大型磨机高铬铸铁衬板的研制

2005年我院耐磨耐热材料厂承接江苏嘉新京阳水泥有限责任公司一套∮4.2 m× 13 m水泥磨机衬板的生产订单,衬板外形结构如图1所示.大型磨机中,磨内磨球具备较大的冲击能量,这就要求磨机衬板需要高的冲击韧性,通常国内大磨机衬板采用中碳合金钢制造,以保证衬板的安全使用.     

中碳合金钢用手电厂磨煤机衬板锤头试验研究

本文指出高锰钢用于电厂磨煤球磨机筒衬板存在既不耐磨又产生变形的问题。ZG50Mn2耐磨性差,研制的ZG42CrMn2SiMoRE成功地运用于Φ3.8m球磨机筒衬板及锤击式磨煤机锤头,安全可靠、耐磨性好,不产生变形。     

高碳珠光体钢在大型半自磨机筒体衬板上的应用

本文介绍了铜矿磨矿用大型半自磨机的使用工况和使用环境，以及大型半自磨机筒体衬板的材质、组织和性能的选定。衬板材质为CrMoNi高碳钢，组织为珠光体+少量二次碳化物，硬度为35～42 HRC，无缺口冲击韧性≥60 J/cm²。结合衬板结构的优化设计，铜矿用大型半自磨机筒体衬板的使用寿命可稳定在4个月，重量磨损率为44.44%。确定了大型半自磨机筒体衬板的磨损失效机制，除矿石产生的磨粒切削、疲劳磨损外，还存在矿石浆料产生的腐蚀磨损。分析了影响大型半自磨机筒体衬板使用寿命的因素，为大型半自磨机衬板的生产、使用和寿命提高提供了参考。     

大型半自磨机衬板成分优化模拟分析

针对现行0.4%Mo含量的ZG70Cr3NiMo材质半自磨机衬板淬硬层偏浅的问题,在不改变冷却方式的基础上,利用计算机模拟技术探讨通过成分调整增加淬硬层深度的可行性。针对ZG70Cr3NiMo半自磨衬板用钢,该研究采用正交试验的方法,分析Mo、Si、Cu、Mn等不同合金元素及其含量对材料淬透性的影响,探讨了各合金元素配比和合金力学性能的关系,最终确定最佳Mo含量以及其他合金元素的种类及含量。研究结果表明,C0.7Si0.8Mn0.9Mo0.7Ni0.5Cr3.2Cu0.6合金成分为最优配比,性价比最高,其马氏体转变温度Ms为147℃,淬火硬度为59.4~59.5 HRC;对比现行成分,优化成分的淬透性得到极大的提升,同时获得优良的力学性能。     

ZG40Mn2Si1RE钢衬板热处理工艺的金相控制

ZG40Mn2Si1RE是用我国富产合金元素硅、锰、稀土生产的一个钢种.用该钢制做φ3m以下球磨机衬板、隔仓板以及篦板,使用性能很好.该钢强韧性高、耐磨性好,能适应球磨机工况条件的需要.     

冷却介质对ZG30CrMn2Si2NiMo组织和力学性能的影响

研究了不同冷却介质对ZG30CrMn2Si2NiMo铸钢力学性能及组织的影响.试验结果表明,奥氏体化后空冷ZG30CrMn2Si2NiMo组织为板条贝氏体型铁素体和残余奥氏体组织,奥氏体化后淬火ZG30CrMn2Si2NiMo组织为板条马氏体、贝氏体型铁素体和残余奥氏体组织.ZG30CrMn2Si2NiMo获得板条马氏体、贝氏体型铁素体和残余奥氏体组织时,具有良好的力学性能.     

ZG31Mn2Si硅锰钢圆锥衬板组织与性能研究

通过感应炉熔炼和吹氩精炼制备了ZG31Mn2Si,研究了ZG31Mn2Si的熔炼工艺及热处理工艺对其显微组织和硬度及冲击韧度的影响。结果表明:采用890℃正火+890℃水淬+200℃低温回火的热处理工艺,钢的显微组织为细小的板条状马氏体和少量呈薄片状分布在马氏体周围的残余奥氏体。其硬度和冲击韧度得到最佳匹配值,分别为47 HRC和41.25 J/cm2,基本达到了圆锥衬板的使用要求,完成了实验的预定目标。     

球磨机衬板使用寿命的研究

球磨机是国内外火电厂、水泥、矿山、化工、冶金等行业生产中主要的粉碎研磨设备,而球磨机衬板是用来保护筒体,使筒体免受研磨体和物料直接冲击和磨擦,同时也可利用不同形式的衬板来调整研磨体的运动状态,以增强研磨体对物料的粉碎作用,提高磨机的粉磨效率.通过改变球磨机衬板的结构形状,消除衬板在铸造过程中存在的缺陷,从而使村板的使用...     

球磨机衬板用ZGCr13SiMo钢的研制与应用

针对水泥磨机简体高锰钢衬板磨损造成破坏问题,研制了一种ZGCr13SiMo钢.经过河北冀东水泥厂φ4.5 m×15.11 m水泥磨第二仓使用和工业性对比试验,取得了很好效果,其使用寿命达20年以上.     

水泥工业管磨机用磨球衬板常用材质的评述

在简介磨球、衬板磨损和失效的基础上,评述了国内外水泥工业管磨机所用磨球、衬板的常用材质。为减少磨球的碎裂、失圆、磨耗和衬板的磨损、断裂、变形,对磨球、衬板材质的耐磨性和韧性的最佳配合以及材质的选用等进行了讨论。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。