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Dynamic and Static Recrystallization Behavior of Low Carbon High Niobium Microalloyed Steel

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Journal of Iron and Steel Research International 2011年第1期18卷 55-60页

作者： LAN Liang yun QIU Chun lin ZHAO De-wen gao xiu hua DU Lin-xiu State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The recrystallization behavior of a low carbon high niobium microalloyed steel was investigated using continuous and interrupted hot compression tests. The results showed that the initiation of dynamic recrystallization （DRX） could be detected from inflection in the plot of the strain hardening rate against stress regardless of the stress peak appearance. According to the Zener-Hollomon parameter equation, the activity energy of DRX （Qad） was ob tained and a new modified expression calculating Qdef was proposed in consideration of the chemical composition of experimental steel. Applying the 2% offset method, the static softening fraction was determined. The graphic representation of the softening fraction vs interruption time gave the information about the non-static reerystallization temperature （about 1 000℃ ） and the relationship of precipitation time temperature. Static recrystallization kinetics followed the Avrami＇s law at high deformation temperature, and different values of the exponent m were given to illustrate the effect of niobium element on static recrystallization at different deformation temperatures.

关键词： dynamic recrystallization static recrystallization high niobium microalloyed steel activity energy

Microstructural Evolution and Mechanical Properties of Nb-Ti Microalloyed Pipeline Steel

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Journal of Iron and Steel Research International 2011年第2期18卷 57-63页

作者： LAN Liang-yun QIU Chun-lin ZHAO De-wen gao xiu-hua State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

The correlation between microstructures and mechanical properties of a Nb-Ti microalloyed pipeline steel was investigated. The results revealed that with decreasing the finish rolling temperature and the cooling stop tern perature, the matrix microstructure was changed from quasi-polygonal ferrite to acicular ferrite, as a result of improvement of both strength and low temperature toughness. By means of electron backscattered diffraction observation, an effective acicular ferrite packet contained several low angle boundaries or subboundaries plates which made important contributions to improvement of strength. It was found that many fine quasi-polygonal ferrite grains with high angle boundaries as the toughening structure were introduced into the acicular ferrite matrix to refine effective grain size and improve the toughness.

关键词： pipeline steel acicular ferrite mechanical property electron backscattered diffraction

Non-Oriented Fe-Si Thin Strip Produced from Grain Oriented Fe-Si Strip by CSR

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Journal of Iron and Steel Research International 2004年第4期11卷 34-37页

作者： YE He-zhou QI Ke-min gao xiu-hua QIU Chun-lin LIU En Northeastern University

The grain oriented silicon strip was rolled by cross shear rolling(CSR)and then annealed to manufacture non-oriented thin silicon strip of high *** recrystallization of rolled grain-oriented silicon steel into non-oriented silicon steel was *** this purpose,CSR is better than conventional rolling,and the higher the mismatched speed rate is,the better the properties of the non-oriented thin silicon strip *** optimum annealing schedule is heating at 1 000 ℃for 1hin pure hydrogen atmosphere added with H2 S of 0.001 0 %.

关键词： grain oriented silicon strip non-oriented silicon strip cross shear rolling recrystallization texture

Application of Artificial Neural Network to Predicting Hardenability of Gear Steel

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Journal of Iron and Steel Research International 2006年第6期13卷 71-73页

作者： gao xiu-hua QI Ke-min DENG Tian-yong QIU Chun-lin ZHOU Ping DU Xian-bin State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Technical Center Laiwu Iron and Steel Co Ltd Laiwu 271104 Shandong China

The prediction of the hardenability and chemical composition of gear steel was studied using artificial neural networks. A software was used to quantitatively forecast the hardenability by its chemical composition or the chemical composition by its hardenability. The prediction result is more precise than that obtained from the traditional method based on the simple mathematical regression model.

关键词： artificial neural network (ANN) gear steel hardenability 20CrMnTiH

半化学法制备PMW-PNN-PT粉体的反应机理研究

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无机化学学报 2005年第6期21卷 900-904,F010页

作者：崔斌高秀华高武史启祯西北大学化学系/陕西省物理无机化学重点实验室西安710069

The mechanism of perovskite 0.1Pb(Mg1/2W1/2)O3-0.6Pb(Ni1/3Nb2/3)O3-0.3PbTiO3 (abbreviated PMW-PNN-PT) phase formation by Semichemical Method has been studied. The precursors were prepared by adding aqueous solution of Mg(Ac)2 and Ni(AC)2 rather than solid MgO and NiO to the alcoholic slurry of PbO, WO3, Nb2O5 and TiO2. The TG-DTG and DSC of the precursors and XRD analysis of the powders at various calcination temperature showed that the mechanism of this method was different from that of the conventional mixed oxide method. The aqueous Mg(Ac)2 and Ni(Ac)2 reacted with PbO to form basic lead acetate, basic magnesium acetate and basic nickel acetate and so on. With the increase of calcination temperature these basic salt decomposed to form nascent PbO, MgO and NiO, which improved the reactivity and distribution of PbO, MgO and NiO. In addition, the formation of PbWO4 and pyrochlore phase Pb3Nb2O8 in the process was in favor of the pervoskite PMW-PNN-PT phase formation. At the calcining temperature of 850 ℃, the perovskite phase reached 98%.

关键词：半化学法反应机理焦绿石相钙钛矿相铅系弛豫铁电陶瓷相组成

Local magnetic moment oscillation around an Anderson impurity on graphene

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 192-201页

作者： Shuai Li Zhen Ma Jin-hua gao School of Science Hebei University of Science and Technology School of Electronics and Information Zhengzhou University of Light Industry School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology

We theoretically investigate the spin resolved Friedel oscillation （FO） and quasiparticle interference （QPI） in graphene induced by an Anderson *** the impurity becomes magnetic,the resulted FO becomes spin dependent,which gives rise to a local magnetic moment oscillation with an envelop decaying as r-2in real space in the doping ***,at half filling,the electron density and local magnetic moment will not oscillate but decay as *** spin resolved FO has both sublattice and spin ***,the local magnetic moment decay at half filling only occurs at one sublattice of graphene,which is quite like the phenomenon observed in the STM experiment (***ález-Herrero et al.,Science 352,437 （2016）).We further give an analytic formula about such spin dependent FO based on the stationary phase ***,we study the interference of quasiparticles around the magnetic impurity by calculating the spin dependent Fourier-transformed local density of states （FT-LDOS）.Our work gives a comprehensive understanding about the local magnetic moment oscillation around an Anderson impurity on graphene.

关键词： Friedel oscillation local magnetic moment graphene Anderson impurity

PMW-PNN-PT陶瓷的制备及介电性能研究

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无机化学学报 2006年第9期22卷 1685-1689页

作者：高秀华崔斌史启祯西北大学化学系/陕西省物理无机化学重点实验室西安710069

0.29Pb(Mg1/2W1/2)O3-0.41Pb(Ni1/3Nb2/3)O3-0.30PbTiO3 + 0.002 5MnO2 + xWO3(PMW-PNN-PT) ceramics were prepared by Semichemical Method. The Mg(Ac)2, Ni(Ac)2, and Mn(NO)3 solution rather than MgO, NiO and MnO2 were added to the slurry of PbO, WO3, Nb2O5 and TiO2 and then calcined at 850 °C for 2 h. Then the sample was sintered at 1 100～1 200 °C for 2 h. The effect of sintering temperature and WO3-excess amounts on the phase constitute, microstructure and the dielectric characteristics was investigated. The result showed that the PMW-PNN-PT powders with pure pervoskite phase were prepared by single-step calcination. The development of sintered temperature contributes to the increase of dielectric constant and the flatness of dielectric temperature dependence. But the dielectric properties will be worse if the sintered temperature is too high. The increase of WO3-excess level lead to an increase of Pb2WO5 phase and the flatness of dielectric curves, but the dielectric constant will be decreased. The proper WO3-excess amount of X7R type PMW-PNN-PT ceramics is 5mol% and the proper sintering condition is 1 150 °C for 2 h, the maximum dielectric constant is 5 395.

关键词：半化学法 X7R型介电常数 “壳-芯”结构

微合金元素Nb对B5钢力学性能和微观组织的影响

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材料热处理学报 2021年第4期42卷 102-108页

作者：吉光高秀华龙金花东北大学轧制技术及自动化国家重点实验室辽宁沈阳110819 江苏沙钢集团淮钢特钢股份有限公司江苏淮安223002 江苏天淮钢管有限公司江苏淮安223001

利用扫描电镜(SEM)、光学显微镜(OM)和电子万能试验机等研究了微合金元素Nb对高碳耐磨钢球用B5钢微观组织和力学性能的影响。结果表明:添加质量分数为0.040%的铌元素后,高碳耐磨钢球用B5钢的晶粒尺寸从27.60μm降低到21.25μm,珠光体团... 详细信息

利用扫描电镜(SEM)、光学显微镜(OM)和电子万能试验机等研究了微合金元素Nb对高碳耐磨钢球用B5钢微观组织和力学性能的影响。结果表明:添加质量分数为0.040%的铌元素后,高碳耐磨钢球用B5钢的晶粒尺寸从27.60μm降低到21.25μm,珠光体团尺寸从12.1μm减小至7.7μm,珠光体片层间距降低了约15%,渗碳体片展弦比减小;第二相粒子(Nb, Ti)C的析出起到沉淀强化的同时,也促使渗碳体片层出现碎化、断开现象。添加质量分数为0.040%的铌元素后,提高了高碳耐磨钢球用B5钢的强度和塑性,其抗拉强度为1026 MPa;断后伸长率为11.8%。

关键词：铌微合金化高碳耐磨钢球用钢抗拉强度珠光体片层第二相粒子

高韧性420MPa级桥梁钢开发及强化机制分析

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东北大学学报（自然科学版） 2018年第8期39卷 1123-1126页

作者：高彩茹刘宝喜潘欢高秀华东北大学轧制技术及连轧自动化国家重点实验室辽宁沈阳110819 唐山钢铁集团有限责任公司技术中心河北唐山063002

通过优化合金成分、改进控轧控冷工艺等手段,成功开发出屈服强度在480~530 MPa,抗拉强度在560~630 MPa,延伸率在21%~25%,-20℃冲击功全部在200 J以上的Q420桥梁钢.对透射电镜下的析出相及金相显微组织中的晶粒尺寸进行相关统计计算,得... 详细信息

通过优化合金成分、改进控轧控冷工艺等手段,成功开发出屈服强度在480~530 MPa,抗拉强度在560~630 MPa,延伸率在21%~25%,-20℃冲击功全部在200 J以上的Q420桥梁钢.对透射电镜下的析出相及金相显微组织中的晶粒尺寸进行相关统计计算,得到各类强化贡献量数值,并对Q420桥梁钢的强化机制进行了分析.分析结果表明:在新开发的Q420桥梁钢中析出强化贡献量占全部强度的10%以下,而固溶强化量及细晶强化量分别占全部强度的54%及36%,因此确认420 MPa级桥梁钢的强化机制以固溶强化、细晶强化为主.

关键词：控轧控冷高韧性 420 MPa级桥梁钢强化机制强度计算