CHENG Yongxing LI Genfu YU Shaoluo Shanghai University of Engineering Science
,
Shanghai
,
China WANG Huimin No.11 Institute of China State Shipbuilding Corp.
,
Shanghai
,
China Associate Professor
,
Dept.No.5
,
Shanghai University of Engineering Science
,
350 Xianxia Road
,
Shanghai
,
China
金属学报(英文版)
The Fe-Ni-Cr coating laver has been alloyed with 45 steel base metal by transverse.flow type CO_2 gas laser of maximum output 5kW.The characteristics of the melted zone and the es- sence of the“bright band”has been investigated using the electron microscopy.The results show that the“bright band”belongs to the melted zone and is a vertical section of the plane crystal,The width of the“bright band”equals the height of the plane crystal,which decreases with the increase of laser beam scanning rate and the decrease of laser power.This has been explained in terms of constitutional supercooling G/R.
关键词:
laser alloying
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null
,
null
GAO Hua XUE Lijue Shanghai University of Engineering Science
,
Shanghai
,
China Associate Professor
,
Dept.of Materials
,
Shanghai University of Engineering Science
,
350 Xianxia Road
,
Shanghai
,
China
金属学报(英文版)
Hydrogen induced cracking(HIC)of 0.3% C,1% Cr,1% Mn,1% Si high strength steel has been studied under simple mode Ⅰ,mode Ⅱ and(Ⅰ+Ⅱ)mixed mode loading conditions.Af- ter being hydrogen-charged in IN H_2SO_4 solution,the material behaved hydrogen embrittlement in all the cases studied.The threshold K_(ⅡH)/K_(ⅡX) of HIC under mode Ⅱ load- ing was 0.27,which was nearly the same as that K(ⅠH)/K_(ⅠX)=0.29 under mode Ⅰ loading. While the thresholds of-HIC under(Ⅰ+Ⅱ)mixed mode loading were 0.36,0.41 and 0.37 cor- responding to the K_Ⅱ/K_Ⅰ ratio of 0.27,0.4 and O.81.The results show that simple mode Ⅰ or mode Ⅱ loading is more susceptible to hydrogen embrittlement than(Ⅰ+Ⅱ)mixed mode. For explaining the experimental results,the effects of triaxial stress as well as plastic deformation ahead of crack tip has been discussed.
关键词:
(Ⅰ+Ⅱ)mixed mode
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null
朱静
,
李荣
,
张丽萍
金属学报
<正> 18Ni(350)马氏体时效钢是在18Ni(250)马氏体时效钢的基础上提高Co,Ti含量而形成的。对18Ni(250)钢的组织结构已经进行了较为系统的研究。提高Co,Ti含量使18Ni(350)钢时效后的强度明显高于18Ni(250)钢。关于18Ni(350)马氏体时效钢时效强化相的研究,已有很多报道,本文从时效结构的观察和分析入手,探讨18Ni(350)的强化机理并提出了合适的时效热处理制度。 试验用钢的化学成分(Wt-％)为:C0.007,Si0.005,Mn0.01,S0.005,P0.004,Co12.17,Ni17.99,Mo4.90,Ti1.31,A10.10,Fe余量。经双真空冶炼的钢锭,在
关键词:
M.L. Huang
,
H.X. Li
,
H. Ding
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Y.P.Ren
,
S.M. Hao
金属学报(英文版)
Alloys of Mg-Zn-La system in Mg rich corner at 350℃ have been prepared in this study. Scanning electron microscopy (SEM), electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA-EDS), and X-ray diffraction (XRD) have been used to identify the phase equilibrium and the composition of each phase in the alloys. As a result, the isothermal section of Mg-Zn-La system in Mg rich corner at 350℃ has been determined. The result shows that, in addition to some binary phases, there exists a linear ternary compound called T-phase in Mg-Zn-La system at 350℃, in which the La content is about 8 at. pct ±0.4at.pct and the Zn content is 8at. pct-48 at.pct. The T-phase has a C-centered orthorhombic crystal structure, and the lattice parameters are a=0.965-1.020 nm,b=1.121-1.142nm, c=0.950-0.977 nm.
关键词:
Mg-Zn-La system
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null
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null
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null
魏立群
,
陆济民
,
严家高
,
沈汉昌
上海金属
doi:10.3969/j.issn.1001-7208.2002.02.011
根据φ180/φ400×320及V100/V300×350四辊轧机的设备特点和产品情况,研究开发了能自动适应轧件宽度变化的变接触长度支承辊辊型曲线,以提高轧机的板型控制能力,使冷轧带钢的横向同板差下降约45%,轧制厚度精度提高40%,边裂现象明显减少,并有效防止支承辊辊面剥落,取得明显实效.
关键词:
冷带轧机
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支承辊
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变接触长度辊型
WAN Wen-juan
,
HAN Guang-wei
钢铁研究学报(英文版)
The microstructure of hot-rolled AEREX350 alloy under various heat treatments was investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is found that with increasing temperature, η phase precipitated firstly at grain boundaries in parallel at 800℃ and then began precipitating within grains at about 980℃. The η phase precipitating at grain boundaries played a role on preventing the migration of grain boundaries, and that precipitating within grains would develop as Widmanstätten structure with further increasing temperature. Both η phase dissolved at the temperature between 1085℃ and 1095℃, resulting in grain growth promptly due to release of pinning effect on grain boundaries. γ′ phase precipitated during the process of air cooling after hot-roll, and dissolved at temperature between 1010℃ and 1020℃.
关键词:
heat treatment;microstructure;precipitate;AEREX350
陈伟东
,
王建伟
,
王力军
,
卢世刚
,
陈松
稀有金属
doi:10.3969/j.issn.0258-7076.2008.01.013
通过恒温氧化实验研究了氢化锆在350～600℃纯氧中的氧化行为,分析了温度和时间对氧化层质量增重的影响规律,并借助Ⅺm,SEM等分析测试手段对氧化层的物相组成和截面形貌进行分析.结果表明,氢化锆的质量增重随着氧化温度的升高而增大,450℃以下,氧化反应速度很慢;500'～600℃温度范围内,氢化锆的质量增重与氧化时间的关系曲线符合抛物线规律.氧化层由内到外分为致密层和疏松层,氧化层主要由单斜相M-zeO2组成.
关键词:
氢化锆
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恒温氧化
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氧化层
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ZrO2
张朋
,
周立正
,
包建文
,
钟翔屿
,
刘刚
,
陈祥宝
复合材料学报
以苯乙炔苯酐(4-PEPA)为封端剂,异构联苯四甲酸二酐(α-BPDA)作为二酐单体,通过选择合适的二胺单体及优化配比,研制了耐温等级高于350℃,适用于RTM工艺的聚酰亚胺基体树脂HT-350RTM,选用U3160单向碳纤维织物作为增强体,采用RTM工艺制备了HT-350RTM树脂基复合材料层合板(U3160/HT-350RTM).结果表明:HT-350RTM树脂最低黏度可达390mPa·s,在280℃下保持黏度低于1Pa·s的时间大于2h,能够满足RTM工艺的要求.经过高温固化后,HT-350RTM树脂的玻璃化转变温度为392℃,热分解温度(分解5％)高达537℃.采用RTM工艺制备的U3160/HT-350RTM复合材料层合板孔隙率仅为0.34％,室温下具有良好的基本力学性能,315℃和350℃下的力学性能保持率均高于60％,能够满足350℃工况下的长期使用要求.
关键词:
RTM
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聚酰亚胺
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复合材料
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力学性能
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耐热性能
