600℃超超临界电站锅炉过热器及再热器管道用先进奥氏体耐热钢的研究与发展

介绍了目前国内600℃超超临界电站在世界燃煤火力电站改进背景下的发展及其对高温材料的需求。通过对电站锅炉中最关键部件——过热器及再热器管道主要使用的三种新型奥氏体耐热钢的成分、组织及性能进行比较分析,讨论了当前在超超临界电站中正大量使用的奥氏体耐热钢的特点及其研究状况。随着电站蒸汽参数值的提高,为满足对材料高温性能的要求,提出研究新型奥氏体耐热钢的发展方向。     

超超临界火电机组用关键锅炉钢性能分析

对T/P92、T/P122、S30432(Super 304H)、S31042(HR3C)、9Cr3W3Co等先进锅炉钢的性能进行了综合评述,对比分析了这几种钢管及其焊接接头的持久强度、抗腐蚀性能和常规力学性能数据,采用等温线法和Larson-Miller法外推了这些锅炉钢的10万h持久强度,探讨了这几种钢管许用应力的设定及在工程设计和应用的问题。     

超超临界电站锅炉用耐热钢的水蒸汽氧化行为

燃煤火力发电站利用高温高压蒸汽为工质进行发电。随着火力发电的水蒸汽参数提高到超超临界,水蒸汽氧化问题变得尤其突出。当前超(超)临界火电站锅炉用耐热钢主要有低合金耐热钢、9%Cr型马氏体耐热钢和18Cr-8Ni型奥氏体耐热钢。综述了上述三类耐热钢的蒸汽氧化行为,着重介绍了动力学规律和氧化皮结构特点以及提高抗蒸汽氧化性能的方法。并对这三类材料使用中会出现的蒸汽氧化问题提出了对策。     

抗蠕变耐热镁合金的发展现状

讨论了镁舍金抗高温蠕变机理和提高镁合金抗高温蠕变的途径,重点介绍了Mg-Al系、Mg-Zn系和Mg-RE系耐热铸造镁合金的研究现状;对高性能耐热镁合金的发展趋势提出了一些见解,认为应该进一步优化合金元素,以解决铸造镁舍金在耐高温、抗蠕变等方面存在的问题。     

Precipitation Reactions during the Heat Treatment of Ferritic Steels

The precipitation reactions in two ferritic steels, 9Cr-1Mo-V-Nb and 12Cr-1Mo-V-W, were studied. Analytical electron microscopy, optical microscopy, electrolytic extractions, and hardness measurements were used to determine the types, amounts, and effects of precipitates formed as a function of the heat treatment. The effect of variations in the austenitizing treatment was ascertained. In addition to variations in the austenitizing time and temperature, different cooling rates after austenitization were also used. Air cooling after austenitization (normalization) resulted in little precipitation in both alloys. Precipitation in the 12Cr-1Mo-V-W alloy after furnace cooling was found in all cases examined. Under certain conditions precipitation was also found after furnace cooling the 9Cr-1Mo-V-Nb alloy. However, when compared to the amount of precipitate in the fully tempered state, the 9Cr-1Mo-V-Nb showed a much greater variation in the degree of precipitation following furnace cooling. In addition, the matrix microstructure of the 9Cr-1Mo-V-Nb alloy was very sensitive to cooling rate. The precipitation reactions during tempering after a normalizing treatment were followed as a function of tempering treatment. Tempering temperatures were varied from 400 to 780 °C. The carbide precipitation was essentially complete after one hour at 650 °C for both alloys. Analytical microscopy was used to identify the precipitates. In the 9Cr-1Mo-V-Nb alloy, a combination of chromium-rich M₂₃C₆ and vanadium-niobium-rich MC carbides was found. The carbides in the 12Cr-1Mo-V-W alloy were identified as chromium-rich M₂₃C₆ and vanadium-rich MC. The results give an indication of the sensitivity of these alloys to heat treatment variations. This paper is based on a presentation made at the “Peter G. Winchell Symposium on Tempering of Steel” held at the Louisville Meeting of The Metallurgical Society of AIME, October 12-13, 1981, under the sponsorship of the TMS-AIME Ferrous Metallurgy and Heat Treatment Committees.     

磁场热处理铁素体钢或珠光体钢时的传热现象

观察、分析了在磁场热处理条件下磁场对传热的作用，研究结果表明：在磁场热处理铁素体钢或珠光体钢时，磁场能够显地促进钢的传导热、加速钢材折冷却、细化铁素体晶粒，磁场还能促进钢材的均匀冷却，缩小钢材表面与心部动却速度的差异。     

新型铁素体耐热钢抗氧化性研究

本文对一种新型铁素体耐热钢进行了抗氧化实验研究和实际使用条件下的模拟实验研究，证明了实验钢具有优异的抗氧化性。并可以作为在１０００￣１０５０℃空气介质条件下长期服役的构件。     

Mechanical Performance of Ferritic Martensitic Steels for High Dose Applications in Advanced Nuclear Reactors

Ferritic/martensitic (F/M) steels are considered for core applications and pressure vessels in Generation IV reactors as well as first walls and blankets for fusion reactors. There are significant scientific data on testing and industrial experience in making this class of alloys worldwide. This experience makes F/M steels an attractive candidate. In this article, tensile behavior, fracture toughness and impact property, and creep behavior of the F/M steels under neutron irradiations to high doses with a focus on high Cr content (8 to 12) are reviewed. Tensile properties are very sensitive to irradiation temperature. Increase in yield and tensile strength (hardening) is accompanied with a loss of ductility and starts at very low doses under irradiation. The degradation of mechanical properties is most pronounced at <0.3T _M (T _M is melting temperature) and up to 10 dpa (displacement per atom). Ferritic/martensitic steels exhibit a high fracture toughness after irradiation at all temperatures even below 673 K (400 °C), except when tested at room temperature after irradiations below 673 K (400 °C), which shows a significant reduction in fracture toughness. Creep studies showed that for the range of expected stresses in a reactor environment, the stress exponent is expected to be approximately one and the steady state creep rate in the absence of swelling is usually better than austenitic stainless steels both in terms of the creep rate and the temperature sensitivity of creep. In short, F/M steels show excellent promise for high dose applications in nuclear reactors.     

超临界超超临界锅炉管品种的开发现状

本文介绍了超临界、超超临界锅炉管的开发背景和品种发展现状,其中包括铁素体锅炉管、新型奥氏体不锈钢锅炉管、镍基合金锅炉管、加w的2.25%Cr(T/P23)钢管、改进型9% Cr-1% Mo(T/P91)钢管、加W的9% Cr( T/P92)钢管、双金属复合管等锅炉用管的主要化学成分、力学性能和耐蚀性能。     

核电用钢的开发与展望

阐述了我国核电发展的现状及特点,重点介绍了鞍钢在核电用钢开发方面现有装备情况及取得的业绩,同时对我国钢铁企业未来核电用钢的研发方向进行了展望。     

清洁钢发展现状及今后进展

本文介绍了钢材的典型缺陷，服役条件对钢的夹杂物的要求和冶炼控制要点，以及近１０几年炉外精炼技术的进步所带来的钢的纯净度的变化和今后发展趋势。