60CrMnMo锻造轧辊脱肩原因分析

通过对60CrMnMo锻造轧辊脱肩样品的一系列分析,明确了其开裂原因。轧辊在生产过程中吊空冷时间长、晶界析出脆性碳化物、冷却速度快、体积变化大、淬火应力大,形成淬火裂纹并造成锻件开裂。     

铸铁缸套等离子淬火网纹状轨迹交叉点的分析

本文通过显微组织观察和显微硬度检测，对气缸套网纹状硬化轨迹交叉点处的组织与硬度作了深入的研究分析。结果表明：交叉点处的组织为二次加热淬火得到的隐针马氏体，其硬度高于其它硬化区。     

飞机航炮滑板制造工艺研究探讨

某型飞机航炮射击500发后,滑板与杠杆产生疲劳裂纹。通过对滑板工作原理和制造工艺的研究,运用数控铣技术,设计出一套新的滑板制造工艺。对由该工艺生产的产品进行试验,验证了新工艺的有效性,较好地解决了疲劳裂纹问题,对延长飞机航炮滑板使用寿命具有重要意义,获得了一种航空维修零备件制造中运用新工艺、新技术、新设备代替以往仿形铣加工的方法,为附件修理、制造提供了一种可行的方法。     

油井钻具用SAE4137M钢生产实践

介绍了油井钻具用SAE4137M钢冶炼及加工研制生产工艺,分析了生产过程各工艺控制要点,并对生产及用户使用中容易产生的非金属夹杂物及残余元素含量超标、淬火处理开裂、调质性能不合格等质量问题进行了逐项分析,提出了针对质量问题的控制措施。     

控制薄壁细长径零件淬火变形的工艺措施

从某产品零件淬火变形原因分析出发,较详细地讨论了此类产品淬火变形机理和控制变形的具体方法,取得了理想的效果。     

Detection of wood cell wall porosity using small carbohydrate molecules and confocal fluorescence microscopy

A novel approach to nanoscale detection of cell wall porosity using confocal fluorescence microscopy is described. Infiltration of cell walls with a range of nitrophenyl‐substituted carbohydrates of different molecular weights was assessed by measuring changes in the intensity of lignin fluorescence, in response to the quenching effect of the 4‐nitrophenyl group. The following carbohydrates were used in order of increasing molecular weight; 4‐nitrophenyl β‐D‐glucopyrano‐side (monosaccharide), 4‐nitrophenyl β‐D‐lactopyranoside (disaccharide), 2‐chloro‐4‐nitrophenyl β‐D‐maltotrioside (trisaccharide), and 4‐nitrophenyl α‐D‐maltopentaoside (pentasaccharide). This technique was used to compare cell wall porosity in wood which had been dewatered to 40% moisture content using supercritical CO_2, where cell walls remain fully hydrated, with kiln dried wood equilibrated to 12% moisture content. Infiltration of cell walls as measured by fluorescence quenching, was found to decrease with increasing molecular weight, with the pentasaccharide being significantly excluded compared to the monosaccharide. Porosity experiments were performed on blocks and sections to assess differences in cell wall accessibility. Dewatered and kiln dried wood infiltrated as blocks showed similar results, but greater infiltration was achieved by using sections, indicating that not all pores were easily accessible by infiltration from the lumen surface. In wood blocks infiltrated with 4‐nitrophenyl α‐D‐maltopentaoside, quenching of the secondary wall was quite variable, especially in kiln dried wood, indicating limited connectivity of pores accessible from the lumen surface.     

Design of the multi-stage quenching process for 7050 aluminum alloy

In order to attain good hardenability in the single-stage quenching process of Al–Zn–Mg–Cu alloys, rapid cooling rate is often desirable. But this would inevitably increase the residual stress. Therefore, the aim of this study is to achieve coupling control of the cooling rate and the residual stress by using the multi-stage quenching process. First, a series of single-stage quenching tests were conducted based on the end quenching equipment. Then in the double-stage quenching tests, a higher cooling rate was obtained comparing to the single-stage quenching. Based on this discovery, three kinds of multi-stage quenching processes were designed based on the experimental results of the single-stage quenching tests. The mechanism of the multi-stage quenching has been analyzed by comparing the cooling curves, the microstructure, the hardening depth, and the maximum residual stress. Furthermore the optimal multi-stage quenching process for 7050 aluminum alloy plate was obtained.     

热处理模拟软件Thermal Prophet的开发与应用

Thermal Prophet是最近开发的一款具有自主知识产权的热处理数值模拟软件。本文介绍了其基本架构、技术特点和基本功能。以热作模具钢模块淬火为例应用本软件进行了模拟,得到的畸变趋势与实际测量结果一致。通过考虑和忽略相变塑性两种模拟结果的对比,分析了相变塑性对淬火畸变所起的作用,指出了相变塑性是模拟淬火过程不可忽略的重要因素。     

Extended solubility in non-equilibrium Pb/Fe system

Nanostructured Pb/Fe alloys have been produced by means of mechanosynthesis and co-deposition methods in powder and film forms, respectively, in both sides of the composition range. Low temperature Mössbauer results obtained from the films have indicated the presence of interstitial Fe in fcc-Pb lattice, with maximum Fe solubility of 3 at.%. This Fe configuration has an atomic diffusion effect with increasing temperature, resulting in formation of small Fe clusters. On the other hand, milling Fe and Pb powders mixture up to 700 h only produced iron-rich Pb/Fe phases with high degree of chemical disorder established due to different atomic radii of Pb and Fe, as shown by a broad Mössbauer subspectra. The milling procedure extended the Pb solubility limit in Fe matrix to 6 at.%. Therefore, our results of films and milled powders indicated that one has extended the known solubility limit for this system.     

Reproducible on-off switching of the light emission from the electroluminescent device containing a spin crossover complex

To examine the mechanism of a reproducible on-off switching of light emission from a novel organic electroluminescent (EL) device consisting of a spin crossover complex of [Fe(dpp)₂](BF₄)₂ (dpp = 2,6-di(pyrazol-1-yl)pyridine) and chlorophyll a, we have investigated the EL properties of an ITO/chlorophyll a:[Fe(dpp)₂](BF₄)₂/Al device. The comparison with a reference device not containing [Fe(dpp)₂](BF₄)₂ revealed that the introduction of [Fe(dpp)₂](BF₄)₂ results in small threshold voltage and large external quantum efficiency. Moreover, the EL spectra in the low-temperature region, where [Fe(dpp)₂](BF₄)₂ is in the low-spin state, showed the emission from the ITO electrode, suggesting that injected electrons pass through the active layer via [Fe(dpp)₂](BF₄)₂.