TbDyFe超磁致伸缩材料机电耦合特性实验研究

主要讨论TbDyFe超磁致伸缩材料电磁与机械耦合特性实验的若干问题,建立了电磁与机械耦合系统的物理模型并应用阻抗分析方法得到了相应的等效电路．设计制作了实验装置,测定了在电磁场与应力场共同作用下TbxDy1-xFe2-s三元稀土合金超磁致伸缩棒的机电耦合系数与电磁与机械耦合系统振动频率等．所得结果为进一步研制稀土超磁致伸缩换能器提供了重要的实验依据．     

利用射钉法测量240mmx240mm铸坯凝固坯壳厚度

利用射钉法测定了连铸机生产240mm×240mm断面35CrMoA、20CrMoA、GCr15、60Si2MnA四个钢种的铸坯凝固坯壳厚度,并根据凝固定律计算了其液相穴长度和综合凝固系数;针对240mm×240mm方坯选择固相率0.70、0.75进行计算得出F-EMS在不同拉速条件下的电磁搅拌位置,分析了工艺参数对连铸机凝固系数的影响,提出的工艺优化措施为:改变电磁搅拌位置,F-EMS位置修正为根据高碳钢GCr15、60Si2MnA来安装,35CrMoA,20CrMoA,GCr15和60Si2MnA四钢种拉速值分别调整为0.80、0.81、0.78、0.80 m/min。工艺优化后铸坯质量得到明显改善,中心偏析级别≤0.5合格率由原来≤40%提高到100%,中心疏松级别≤1.5合格率由原来≤50%提高到≥90%。     

超磁致伸缩材料的研究新进展

近年来,稀土超磁致伸缩TbDyFe材料的研究进展迅速,既有新的研究方向如材料力学性能、合金的凝固过程、磁畴取向的分布、组分处于准同型相界的合金的性能等,也有传统的如热处理时施加高磁场及应力处理、新热处理方法等方面。此外,科研人员不断开发出新的稀土超磁致伸缩材料合金体系,即不同元素对TbDyFe体系的部分取代与添加,主要有Pr、Nd、Sm、Gd、Ho和Er等稀土元素及第八族的Co元素。     

链轨节用钢15B36Cr的开发与试制

淮钢采用90 t顶底复吹转炉-LF-RH-200 mm×200 mm连铸-连轧工艺流程试生产了2炉Φ60 mm链轨节用钢15B36Cr(/%:0.30～0.37C、0.15～0.30Si、1.20～1.50Mn、≤0.040P、≤0.0505、0.20～0.40Cr、≤0.25Ni、≤0.35Cu、≤0.06Mo、0.0005～0. 0030B)。通过加严影响淬透性化学成分,控制出钢碳≥0.08%,转炉有效挡渣和下渣检测系统控制下渣,LF炉铝粒和电石渣面脱氧,RH最低真空度处理20～30 min,结晶器电磁搅拌、末端电磁搅拌和连铸低过热度保护浇铸等工艺措施,15B36Cr钢的化学成分稳定控制在内控范围内,除了B粗以外,其他类型非金属夹杂物级别全部控制在1.0以内,淬透性控制在较窄的范围内,试制钢种关键技术指标达到客户和预期设计要求。     

Nb-V微合金化含Cu高强度耐候钢的开发和耐蚀性

通过合适的成分设计和控轧控冷工艺开发出一种综合力学性能优异的Nb-V微合金化含Cu高强度耐候钢（/%:≤0.12C,≤0.40Si,≤1.40Mn,≤0.020P,≤0.010S,0.40～0.45Cr,0.25～0.35Cu, ≥0.020Al,0.02～0.03Nb,0.02～0.03V）,并对其耐蚀性能进行了研究。该高强耐候钢组织由铁素体、珠光体和贝氏体组成,抗拉强度高达697 MPa,屈强比为0.73,断后伸长率为24.6%, -40℃纵向冲击功为70.6 J。盐雾及周期浸润试验结果表明,该钢耐蚀性能显著优于Q345B,其锈层主要由Fe₃O₄、α-FeO（OH）和γ-FeO（OH）构成,且随着时间增加,Fe₃O₄相对含量增加,α-FeO（OH）变化较小,γ-FeO（OH）减少。     

Preparation and thermoelectric properties of ternaryrare earth sulfide γ-Ce3-xEuxS4

The effect of Eu-substitution on the density and thermoelectric properties of ternary sulfide Ce3-xEuxS4 (0≤x≤0.8) compacts was investigated. Ce3-xEuxZ4 powders were prepared via the sulfurization of the oxide using CS2 gas at 1473 K. The pressureless sintered Ce3-xEuxS4 compacts in the atmosphere were crystallized in the γ-phase. The density of the Ce3-xEuxS4 compacts increased with the increas-ing of Eu-substitution. Eu-substitution yielded a higher Seebeck coefficient and lower electrical resistivity. The highest value of the thermoe-lectric power factor of 1.41×10-4 W/K2m was obtained for the Ce2.2Eu0.8S4 compact at 673 K. It indicated that Eu-substitution was effective for improving thermoelectric properties of Ce3-xEuxS4.     

弧形连铸机生产S355NL/Q355NE钢Φ1200 mm连铸圆坯的工艺实践

Φ1200 mm S355NL/Q355NE钢(Ceq 0.38～0.41)连铸圆坯的生产流程为100 t KR-BOF-LF-RH-R18 m连铸。采用全保护浇注、精确冷却工艺、三段式电磁搅拌、缓冷工艺等技术措施,过热度控制在15～45℃,拉速为0.14～0.20 m/min,电磁搅拌300 A/2 Hz,二冷比水量0.20 L/kg,圆坯入坑缓冷时间≥72 h,出坑温度≤300℃。检测结果表明,[O]≤0.0018%、[H]≤0.00008%;铸坯中心疏松≤1.5级、中心裂纹≤1.5级、缩孔≤0.5级;全截面碳含量极差≤0.07%;圆坯成分、低倍、表面均满足标准要求。圆坯经用户锻造成壁厚450～550 mm的风电法兰后,夹杂物、力学性能、内部探伤等质量指标检测结果,完全符合技术规范及用户使用要求。     

末端电磁搅拌参数对帘线钢72A铸坯中心碳偏析的影响

帘线钢72A(%:0.71～0.72C、0.50～0.60Mn、0.22～0.30Si、≤0.010P、≤0.008S)的冶炼工艺流程为铁水预处理-LD-LF-RH-CC-200 mm×200 mm连铸。在连铸时钢水过热度10～20℃,拉速0.98 m/min,二冷比水量0.32 L/kg,结晶器冷却水220 m³/h,结晶器电磁搅拌1.5 Hz、500 A的条件下进行了末端电磁搅拌(F-EMS)的工艺研究。结果表明,当离钢液弯月面8 m处以18 Hz、450 A进行F-EMS,可使帘线钢72A铸坯的中心碳偏析指数≤1.05。     

Magnetic and magnetostrictive properties of amorphous TbFe/FeAl multilayer thin film

Exchange coupling multilayer thin films, which combined giant magnetostriction and soft magnetic properties, were of growing interest for applications. The TbFe/FeAl multilayer thin films were prepared by dc magnetron sputtering onto glass substrates. The microstructure, magnetic, and magnetostrictive properties of TbFe/FeAl multilayer thin film was investigated at different annealing temperatures. The results indicated that the soft magnetic and magnetostrictive properties for TbFe/FeAl multilayer thin film compared with TbFe single layer film were obviously improved. In comparison with the intrinsic coercivity JHc of 59.2 kA/m for TbFe single layer film, the intrinsic coercivity JHc for TbFe/FeAl multilayer thin films rapidly dropped to 29.6 kA/m. After optimal annealing (350 ℃×60 min), magnetic properties of Hs=96 kA/m and JHc=16 kA/m were obtained, and magnetostrictive coefficient could reach to 574×10-6 under an external magnetic field of 400 kA·m-1 for the TbFe/FeAl multilayer thin film.     

共赢思维在凉山矿业跨越发展中的应用探讨

共赢思维是近年市场经济发展中许多商家及经济学家总结出来的经验。凉山矿业股份有限公司制定的“128”跨越式发展战略和“十一五”规划,以人为本,以资源为核心,从务实到务虚,都体现了企业发展的动力与后劲,如何处理好竞争、合作与共赢的关系,本文提出了一些粗浅的看法。     

交替变向电磁场对稀土镁球铁球化衰退的影响

自行研究和设计了交替变向电磁场装置。将采用稀土镁球化处理后的铁水，经不同保温时间后，分别在重力场和电磁场中凝固，利用对比试验的方法考察电磁场对球墨铸铁球化衰退的影响规律。结果表明：交替变向电磁场可加速球化元素镁和稀土的脱S脱O作用，使电磁场中凝固的球墨铸铁S，O含量相对较低，从而抑制了球墨铸铁的球化衰退。     

汽车曲轴用含硫易切削钢C38N2硫化物控制的工艺实践

C38N2钢(/%:0. 36～0.40C,0. 50～0.65Si,1. 40～1. 55Mn,≤0. 025P,0. 010～0.040S,0.10～0.25Cr,≤0.01Al,0. 015～0.020N)的生产工艺流程为120 t BOF-LF-RH-410 mm×530 mm连铸坯-连轧成Φ170 mm材。统计分析了精炼渣碱度(2. 0～5. 5)、成品钢中Ca含量(0～0. 075%)、中间包覆盖剂碱度(5. 94和1.70)、二冷水(0. 14～0. 24 L/kg)和结晶器搅拌电流(250 A和100 A)对钢中硫化物的影响,通过采用2～3低碱度精炼渣,控制[Ca]/[S]>0.03,使用1.70碱度中间包覆盖剂,二冷水0.24 L/kg,结晶器搅拌电流100 A等工艺措施,使钢中A类细系硫化物≤2.5级的比率从工艺改进前80%提高至95%,钢中小尺寸、弥散分布的球形或纺锤形硫化物明显增多。     

含Nb不锈钢中厚板中间裂纹分层原因分析及控制

针对含Nb不锈钢热轧中厚板出现的中间裂纹分层以及力学性能不合问题,通过金相观察、扫描电镜、相分析和力学性能检测等手段对中间裂纹分层以及力学性能不合原因进行研究。结果表明,Mo、Nb在凝固过程中偏析严重、形成σ相和Z相(CrNbN)是产生热轧中厚板中间裂纹分层以及力学性能不合的主要原因。通过降低Nb含量,优化热处理制度,降低钢液过热度,确定合理冷却制度,添加电磁搅拌工艺,可以有效地减小中间裂纹分层的发生并提高低温冲击韧性。     

Influence of Frequency and Bias Current on Asymmetrical GMI Effect in Co71.8 Fe4.9 Nb0.8 Si7.5 B15 Amorphous Glass-Covered Wires

The Co71.8Fe4.9Nb0.8Si7.5B15 amorphous glass-covered wires（AGCW）are prepared by the Taylor-Ulitovsky technique.The frequency dependence of asymmetrical giant magneto-impedance（AGMI）effect in amorphous glass-covered wires annealed by 70 mA DC current is here presented.The resistance R and the reactance X have been measured,respectively.The real part R and the imaginary part X of impedance play an important role at high frequency and low frequency,respectively.The influence of DC bias current from Ib=0 mA to Ib=5 mA at 30 MHz on the GMI effect in the glass-covered wires annealed by 70 mA DC current is investigated.The asymmetry becomes the largest around Ib=1 mA,and finally decreases for the larger bias current Ib=5 mA.The maximum ΔZ/Z ratio of 310% is observed at 58 MHz under 1 mA bias current.     

Preparation and Performance of Al2 TiO5 -TiO2 -SiO2 Honeycomb Ceramics by Doping Rare Earth

A preferable honeycomb ceramics of Al2TiO5-TiO2-SiO2 doped by CeO2 and Er2O3 with high performance was prepared by means of extrusion molding and the effects of CeO2 and Er2O3 on the mechanical strength, thermal stability, and sintering temperature of ATS ceramics were mainly investigated. The experimental results and the microscopic analysis by scanning electron microscope, X-ray powder diffxaction, and TG-DSC showed that adding CeO2 and Er2O3 into ATS could prohibit the growth of their crystal grains and make their size uniform, which finally decrease its sintering temperature, and also enhance its mechanical performance as well as thermal stability. After the reforming, ATS doped by 0.5% CeO2 ＋0.5% Er2O3 was sintered at 1250 ℃, its bending strength reached to 177A MPa and thermal expansion coefficient was 3.8 ~ 10^-6/℃ at 25 - 1000℃, which provided a promising basis of making monolithic honeycomb catalyst of deNOx.     

Research on Key Metallurgical Technology of 350Km/h High‐Speed Rail Steel

Requirements like higher cleanliness and better quality of casting blooms are proposed for 350km/h higher speed rail steel. Present paper focuses on technical measures on improving the steel cleanliness and strand quality of 350km/h high‐speed rail steel in Panzhihua Iron & Steel Group Company. By means of series of packaging technology like dephosphorization in BOF, ladle refining, mold electromagnetic stirring and dynamic soft reduction, dephosphorization rate cleanliness and morphology control are greatly improved, with [S]≤0.015%, [P]≤0.025%, [H]≤1.5 × 10^?6, Al_s ≤ 0.004%, T[O] ≤20 × 10^?6, the grade of central porosity and segregation ≤1.0, the grade of central crack and middle crack ≤0.5, index of central carbon segregation ≤1.05, severity level of type‐A and type‐B inclusions ≤2.0 and 1.0, respectively. The optimized process meets the technical requirements on producing 350 km/h high‐speed rail steel and stable production is realized.     

冷轧铝板摩擦系数模型建立

通过电测法实验,运用Bland-Ford公式,对铝板冷轧过程的摩擦系数进行了研究测定,建立了摩擦系数的数学模型.实践证明,模型精度很高.     

120t LD-RH-LF CSP流程生产W600无取向硅钢的工艺实践

马钢一钢轧总厂通过120 t LD(顶底复吹)-RH-LF-70 mm和90 mm薄板连铸-连轧工艺生产W600无取向硅钢。通过控制转炉出钢[C]0.03%～0.04%,RH真空脱碳至0.002 5%C,RH脱碳前补加FeP,LF二次精炼脱硫,RH-LF调整Als等工艺措施控制钢中C≤0.005%、P 0.050%、Als 0.20%、N≤40×10^-6,所生产的W600钢铸坯成分均匀,钢板的力学性能满足技术要求。     

胶结充填体矿柱结构可靠性设计方法

胶结充填体矿柱广泛应用于地下矿山，矿柱结构的稳定性直接关系到采矿生产安全，胶结充填体矿柱结构可靠性设计日益受到重视和普遍应用。传统的安全系数法不能考虑影响胶结充填体矿柱结构稳定性因素的随机性和离散性，因而其结论具有很大的局限性。变异安全系数法可以可靠性理论为基础，充分考虑胶结充填体矿柱结构稳定性影响因素的随机性及其离散程度，计算结果更具指导性。章从胶结充填体矿柱力学分析入手，分析了安全系数法的局限性，详细介绍了变异安全系数法及其用于胶结充填体矿柱结构可靠性设计的方法。     

渗透系数对饱和土强夯效果影响的数值模拟

采用FLAC3D数值软件建立考虑强夯非线性、大变形和流固耦合特性的饱和土地基三维强夯计算模型;应用所建立的计算模型进行渗透系数在0.0001～0.1 cm/s范围内的数值模拟计算,分析渗透系数变化时的位移、孔压、密度和塑性体积的变化特性.从数值计算结果证明了饱和土地基夯击瞬间加固效果与渗透性能有关,渗透系数越大,瞬间夯击效果越好.