无料钟料流运动轨迹数学模拟

结合无料钟设备结构,分段建立了炉料运动轨迹方程,计算值与实测值吻合较好.分析了影响料流质心落点半径的诸因素,结论如下:溜槽倾角是决定料流质心落点半径的根本因素;料线、溜槽悬挂点至零料线距离、溜槽结构参数对料流质心落点半径影响较大;溜槽耐磨衬板的种类及溜槽角速度对料流质心落点半径具有一定的影响;而节流阀至溜槽悬挂点距离对其影响很小.     

Activity Calculation in Complex Metallurgical Molten Slag Systems Based on Regular Solution Model

 The activity of FetO is very important in ironmaking and steelmaking process. In order to predict the activity of FetO and optimize the operation conditions in ironmaking and steelmaking process, by application of regular solution model in molten slag systems, FeO-Fe2O3-SiO2 ternary system, FeO-Fe2O3-SiO2-CaO and FeO-Fe2O3-SiO2-NiO quaternary systems have been studied by the chemical equilibrium between H2/H2O gas mixture and liquid slag contained in solid iron. The values of interaction energy between cations concerning steelmaking slags have been determined by application of ferric-ferrous iron equilibrium and iron-ferric iron equilibrium. And then the activity of FetO can be calculated. The results show that the relative error is 39% in FeO-Fe2O3-SiO2 system and 18% in FeO-Fe2O3-SiO2-CaO system. The prediction of activities of FetO in the systems are in good agreement with the measurements and the regular solution model is valid for predicting the activity of FetO in complex molten slags systems. The activity of FetO in FeO-Fe2O3-NiO system have not been tested presently, and the calculated result can not be assessed.     

Research and Application of Flat Roll Technology in the Downstream Stands for CSP

  CVC mills are generally used in the whole stands of CSP (Compact Strip Product). Their special “s” curve of work roll contour and shifting strategy aimed at controlling strip shape, and the characteristics of continuous casting and rolling production, which make the work roll wear in downstream stands seriously uneven, and easily form abnormal transverse profile at the rolling end. As a result, CVC mill configuration in the downstream stands can not meet the profile and flatness control requirement for schedule free rolling, and bring some difficulties in profile and flatness control for the subsequent cold rolling. Based on the characteristics of the shape control system of CSP production line, and combined with the theory of flat roll technology, a kind of technology solution of using flat roll in the downsteam stands for CSP hot strip mills was proposed. At last, industrial test was carried out in the last stand of Masteel CSP, and good results were obtained.     

45钢双层辉光等离子渗Nb的组织及摩擦性能研究

 采用双层辉光等离子表面合金化技术对45钢进行表面渗Nb处理,用OM、SEM和XRD分析了渗Nb层的显微组织、化学成分及其相组成,测试了渗Nb合金层的显微硬度和表面耐磨性。结果表明：经过离子渗Nb处理后可获得约10μm的表面合金层;渗层中Nb含量随渗层深度呈梯度变化,渗层与基体结合牢固;XRD表明其表面形成Fe3Nb3C,Fe2Nb,NbC和Nb6C5等相。摩擦磨损试验表明：Nb的渗入使45钢基体摩擦系数由0.80左右降到了0.15,磨损失重仅为基体的18%,大大提高了耐磨性能。     

连铸矫直过程板坯角部横向裂纹数值分析

 连铸过程中板坯角部可能出现横向裂纹,这些裂纹严重影响着连铸坯的质量和产量。本文采用显式动力学有限元方法对连铸矫直阶段连铸板坯表层金属应力变化规律进行了模拟,分析了角部应力的变化规律,并对矫直过程中连铸板坯应力分布对角部横向裂纹的影响进行了讨论。研究结果对指导连铸生产具有重要的实际意义和理论意义。     

Thermal Expansion Behavior of Amorphous Fe-Si-B Alloys

 To study the thermal expansion of amorphous Fe Si B alloys, the amorphous Fe78Si9B13 and Fe735Nb3 Cu1Si135B9 and their crystallized alloys were detected using thermal dilatometer. The results indicate that at the same temperature, the relative length change (ΔL/L0) values of the two Fe based amorphous alloys decrease with increasing heating rate, but those of their crystallized alloys show an opposite trend. It is concluded that the effect of heating rate on the ΔL/L0 of amorphous and crystallized alloys is related to free volume and defects, respectively.     

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

 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 temperature, 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.     

X80钢焊缝再热后的组织与性能

针对西气东输二线X80高强度高韧性厚壁管线钢管双面埋弧焊接工艺特点,采用Gleeble1500热模拟试验和实物焊接试验,研究分析了内焊缝(一次焊缝)受到外焊(二次焊接)热循环后组织与性能变化情况。通过SEM、光学显微镜等进行了微观组织分析并做力学性能测试。结果表明,一次焊缝受到二次焊接热循环峰值温度在(α+γ)两相区范围时发生脆化,韧性降低22%;而一次焊缝在外焊二次热输入为20 kJ/cm时,冲击韧性最好;二次焊接在一次焊缝中形成了焊接临界粗晶区(WICHAZ),呈现粗大的条状铁素体,板条间为排列成行M-A组元或渗碳体,硬度由212HV5迅速增加到261HV5,韧性也随之变差。     

高炉高铝低钛渣的熔化性

在Al2O3的质量分数为15.14%~18.14%,TiO2的质量分数为2%~5%的范围内研究了普通高炉渣的熔化特性。应用正交试验方法,以水钢现场高炉渣为主要原料,适当配加分析纯的Ca(OH)2、MgO、SiO2、Al2O3和TiO2化学试剂调整炉渣的组成成分,采用炉渣熔化特性测试仪半球点法测定炉渣的熔化温度。试验结果表明:渣中碱度和Al2O3含量增加,炉渣熔化性温度升高;TiO2含量增加,炉渣的熔化性温度明显下降;适当提高渣中TiO2和MgO含量可避免因Al2O3含量升高而引起的熔化性温度上升;炉渣的熔化性温度在1 320~1 400℃之间,熔化性良好。     

提高包钢低硅烧结矿强度的试验研究

针对包钢低硅烧结矿强度差这一弊端,进行烧结杯试验探索混合料碱度、水含量、配碳量等工艺参数对包钢烧结矿转鼓强度、烧结速度、烧成率、组成和结构的影响。研究结果表明,当碱度为2.5、配碳量为3.8%(质量分数,余同)、水含量为8.4%、MgO含量为1.6%时能使SiO2含量为4.0%的烧结矿达到较高强度,并能满足高炉冶炼要求。     

Effect of Heat Input on Microstructure and Toughness of Coarse Grain Heat Affected Zone in Nb Microalloyed HSLA Steels

The influence of Nb on microstructure, mechanical property and the transformation kinetics of the coarse grain heat affected zone (CGHAZ) in HSLA steels for different heat inputs, has been investigated. When welded at higher heat inputs (100-60 kJ/cm), impact toughness values of the steel without Nb are much higher than those of the steel with Nb, and the lowest span is 153 J at 60 kJ/cm. But only a little higher values are observed at lower heat inputs (40-30 kJ/cm), and the highest span is 68 J at 30 kJ/cm. Dilatation studies indicate that continuous cooling transformation starting temperatures (Ts) of CGHAZ for the steel with Nb are approximately 15-30 ℃ which are lower than those of the steel without Nb at all heat inputs. For higher heat inputs, Nb in solid solution suppresses ferrite transformation and promotes the formation of granular bainite which has detrimental effect on impact tough-ness. For lower heat inputs higher Charpy impact energy values in the steel with Nb are associated with the formation of low carbon self-tempered martensite.     

TC4钛合金表面激光熔覆CoCrNi基合金涂层的温度场模拟

利用COMSOL对TC4表面激光熔覆制备CoCrNiMox及CoCrNi(WC)x高熵合金涂层的熔化与凝固过程的温度场进行模拟,建立了三维多物理场并存的瞬态模型,同时考虑了传热、流体传热、对流以及表面熔覆层生长过程,分析对比了扫描速度、激光功率等参数对添加不同含量Mo及WC的CoCrNi基合金温度场的影响。通过模拟结果可以得知,激光熔覆过程中熔池的主要驱动力为马兰戈尼力,提高Mo含量时会使涂层温度场的最大值降低,但同时速度场和压力场的最大值会上升。此外,使用CoCrNiMo2作为涂层粉末相比于熔覆CoCrNi(WC)2,会在温度场、速度场和压力场均观察到较低的数值;激光功率逐渐升高,激光熔覆产生的熔池的中心温度也随之升高,且熔池的宽度、深度也将有所升高;扫描速度逐渐升高时,熔池中心最高温度显著降低,熔覆层起始位置明显推迟,熔覆层厚度明显减少,熔池的几何尺寸变小且熔池底部形貌对称性变差。     

Improving the Toughness of Heat Affected Zone of Steel Plate by Use of Fine Inclusion Particles

There are two kinds of mechanisms of the improvement of Heat Affected Zone(HAZ) toughness with fine inclusion particles. One is to prevent the austenite grain growth during welding process with the aid of the pinning effect of fine particles. The other is to promote the Intragranular Ferrite growth during phase transformation process with fine particles. The oxide metallurgy technology with strong deoxidizers is developed in Baosteel. With the pinning effect of fine particles, after welding with high‐heat input of 400 kJ/cm, the average austenite grain size decreased to 61 µm in HAZ, the average energy absorbed value increased to 142 J for V notch Charpy test at 1653 K.     

Effect of Magnesium on Inclusion Formation in TiKilled Steels and Microstructural Evolution in Welding Induced CoarseGrained Heat Affected Zone

 Effects of Mg on the chemical component and size distribution of Ti bearing inclusions favored grain refinement of the welding induced coarse grained heat affected zone (CGHAZ), with enhanced impact toughness in Ti killed steels, which were examined based on experimental observations and thermodynamic calculations. The results indicated that the chemical constituents of the inclusions gradually varied from the Ti O+Ti Mg O compound oxide to the Ti Mg O+MgO compound oxide and the single phase MgO, as the Mg content increased from 0002 3% to 0006%. A trace addition of Mg (approximately 0002%) led to the refinement of Ti bearing inclusions by creating the Ti Mg O compound oxide and provided favorable size distribution of the inclusions for acicular ferrite transformation with a high nucleation rate in the CGHAZ, and a high volume fraction of acicular ferrite was obtained in the CGHAZ with enhanced impact toughness. Otherwise, a high content of Mg (approximately 0006%) produced a single phase MgO, which was impotent to nucleate an acicular ferrite, and a microstructure comprised of a ferrite side plate and a grain boundary ferrite developed in the CGHAZ. The experimental results were confirmed by thermodynamic calculations.     

Effect of Magnesium on Inclusion Formation in Ti-Killed Steels and Microstructurai Evolution in Welding Induced Coarse-Grained Heat Affected Zone

Effects of Mg on the chemical component and size distribution of Ti-bearing inclusions favored grain refinement of the welding induced coarse-grained heat affected zone (CGHAZ),with enhanced impact toughness in Ti-killed steels,which were examined based on experimental observations and thermodynamic calculations.The results indicated that the chemical constituents of the inclusions gradually varied from the Ti-O+Ti-Mg-O compound oxide to the Ti-Mg-O+ MgO compound oxide and the single-phase MgO,as the Mg content increased from 0.002 3% to 0.006%.A trace addition of Mg (approximately 0.002 %) led to the refinement of Ti-bearing inclusions by creating the Ti-Mg-O compound oxide and provided favorable size distribution of the inclusions for acicular ferrite transformation with a high nucleation rate in the CGHAZ,and a high volume fraction of acicular ferrite was obtained in the CGHAZ with enhanced impact toughness.Otherwise,a high content of Mg (approximately 0.006%) produced a single-phase MgO,which was impotent to nucleate an acicular ferrite,and a microstructure comprised of a ferrite side plate and a grain boundary ferrite developed in the CGHAZ.The experimental results were confirmed by thermodynamic calculations.     

Excellent Heat Affected Zone Toughness Technology Improved by Use of Strong Deoxidizers

Excellent Heat Affected Zone Toughness Technology Improved by use of Strong Deoxidizers (ETISD Technology) has been developed by Baosteel. When deoxidation of molten steel is conducted at the precisely controlled oxygen concentrations, the formation of the micro-meter inclusions and the nano-meter precipitates in the steel plate can be effectively controlled. During the welding process with high-heat input, the formation of acicular ferrite can be selectively promoted with the aid of micro-meter inclusions; the growth of γ grain can also be selectively restrained by the pinning effect of nano-meter precipitates. After welding with high-heat input of 400 kJ/cm, excellent heat affected zone toughness can be obtained for the steel plates with both of the above microstructures, and the average absorbed energy is greater than 200 J for V notch Charpy impact test at -20℃ .     

激光熔覆工艺及熔覆材料进展

激光熔覆技术在目前材料表面改性技术中应用较广泛。本文概述了激光熔覆技术及工艺方法,介绍了激光熔覆材料分类及特点,并展望了激光熔覆技术的发展前景。     

低合金钢焊接热影响区的静载断裂特性

 低应力破坏是焊接结构常见的断裂形式之一,为确定其影响因素,采用插销法焊接试验和扫描电镜断口观察,研究了低合金钢焊接热影响区的静载断裂特性。试验结果表明,为防止焊接热影响区产生低应力断裂,采用预热措施是十分有效的;预热80℃以上时,断裂强度与母材强度相接近。断口观察表明,不预热时绝大部分为结晶状断口,微观上呈现氢致沿晶断裂和氢致准解理断裂;预热时绝大部分是纤维状断口,微观上呈韧窝状。     

08MnNiVR储油罐钢模拟焊接热影响区组织与韧性研究

利用焊接热模拟、示波冲击韧性和光学金相试验,研究了不同焊接热循环对鞍钢08MnNiVR储油罐钢板热影响区组织与性能的影响。试验结果表明,08MnNiVR钢板粗晶区在低热输入时具有很高的韧性且组织以粒状贝氏体为主,随着热输入的增加,组织向块状铁素体和珠光体转变,粗晶区的裂纹扩展功降低,韧性恶化。