S.B. Zhang and H. Nejishi (Department of Mechanical Engineering and Intelligent Systems
,
University of E feetro- Communications
,
Chofugaoka 1-5-1
,
Chofu-shi
,
Tokyo 182-8585
,
Japan)
金属学报(英文版)
In this paper local compressive deforming of a hexagonal tube of aluminum (JISA1050) is investigated by an electromagnetic forming. The hexagonal tubes are annealed for 1h. at 400℃, which have 55mm width with 1mm thickness, and 10mm corner edius. The deformed ation of the hexagonal tube, i.e., bead width, is 10, 15, 20mm, respectively. The magnetic flux density in the gap between the field shaper and the external surface of hexagonal tube is measured, and the result is that the magnetic flux density for a given voltage is almost identical along the gap) and decreases with increasing the gap. The profiles and the strain distribution of the hexagonal tube de- formed are affected by the change Of the charging voltage and the dimensions of a bead width. The greater compressive strum in the cireuwtrential direction is develOPed on plane part near corner,while tensile strain on the corner occurs. A metallic block is inserted inside the hexagonal tube so that uniform profile can be obtained. The simulation of the forming is performed by a finite-element method and compared with the experimental results.
关键词:
electromagnetic forming
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null
,
null
,
null
,
null
Journal of Materials Science
Characterizations of the microstructure and mechanical property of the fusion boundary region of an Alloy 182-A533B low alloy steel (LAS) dissimilar weld joint were conducted. The existence of type-II boundary that parallels to the fusion boundary in the dilution zone (DZ) of Alloy 182 within a distance of about 50 mu m was observed. The chemical composition transition was found in the narrow zone between the type-II and the fusion boundaries. Highest hardness was also found in this narrow zone in the fusion boundary region, implying a high residual strain level in the narrow zone. Lath martensite was observed in both sides of the type-II boundary in DZ, suggesting the localized enrichment of Fe and C adjacent to the type-II boundary due to the diffusion from LAS to DZ. Massive precipitations of carbides were observed on the type-II boundary but not on the fusion boundary. In addition, the orientation relationship at the fusion boundary between the lath martensite in the heat-affected zone in LAS and the austenite in the DZ was found to be Bain, K-S and N-W relationships.
关键词:
low-carbon steels;lath martensite;metal welds;morphology;crystallography;evolution
王驰
,
冉广
,
雷鹏辉
,
陈芙梁
材料热处理学报
在20 ～600℃范围内对国产SA-182F304钢进行了温度效应下的拉伸行为研究.采用光学显微镜、透射电镜、扫描电子显微镜、XRD以及显微硬度仪对原始态和拉伸断裂试样进行了微观组织与微观化学分析与表征.试验结果表明,在晶粒度为5.5级的钢基体中分布着粗系、moy级别为1.5级的B类和细系、moy级别为1.0级的D类宏观夹杂物,分别占0.0317％和0.0158％,这些夹杂物容易出现在拉伸断口的韧窝处.钢基体中分布着大量平行与缠结的位错,析出相主要为FCC结构的Ti(Cr,Fe,Mn)2.屈服强度、拉伸强度和伸长率随着温度的升高而降低,而断面收缩率却保持在80％左右,表现出良好的塑性,断口以韧窝为主.拉伸导致了钢基体的显微硬度显著提高,比原始态钢的相应值提高了约一倍.显微硬度的增加来源于钢基体中的位错增殖,而非相变的结果,拉伸并没有导致奥氏体向马氏体发生明显转变.随着拉伸温度升高,奥氏体晶粒的回复加剧,位错密度逐渐降低,纤维状的组织明显降低.
关键词:
SA-182 F304钢
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拉伸性能
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微观组织
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核反应堆
伊雄海
,
时逸吟
,
赵善贞
,
孟令华
,
潘孝博
,
盛永刚
,
韩丽
,
朱坚
,
邓晓军
色谱
doi:10.3724/SP.J.1123.2016.06056
建立了气相色谱-四极杆-飞行时间质谱同时筛查食品中182种香港《食物内残余除害剂规例》农药残留的分析方法.样品经含0.1％ (v/v)甲酸的乙腈溶液提取,改进的QuEChERS方法净化,采用Agilent HP-5MS色谱柱(30 m×0.25 mm×0.25 μm)进行分离.样品经电子轰击源电离,一级质谱采用全扫描模式完成化合物的定性和定量检测,对疑似物质进行二级谱库检索确证.考察了10种典型食品基质(大米、香菇、黄豆、菠菜、西红柿、西兰花、柚子、胡萝卜、生菜、黄瓜)的基质效应.在10～ 500 μg/kg范围内,182种目标化合物的线性关系良好(r＞0.99),方法的定量限(S/N≥10)为10～ 100 μg/kg,在3个添加水平下的平均加标回收率分别为66.1％～ 121.5％、75.4％～125,8％、77.2％ ～ 128.9％,相对标准偏差(RSD)为0.8％～ 17.6％(n=6).该方法操作简单、耗时短、灵敏度高、稳定性好,可显著降低日常筛查检测的成本,具有实际应用价值.
关键词:
气相色谱-四极杆-飞行时间质谱
,
筛查
,
农药残留
,
食品
Corrosion Science
Stress corrosion cracking (SCC) in the fusion boundary (FB) region of an Alloy 182-low alloy steel (LAS) dissimilar weld joint in 288 C water was investigated by experiments and finite element simulation. Creviced bent beam and crack growth rate (CGR) experiments showed that, while the FB was a barrier to SCC growth, further crack growth into LAS was activated by a combined effect of sulfate and dissolved oxygen in water. Finite element simulation suggested that a positive gradient of hardness as the crack approached to the FB in dilution zone caused decreased CGR. Role of microstructure and water chemistry in SCC was discussed. (C) 2011 Elsevier Ltd. All rights reserved.
关键词:
Low alloy steel;Alloy;SEM;TEM;Stress corrosion;Welding;environmentally-assisted cracking;nickel-base alloys;stainless-steels;susceptibility;property
J.M.Gong
金属学报(英文版)
In this paper, the effect of carbon migration on creep properties of Cr5Mo dissimilar welded joints with Ni-based (Inconel 182) and Cr23Ni13 (A302) austenitic weld metal was investigated. Carbon migration near the weld metal/ferritic steel interface of Cr5Mo dissimilar welded joints was analyzed by aging method. Local creep deformations of the dissimilar welded joints were measured by a long-term local creep deformation measuring technique. The creep rupture testing was performed for Cr5Mo dissimilar welded joints with Inconel 182 and A302 weld metal. The research results show that the maximum creep strain rate occurs in the decarburized zone located on heat affect zone (HAZ) of Cr5Mo ferritic steel. The creep rupture life of Cr5Mo dissimilar welded joints with A302 weld metal decreases due to carbon migration and is about 50％ of that welded with Inconel 182 weld metal.
关键词:
dissimilar welded joint
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null
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null
沈秋婉
,
郑瑛
,
马飞艳
,
丁宁
,
郑楚光
工程热物理学报
钙钛矿型金属氧化物是优良的制备供富氧燃烧所需的02/C02的氧载体,本文采用柠檬酸法制备系列SrCo1-xFex03-δ (x=0.2,0.4,0.6,0.8)钙钛矿型氧化物,并采用X射线衍射分析来表征SrCo0.8Fe0.2O8-δ (SCF182)反应前后的物相变化和晶体结构.同时在固定床上选择不同的运行条件对SCF182的释氧性能进行研究,包括吸附温度、吸附时间、脱附温度和循环特性.结果表明,SCF182的最佳吸附温度和脱附温度均为850℃C,最佳吸附时间为1h,循环性能良好,是可以为富氧燃烧提供稳定的O2/C02循环气体的良好材料.
关键词:
富氧燃烧
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钙钛矿
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固定床
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制氧
周俊虹
,
袁双龙
,
黄飞鸿
,
周永涛
,
杨云霞
,
陈国荣
稀有金属材料与工程
为提高银粉在有机相中的润湿性,根据Washburn方程,采用透过高度法测定二丙二醇丙醚、丁基卡必醇醋酸酯和松油醇3种溶剂对银粉的润湿角,并在3种溶剂中分别加入辛酸、三乙醇胺、失水山梨醇三油酸酯和BYK182 4种分散剂观察润湿角的变化.结果表明:松油醇对银粉的浸润性最好,将非离子型高分子表面活性剂BYK182加入二丙二醇丙醚和丁基卡必醇醋酸酯2种溶剂中可以改善对银粉的润湿性.
关键词:
银粉
,
Washburn方程
,
分散性
,
润湿
