弱,钢材顶锻性能易保证的问题,保证了齿轮钢的淬透性带宽度,晶粒度及清洁度。表明了用转炉加精炼工艺可以生 相似文献
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介绍了圆环链用钢20Mn2钢中主要元素对钢材性能的影响,总结了安阳钢铁集团有限责任公司生产20Mn2钢的工艺。 相似文献
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Low tempered hardnesses on high speed steels which had been hardened in vacuum or atmosphere furnaces and gas quenched led to a search for a reaction occurring above 1400°F and probably initiated as a result of the slower cooling rate of the gas quench. A standard TTT evaluation was carried out on Ml, M2 high carbon, M3, and M7 high speed steels, quenching from conventional hardening temperatures, into salt baths maintained at 2000° to 1500°F. Examination of these specimens indicated the presence of a reaction occurring at all temperatures investigated but having its maximum rate at 1700° to 1800°F. The reaction involved precipitation of an MoC/Mo2C carbide at grain boundaries and within the grains, with the amount of precipitate increasing with time. The precipitation of MoC/Mo2C is directly related to the loss in tempered hardness and apparently causes this effect by 1) reducing precipitation hardening on tempering, 2) drastically lowering retained austenite contents, and 3) reducing as-quenched hardnesses. 相似文献
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介绍了高速钢轧辊的特性以及优点,并通过对西林钢铁集团轧钢总厂三轧作业区全连续棒材生产线在高速钢轧辊使用过程中,使用条件、事故处理以及使用效果等方面的总结,介绍高速钢轧辊的应用前景与效益。 相似文献
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Solidification of M2 high speed steel 总被引:5,自引:0,他引:5
R. H. Barkalow R. W. Kraft J. I. Goldstein 《Metallurgical and Materials Transactions B》1972,3(4):919-926
The freezing process in AISI type M2 high speed tool steel (6 pct W, 5 pct Mo, 4 pct Cr, 2 pct V, 0.8 pct C) was studied by
metallographic and thermal analysis techniques. Unidirectional solidification of small laboratory melts in a modified crystal
growing apparatus was employed to provide metallographic sections of known macroscopic growth direction. Also cooling curves
were obtained on 40 g specimens solidified in thimble crucibles. X-ray microradiography, electron probe scanning techniques,
and quantitative microanalysis of dendrites and interdendritic carbides were extensively used to supplement conventional metallography.
Carbon and vanadium contents of M2 were varied in order to observe the effect of an austenite and ferrite stabilizer on the
thermal analysis curves and microstructure. The nonequilibrium freezing process in M2 includes three major liquid-solid reactions:
1) Liquid → Ferrite, 1435°C; 2) Liquid + Ferrite → Austenite, 1330°C; 3) Liquid → Austenite + M6C + MC, 1240°C. These reactions account for the as-cast structure of the commercial alloy. The addition of carbon depresses
the liquidus (1) and solidus temperatures (3) and narrows the gap between the liquidus (1) and peritectic transformation (2).
This gap is eliminated at > 1.39 wt pct C, where the initial freezing reaction is the crystallization of austenite. The accompanying
microstructural change is the elimination of σ eutectoid dendrite cores. The addition of vanadium promotes ferrite formation
by strongly depressing the peritectic reaction and thus widening the gap between the liquidus and the peritectic. 相似文献
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《Canadian Metallurgical Quarterly》1999,38(5):331-335
Several years ago, in response to the trends in continuous casting technology, Paul Wurth undertook a program to develop and improve casting technology for high quality billet and bloom production. The goal of the program was to simplify the casting machine and design the equipment to be able to produce high quality billets at higher casting speeds. The approach was three-fold: first, design a new oscillation system with more control and flexibility; second, improve the spray conditions to support the higher casting speeds; and third, implement longer mold designs. 相似文献
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A philosophy for the use of strong carbide formers like niobium in high speed steels is described. It follows the concept
of independently optimizing the compositions of the matrix (for maximum secondary hardening potential) and the volume fraction
of the blocky carbides (for protection against abrasive wear). Normally, the two are interdependent through the action of
the solidification equilibria, but separate control becomes possible when the blocky carbides are formed by a strong carbide
former such as niobium. During normal ingot solidification, such strong carbide formers would produce very large primary carbides.
This can be avoided by atomization and powder metallurgical processing. In this way, a steel has been produced whose matrix
composition is similar to that of AISI M2, and whose primary carbides are all of NbC type. Its composition is 1.3C, 2W, 3Mo,
1.6V, 3.2Nb (wt pct). Because of its high stability, NbC is a much more effective obstacle to grain growth than the normal
high speed steel carbides, and this allows substantially higher austenitization temperatures to be used. Despite its leaner
composition, the Nb-alloyed steel matches the cutting performance of AISI M2, and its secondary hardening seems to be more
persistent at high temperatures. 相似文献
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J. Edwin Bridge Gunvant N. Maniar Thoni V. Philip 《Metallurgical and Materials Transactions B》1971,2(8):2209-2214
The carbides in M-50 high speed tool steel were studied in detail. The dissolution of carbides as a function of austenitizing temperature, and their precipitation as a function of tempering temperature were characterized by X-ray diffraction and microchemical analysis. The carbides in the annealed steel are M23C6, M6C, M2C, and MC. Upon austenitizing, with increasing temperatures, the carbides dissolve in the order: M23C6, metastable M2C, M6C, and MC. The residual carbides in the heat treated steel are MC and stable M2C. The solvus temperatures of M23C6 and M6C were determined. Upon tempering the hardened steel, with increasing tempering temperatures, carbides precipitate in the order: M23C6, metastable M2C, MC, and M6C. It is shown that the composition of the precipitated metastable M2C is different from that of the residual stable M2C and it varies with the tempering temperature. 相似文献
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ZHOU Candong ) LE Hairong ) FAN JunFei ) REN Sanbing ) ZHAO Shunli ) ) Baoshan Iron & Steel Co. Ltd. Shanghai China ) Advanced Technology Division Research Institute Baoshan Iron & Steel Co. Ltd. Shanghai China 《Baosteel Technical Research》2011,5(3):28-32
The microstructure of high vanadium and cobalt high speed steel(high-V/Co HSS) and the morphology of its carbides were analyzed by optical microscope(OM),scanning electron microscope(SEM),electron probe microanalysis(EPMA),X-ray power diffraction(XRD),atomic force microscopy(AFM) and single phase erosion(SPE).The results suggest that the as-sprayed high-V/Co HSS has fine equiaxed grains(about 20 μm in size),which were homogeneously distributed.The carbides have two classical morphologies:one is fine particles(about 2 μm in size) distributed along the grain boundaries and the other is needle-like one,distributed on the grain boundaries.There are MC carbides,M2C carbides,M6C carbides and Cr2WC2 carbides in the as-sprayed high-V/Co HSS samples,however,in the as-cast high-V/Co HSS,there are MC carbides and Cr2WC2 carbides only.The SPE results show that there are two types of MC carbides in the as-sprayed HSS:the sphere one and the particle-like one.The former is about 2 μm in size and the latter is less than 1 μm,dispersed inside the grains,quite different from the MC carbides in the as-cast HSS.According to the AFM results,the skeleton-like M6C carbides of the as-sprayed high-V/Co HSS are embedded in the matrix along the grain boundaries.It is found that there are sharp membrane pieces on the carbides.Some small bamboo-shoot-like MC carbides grow from the matrix and are dispersed inside the grain.Those larger MC carbides are spherical particles embedded at the grain boundary junctions. 相似文献