超临界汽轮机用1Cr11MoNiW1VNbN不锈钢组织和性能的研究

以超临界汽轮机用1Cr11MoNiW1VNbN不锈钢为研究对象,研究了热处理工艺对其组织和力学性能的影响.研究表明:1Cr11MoNiW1VNbN不锈钢经几种工艺热处理后的组织全部是板条马氏体组织,随着淬火温度的升高,晶粒度逐渐变大;抗拉强度随回火温度的升高而下降,且在660℃以后下降速度快速增加,材料塑性随回火温度的升高而升高,1050℃和1100℃淬火的试样无论是强度还是塑性都比较高;其拉伸断裂时均为脆性断裂,但在同一淬火温度的条件下,随着回火温度的升高,断口的韧性断裂特性逐渐趋于明显;1Cr11MoNiW1VNbN不锈钢硬度随回火温度的升高先下降后升高,在回火温度为695℃处最低.     

1Cr11MoNiW1VNbN钢螺栓裂纹分析

1Cr11MoNiW1VNbN钢螺栓毛坯料调质后发现表面存在纵向裂纹。通过对毛坯料裂纹进行宏观观察、断口宏微观分析、能谱测试、金相分析以及理化检验等,最终确定了毛坯料的开裂原因。结果表明:裂纹内存在氧化层,裂纹两侧脱碳明显且裂纹末梢不耦合,因此毛坯料上的裂纹应是轧制过程中折叠缺陷导致的原始裂纹。     

1Cr11MoNiW1VNbN不锈钢不同热处理工艺对力学性能影响

本文研究了1Cr11MoNiW1VNbN不锈钢不同热处理后的力学性能,结果表明,它的强度随回火温度升高而下降,且在660 ℃以下快速下降,材料塑性随回火温度的升高而升高,1050 ℃的试样强度和塑性都比较高.冲击功随回火温度升高先上升后下降再升高,在695 ℃处回火有一个最低点.综合分析得到最佳热处理制度为:1050 ℃淬火,660 ℃回火.     

2Cr11Mo1VNbN围带滚弯断裂分析

通过对2Cr11Mo1VNbN围带滚弯断裂工艺过程、断裂断口化学成分、力学性能、宏观形貌及微观组织进行分析,找出2Cr11Mo1VNbN围带滚弯断裂的原因,并研究出预防2Cr11Mo1VNbN围带滚弯发生断裂的工艺。     

1Cr11MoNiW1VNbN钢堆焊司太立合金工艺

1Cr11MoNiW1VNbN钢为马氏体不锈钢,焊接时易出现冷裂纹和再热裂纹。司太立合金为耐磨硬质合金,强度和硬度高,塑韧性差,焊接性差,因此堆焊需要选择合适的焊材焊接过渡层,制定严格的焊接和热处理工艺,避免焊接裂纹的产生,满足使用要求。选择镍基合金作为过渡层,并严格控制工艺参数,获得理想的堆焊层,验证了堆焊工艺的可行性,实现了指导工业生产的目的。     

2Cr12Ni4Mo3VNbN新型叶片钢高频淬火后的显微组织与疲劳性能

为提高2Cr12Ni4Mo3VNbN马氏体不锈钢叶片的疲劳性能,对调质处理后的叶片刃口区进行了高频淬火处理,研究了高频淬火前后2Cr12Ni4Mo3VNbN钢的显微组织、残余应力分布和疲劳性能。结果表明:2Cr12Ni4Mo3VNbN钢高频淬火后显微组织中的原奥氏体晶粒和马氏体板条束都得到细化,没有明显的析出物,而未高频淬火的马氏体有较多窄条状M3C析出。2Cr12Ni4Mo3VNbN叶片高频淬火区表层层深0.1 mm以内主要为压应力,应力值约在-450 MPa^-20 MPa之间,且随层深增加而减小。高频淬火态2Cr12Ni4Mo3VNbN钢的疲劳裂纹扩展门槛值为6.75 MPa·m^1/2,高于未高频淬火态下的4.73 MPa·m^1/2,并且高频淬火态2Cr12Ni4Mo3VNbN钢中的疲劳裂纹扩展速率低于未高频淬火态。这表明,高频淬火处理提高了2Cr12Ni4Mo3VNbN马氏体不锈钢的疲劳裂纹扩展抗力和疲劳裂纹扩展寿命。     

1Cr12Ni2W1Mo1V钢等离子淬火后的疲劳行为

采用模拟点蚀坑试样,研究了等离子淬火不同温度回火1Cr12Ni2W1Mo1V钢疲劳裂纹萌生和扩展行为.结果表明,由于等离子淬火的晶粒细化作用和在试样表面引入的残余压应力,提高了末级叶片用钢裂纹萌生抗力.比较两种回火温度试样试验结果,250 ℃回火试样裂纹萌生和扩展抗力均优于540 ℃回火试样.本研究结果为选择合适的热处理工艺提供了理论依据.     

（Ti，Al）N涂层对不锈钢基材疲劳性能的影响

采用多弧离子镀技术在马氏体不锈钢1Cr11Ni2W2MoV表面分别沉积Ti70Al30N及梯度（Ti,Al）N涂层.涂层试样的疲劳试验在旋转弯曲疲劳实验机上室温下进行,研究了涂层试样与基体材料的疲劳强度、寿命及疲劳断裂机理.结果表明：施加Ti70Al30N涂层样品与梯度（Ti,Al）N涂层样品的条件疲劳极限较1Cr11Ni2W2MoV不锈钢基材的疲劳极限分别提高约7%及8%;施加涂层提高不锈钢基材疲劳寿命的原因主要在于Ti70Al30N涂层与梯度（Ti,Al）N涂层中的残余压应力作为滑移变形的阻力可阻碍疲劳裂纹的萌生与扩展.     

压应力导致不锈钢的应力腐蚀

用表面残余压应力试样,U型弯曲试样(用其压缩区)和WOL恒位移缺口压缩试样对1Cr18Ni9不锈钢在沸腾MgCl_2溶液中进行了压应力条件下的应力腐蚀试验。结果表明,三种试样分别经110h,73—100h以及262—324h后都观察到了由压应力所产生的应力腐蚀裂纹,并获得了具有岩层状特征的准解理脆性断口。这和拉应力腐蚀时获得的解理断口明显不同。压应力条件下应力腐蚀裂纹的孕育期比拉应力要高1—2个数量级,而且裂纹扩展缓慢,加上裂纹不能张开而难于辨认,故当试样中同时存在拉应力时将不会观察到压应力所产生的应力腐蚀裂纹。     

STRESS CORROSION CRACKING OF AUSTENITIC STAINLESS STEEL UNDER COMPRESSIVE STRESS

用表面残余压应力试样,U型弯曲试样(用其压缩区)和WOL恒位移缺口压缩试样对1Cr18Ni9不锈钢在沸腾MgCl_2溶液中进行了压应力条件下的应力腐蚀试验。结果表明,三种试样分别经110h,73—100h以及262—324h后都观察到了由压应力所产生的应力腐蚀裂纹,并获得了具有岩层状特征的准解理脆性断口。这和拉应力腐蚀时获得的解理断口明显不同。 压应力条件下应力腐蚀裂纹的孕育期比拉应力要高1—2个数量级,而且裂纹扩展缓慢,加上裂纹不能张开而难于辨认,故当试样中同时存在拉应力时将不会观察到压应力所产生的应力腐蚀裂纹。     

Electrical conductivity of 1 : 1 and 2 : 1 clay minerals

The A.C. impedance plots were used as tools to analyze the electrical response of two varieties of Tunisian halloysite 1: 1 and illitic samples 2: 1 as a function of frequency at different temperatures (80–800°C). The real and imaginary parts of the complex impedance trace semicircles in the complex plane. Except for the illite, It-1, the second sample analyzed in this study, these plots give evidence for the presence of both bulk and grain boundary effect, above 600°C onwards. The bulk resistance of the materials decreases with the rise in temperature. Impedance Spectroscopy data reveal a non-Debye type of dielectric relaxation. The Nyquist plots show the negative temperature coefficient of resistance of both pure Tunisian illite and halloysite samples. The results of bulk electrical conductivity and its activation energy are presented for the two mineral clay samples. For illite It-1, the activation energy values estimated from the AC conductivity pattern and modulus pattern are very similar and suggest a possibility of a long-range mobility of charge carriers (ions) via hopping mechanism of electrical transport processes at higher temperature. On the other hand, for the halloysite sample provided from kasserine, (Ha-Kass), the modulus analysis admit that the electrical transport processes of the material are very likely of electronic nature. Relaxation frequencies follow an Arrhenius behavior with the activation energy values not comparable to those found for the electrical conductivity.     

20Cr1Mo1V1钢的分级时效工艺研究

研究了 2 0Cr1Mo1V1钢的强韧化工艺。所优化出的分级时效工艺能使其强度和韧性达到质保书的要求。     

A contribution to the crystallochemistry of ternary 1:1:1 and 1:1:2 rare earth intermetallic phases with Pb and Pd

The ternary alloys of the rare earths with lead and palladium were studied for the stoichiometric ratios 1:1:1 and 1:1:2 with respect to the structure of these alloys and their existence field. RPbPd (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb) compounds have a hexagonal structure, hP9 Fe₂P type, while RPbPd₂ (R = Pr, Sm, Gd, Tb, Dy, Ho, Er, Yb) alloys have the cubic AlCu₂Mn-type structure (cF16, BiF₃ superstructure).     

Stabilization of extended stacking faults by {1 1 1}/{1 1 2} twin junction interactions

Extended stacking faults, with lengths of up to 10 nm, that join {1 1 1}/{1 1 2} twin-boundary junctions were observed by high-resolution transmission electron microscopy (HRTEM) in gold thin films. Circuit analysis shows that these defects possess a Burgers vector of 1/3〈1 1 1〉. In order to explain the generation of these extended defects, we consider the behavior of 1/3〈1 1 1〉 dislocations at {1 1 1}- and {1 1 2}-type twin boundaries and near {1 1 1}/{1 1 2} twin-boundary junctions using HRTEM observations and theoretical modeling. By establishing the interaction forces that lead to this defect configuration, our analysis shows that the relief of intrinsic strain at the junction corners, which results from the incompatibility of the translation states at the intersecting boundaries, is sufficient to stabilize the stacking fault extension. Because grain–boundary junctions possess intrinsic strain fields whenever they join boundaries with incompatible translation states, similar mechanisms for stacking fault emission may arise between other closely spaced grain–boundary junctions.     

有机阴离子转运多肽1B1的遗传药理学进展

人体存在多种类型的药物转运体,对于药物的吸收、分布和排泄起重要作用。参与药物跨膜转运的转运体功能受影响,将可能导致诸多临床药物的疗效、毒副作用甚至药物相互作用的发生。在各种影响因素中,遗传多态性所起的作用最为重要,可导致基因表达和蛋白功能发生改变。目前,阐明转运体基因的多态性以及基因型与表型之间的相互关系已成为应用遗传信息指导临床个体化用药的必要步骤。本文就肝脏有机阴离子转运多肽1B1(OATP1B1[OATP-C],编码基因SLCO1B1)基因多态性对药代动力学和药效动力学的影响及其临床意义等方面的进展作一综述。     

Variability in Co2 Oxidation Resistance of 2 1/4 Cr 1 Mo and 1 Cr 1/2 Mo Steels

Abstract

Oxidation tests in CO₂ atmospheres on nominally identical casts of low alloy steels have revealed wide variation in oxidation resistance. A study has been made of the influence of chemical composition, mechanical and thermal treatment, and remelting on the CO₂ oxidation behaviour of steels of the 21/4 Cr 1 Mo and 1 Cr 1/2 Mo type.

Statistical analyses of CO₂ oxidation results have shown a strong positive correlation of oxidation rate with sulphur content in certain instances, but a number of anomalies have been found. A similar relationship has been obtained between ‘MnS’ content and oxidation rate by area count studies of the inclusions in a range of 2 1/4 Cr 1 Mo steels. These have also indicated a possible effect of ‘MnS’ particle size and particle size distribution which could account for some of the anomalous results obtained in the statistical work. Conventional solid state heat treatments appear to have no significant effect on the oxidation behaviour of 2 1/2 Cr 1 Mo and while remelting in argon did not generally improve oxidation behaviour, remelting in vacuo followed by forging and rolling resulted in a material of high oxidation resistance.     

1(1/4)Cr—(1/2)Mo耐热钢焊接工艺试验

本文介绍美国引进的1(1/4)Cr—(1/2)Mo耐热钢匹配以国产焊丝、焊条的工艺评定试验及现场工程应用。