检索结果-南通市图书馆

Theoretical calculation of the finishing rolling impact work in non-quenched and tempered Si-Mn steel

Science China(Technological Sciences) 2006年第2期49卷 137-146页

作者： LIU Zhilin1, LIN Cheng1 & WANG Ping2 1. Department of Materials and Chemical Engineering, Liaoning Institute of Technology, Jinzhou 121001, China 2. Mechanical Department, Armor technique Institute of PLA, Changchun 130117, China Department of Materials and Chemical Engineering Liaoning Institute of Technology Jinzhou China Mechanical Department Armor technique Institute of PLA Changchun China

Based on the hot-continuous rolling technology, the finishing rolling impact work α k of the non-quenched and tempered Si-Mn steel is theoretically calculated with the covalent electron number nA of the strongest bond in alloying phases, and the smallest interface electron density difference Δρ of alloying phase interface and the number of atom states σ which keep the interface electron density continuous. Calculations show that the solution strengthening, the precipitation strengthening, and the interface strengthening will result in the decrease of the finishing rolling impact work α k, and the effects of the number of atom states σ which keep the interface electron density continuous on the finishing rolling impact work α k are different. Taking the impact work and the number of atom states σ 0 keeping the electron density continuous of the phase interface α-Fe/α-Fe-C between α-Fe and α-Fe-C as reference values, the impact work of the interface will increase when σ of some interface is larger than σ 0; otherwise, the impact will decrease. Therefore, the finishing rolling impact work α k can be calculated with the impact value of the refined α-Fe matrix and the influence amounts caused by the solution strengthening, the precipitation strengthening, the interface strengthening, and the number of atom states σ which keep the interface electron density continuous. The calculated results agree well with the measured ones. In this paper, the effect of S on the impact work is also discussed.

关键词： electron structure parameters, non-quenched and tempered steel, impact work and calculation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical calculation of the impact work in the alloying non-quenched and tempered steel

引用

Science China(Technological Sciences) 2006年第3期49卷 257-273页

作者： LIU Zhilin1, LIN Cheng1 & GUO Yanchang2 1. Department of Materials and Chemical Engineering, Liaoning Institute of Technology, Jinzhou 121001, China 2. The Technical Center of Benxi Iron and Steel Group Corporation, Benxi 117000, China Department of Materials and Chemical Engineering Liaoning Institute of Technology Jinzhou China The Technical Center of Benxi Iron and Steel Group Corporation Benxi China

Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr, Ni, Mo, W, Cu, V, Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases, the smallest electron density difference ?ρ of phase interfaces, and the number of atom states σ (σ′) which keep the interface electron density continuous. The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms. The solution strengthening, interface strengthening, precipita- tion strengthening of pearlite, and dispersion strengthening will result in the decrease of the finishing rolling impact work; the refinement strengthening, the precipitation strength- ening of V, Nb and Ti in α-Fe-C-V(Nb, Ti), and the residual austenite containing Ni on the boundary of α-Fe-C-Ni will increase the impact work; and the increments or decrements can be calculated with nA, ?ρ, σ (σ′) and weights of alloying elements. The calculation formulas of the finishing rolling impact work in this paper are intergraded with the sug- gested ones of the finishing rolling tensile strength, yield strength, and elongation of the non-quenched and tempered steel. The calculated results agree well with the measured ones.

关键词： alloying non-quenched and tempered steel, electron structure, impact work, calculation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Riesz basis, Paley-Wiener class and tempered splines

引用

Science China Mathematics 2000年第10期43卷 1075-1082页

作者：房艮孙龙晶凡 Department of Mathematics Beijing Normal University Beijing 100875 China

The Marcinkiewicz-Zygmund inequality and the Bernstein inequality are established on ?2m (T, ?) ∩ L2 (?) which is the space of polynomial splines with irregularly distributed nodesT = {t j } j ∈?, where {t j }j∈? is a real sequence such that {e it ξ} j }j ∈? constitutes a Riesz basis for L2([ ?π,π]). From these results, the asymptotic relation is proved, where B π,2 denotes the set of all functions from L2( R) which can be continued to entire functions of exponential type ? ?, i.e. the classical Paley-Wiener class.

关键词： Riesz basis entire functions tempered splines asymptotic relation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of cooling rate on microstructure and mechanical properties of CB2 tempered martensitic steel

引用

China Foundry 2020年第2期17卷 158-166页

作者： Yu-lin Ma Yue Liu Li-ping Zhang Xu Jiang Chun-ming Liu School of Materials Science and Engineering Northeastern UniversityShenyang 110189China The Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110189China

The cooling rate of casting has a significant effect on microstructure and mechanical properties of *** 9Cr-1.5Mo-1Co cast steel,referred to as CB2,is one of the most promising alloys for various cast components to be used under ultrasupercritical *** this study,HRTEM,SEM,and XRD methods were used for qualitative and quantitative analyses of contents,phases,and sizes of the inclusions and precipitates,as well as microstructure observation of the tempered martensitic steel at different cooling *** tensile tests were conducted to characterize the material mechanical *** show that the size of the boron nitride and precipitate,the width of the martensite lath and the content of theδ-ferrite are reduced as the cooling rate increases from 5-8℃·min^-1(CB2-S steel)to 50-60℃·min^-1(CB2-F steel).The precipitates are mainly composed of M23C6 and a small amount of *** average diameters of the M23C6 precipitates in CB2-F and CB2-S are 202 nm and 209 nm,*** inclusions are mainly composed of BN,Al2O3 and MnO2,and the inclusion ratios are 0.1969%for the CB2-F and 0.06556%for CB2-S *** average martensite lath widths of CB2-F and CB2-S steels are 289 nm and 301 nm,***,the M3C having a diameter of about 150 nm and a thickness of 20 nm is observed in theδ-ferrite of the tempered CB2-S *** presence of theδ-ferrite reduces the precipitation strengthening and dislocation density in CB2-S *** addition,the lower cooling rate stabilizes theδ-ferrite structure at room temperature.

关键词： tempered martensitic steel casting microstructure M23C6 mechanical properties inclusions δ-ferrite

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hybrid Laser-GMAW Welding of High Strength Quenched-tempered Steels

引用

稀有金属材料与工程 2011年第S4期40卷 102-105页

作者： Radovan Kovacevic Research Center for Advanced Manufacturing Southern Methodist UniversityTexas 75205United States

High-strength quenched and tempered (HSQT) steels have been widely used in structural applications where light weight is of primary design *** metal arc welding is a common way to join QT *** GMAW is used to join the HSQT steel,multi-pass is usually required to achieve full *** addition,weld crack is often observed because of HSQT steel's high susceptibility to hydrogen *** addition,due to the large amount of heat input from the arc,the heat affected zone is often *** reduces the ductility and strength of welds and makes the weld weaker than the base *** this study,a hybrid laser/GMAW process is proposed to produce butt joint for 6.5mm thick HSQT A514 steel *** diffusion mechanism is first discusses for GMAW and hybrid laser-GMAW welding *** transfer mode during the hybrid laser/GMAW welding process is also analyzed.A high speed CCD camera with 4000 frame/second is used to monitor the welding process in real *** obtained by GMAW and hybrid laser/GMAW techniques are compared and tested by static lap shear and dynamic *** of gap between two metal plates and laser beam/GMAW torch spacing on weld property are *** appropriately choosing these two parameters,crack-free butt joints with full penetration can be successfully obtained by the hybrid laser/GMAW welding process for HSQT A514 steel plate.

关键词： hybrid laser-GMAW welding high strength quenched and tempered steels hydrogen induced cracking

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Levy tempered Stable金融资产收益分布及其CF-CGMM估计方法研究

引用

中国管理科学 2009年第3期17卷 18-26页

作者：刘志东陈晓静中央财经大学北京100081 联想集团北京100085

本文在对经典的和修正的Levy tempered stable分布进行研究的基础上,结合现实中金融资产收益分布的实际特征,分析Levy tempered stable分布在构建模拟金融资产价格过程的Levy Jump模型的优势。由于这类分布的概率密度函数不存在解析式,... 详细信息

本文在对经典的和修正的Levy tempered stable分布进行研究的基础上,结合现实中金融资产收益分布的实际特征,分析Levy tempered stable分布在构建模拟金融资产价格过程的Levy Jump模型的优势。由于这类分布的概率密度函数不存在解析式,直接应用传统MLE方法进行参数估计存在困难。为此,根据特征函数与概率密度函数的等价关系,本文建立基于特征函数(CF)具有连续矩条件的GMM(简称CF-CGMM)的Levy tempered Stable分布参数估计方法。同时,利用恒生指数、上证指数、标准普尔500指数数据对以上分布和参数估计方法进行实证研究,并根据参数计算结果和统计假设检验,对不同Levy tempered Stable分布的拟和优度进行检验和比较。本文也在参数估计和统计检验工作的基础上,根据Levy tempered Stable分布模型中不同参数的含义,结合实证计算的结果,对恒生指数、上证指数、标准普尔500指数价格运动特征给出符合现实的解释。

关键词： Levy tempered stable分布特征函数跳跃连续矩条件 GMM 估计

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Correlation between microstructure and impact toughness of weld heat-affected zone in 5 wt.% manganese steels

引用

Journal of Iron and Steel Research International 2019年第7期26卷 761-770页

作者： Jun-hui Li Hong-hong Wang Qiang Luo Li Li Chao Sun R.D.K. Misra The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Wuhan 430081 Hubei China Research Institute of Nanjing Iron and Steel Co. Ltd. Nanjing 210035 Jiangsu China Laboratory for Excellence in Advanced Steel Research Department of Metallurgical Materials and Biomedical Engineering University of Texas at El Paso El Paso TX 7996& USA

The microstructure in welding heat-affected zones of 5 wt.% manganese steels was studied, and its effect on impact toughness was analyzed. The simulated coarse-grained heat-affected zone (CGHAZ) had the lowest impact toughness of ~39 J at — 40℃ because of coarse-grained structure and least volume fraction of retained austenite (RA) of 1.2 vol.%. The impact toughness of simulated intercritical heat-affected zone (ICHAZ) and fine-grained heat-affected zone (FGHAZ) were ~165 and ~45 J, respectively, at — 40℃. The effective grain size of simulated FGHAZ was smaller than that of the simulated ICHAZ. Furthermore, microstructural investigation revealed that the simulated FGHAZ and ICHAZ had similarity in volume fraction and stability of RA. However, tempered martensite was present in ICHAZ and absent in FGHAZ. It is proposed that the presence of tempered martensite contributed to good impact toughness in simulated ICHAZ.

关键词： 5 wt.% manganese steel Welding heat-affected zone Retained austenite tempered martensite Impact toughness

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

OPTIMIZATION OF MATERIAL PROPERTIES THROUGH THE LINKAGE OF SIMULATION CALCULATIONS WITH THE REAL ROLLING PROCESS OF DIFFERENT STEEL GRADES FOR BABS AND WIRE ROD

引用

Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 281-290页

作者： R. Kohlmann M. Kruse M. Meyer and U. Plociennik( 1) Betriebsleiter Qualitatsstelle, Krupp Edelstahl Profile, Siegen 2)Research and Development, SMS Schloemann Siemap AG, Dusseldorf/Germany)

Material properties were optimized through the linkage of numericalsimulation with the real rolling pro- cess. A few different steel grades for bars and wire rode were taken as the *** *** commerical FEM code MARC/MENTAT was used for the numerical simulation of the three - dimensional elas- toplastic rolling process coupled with *** simulation calculation for temperation for temperature control in- side the rolling mill was carried out by use of the SMS - developed CCT system (controlled coling technolgy). New rolling - technological precess was developed for bars and wire rods based on the numerical *** 38MnSiVS5 and steel 41Cr4 were taken as the examples. Keywrods: rolling,numerical simulation, material property optimigation

关键词： REAL tempered hardening drawing Controlled heading

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Existence of Random Attractor Family for a Class of Nonlinear Higher-Order Kirchhoff Equations

引用

International Journal of Modern Nonlinear Theory and Application 2019年第2期8卷 41-52页

作者： Guoguang Lin Changqing Zhu School of Mathematics and Statistics Yunnan University Kunming China

The existence of random attractor family for a class of nonlinear nonlocal higher-order Kirchhoff partial differential equations with additive white noise is studied. The weak solution of the equation is established by the Ornstein-Uhlenbeck process to deal with the random term, and a bounded random absorption set is obtained. And then, the existence of the random attractor family is proved by the isomorphism mapping method.

关键词： Stochastic Dynamical Systems Random Attractor Family White Noise Ornstein-Uhlenbeck Process tempered Sets

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Glass Thickness and Fragmentation Behavior in Stressed Glasses

引用

New Journal of Glass and Ceramics 2012年第4期2卷 116-121页

作者： Hoikwan Lee Seoyeong Cho Kyungmin Yoon Jaeho Lee Glass Tech Research Center Samsung Corning Precision Materials Asan Korea

Breakage patterns, residual stress, and fractured surfaces on tempered glasses are investigated to find the correlation among glass thickness, tempered level, and the number of fragments, particularly when the glass thickness is less than 4 mm. Relatively thin glasses require high compressive stress for producing fragments, and the required compressive stress is increased with decreasing glass thickness (3.2 to 2.1 mm). By analyzing the residual stress of glasses before and after the fragmentation test, we observe that a relatively thin glass spends more stored energy to generate a new fracture surface and stores less energy for the second cracking as compared to thick glasses. Fractography shows that all glasses have a similar characterization on the fractured surface irrespective of glass thickness. However, the only dif- ference is the depth of the compressive layer. By reducing the depth of the compressive layer to less than approx. 20% of the glass thickness, it is observed that the possibility of producing small fragments is dramatically decreased. There- fore, this study confirms that the compressive stress and its depth are essential as key factors contributing to the achievement of a relatively high fragmentation using a thin glass.

关键词： Fragmentation Breakage Pattern Residual Stress Thin tempered Glass Fractured Surface

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：