奥贝球铁齿轮弯曲疲劳强度的试验研究

对各种状态的奥贝球铁齿轮的弯曲疲劳强度进行了试验研究.结果表明：（1）6DF1柴油机奥贝球铁曲轴正时齿轮的弯曲疲劳强度完全能满足设计要求,安全系数可达3.56倍.（2）适当减小齿轮与曲轴的热套过盈量有利于提高奥贝球铁齿轮的极限弯曲疲劳载荷;本试验的奥贝球铁齿轮齿根脱碳层未磨掉的比齿根脱碳层磨掉的极限弯曲疲劳载荷反而高,且其效果比减小齿轮热套过盈量更明显.（3）喷丸强化能使奥贝球铁齿轮极限弯曲疲劳载荷提高31.7%～47.6%.     

奥贝球铁齿轮在柴油机上的应用研究

研究了不同等温温度及Mn、Si、Cu、Mo对奥贝球铁组织和力学性能的影响,讨论了奥贝球铁加工硬化对机加工性能的影响。同时,奥贝球铁齿轮代替40Cr调质钢齿轮进行装机试验,对降噪声和耐磨性进行了测试。结果表明,奥贝球铁齿轮与40Cr调质钢齿轮相比,力学性能高,柴油机整机噪声下降1.92dB,齿轮侧噪声下降5.3dB,奥贝球铁齿轮经过45h磨合后,在标定工况下连续运转200h,齿轮无异常磨损,齿轮间隙离极限间隙还有0.13mm的余量,所以其摩擦磨损性能合格,所生产的奥贝球铁齿轮满足设计使用要求。     

奥贝球铁齿轮在小四轮拖拉机上的应用

用奥贝球铁代替２０ＣｒＭｎＴｉ钢生产小四轮拖拉机减速齿轮具有成本低、质量稳定、节约原材料及易于推广应用等优点．本文详细论述了奥贝球铁齿轮的铸造与热处理工艺     

非合金奥贝球铁淬透性研究

结合奥贝球铁齿轮的应用研究,较系统地介绍了非合金奥贝球铁不同温度等淬的淬透性研究。解决了非合金奥贝球铁不同温度等淬的淬透层浓度及硬度问题,对奥贝球铁材料的生产应用具有一定的指导意义。     

汽车发动机奥贝球铁齿轮等温淬火工艺研究

针对某厂汽车发动机奥贝球铁齿轮材料，研究了等温淬火工艺对奥贝球铁组织和性能的影响。结果表明：经８８０℃奥氏体化＋３２０℃等温淬火处理，可获得上贝氏体／下贝氏体的混合组织。该组织具有优良的综合机械性能，满足了汽车发动机齿轮的技术要求。     

农用耕整机奥贝球铁传动齿轮的试验研究

根据耕整机的工况,对其变速箱奥贝球铁传动齿轮的生产工艺及装机应用作了研究;结果表明,可代替40Cr钢齿轮。     

奥贝球铁齿轮热处理工艺的研究

介绍了采用奥贝球铁生产拖拉机末端从动齿轮的铸造及热处理工艺试验情况，着重探讨了热处理工艺参数对奥贝球铁各项力学性能指标的影响，针对小四轮拖拉机末端从动齿轮优选出了合理的热处理工艺。     

奥贝球铁齿轮性能稳定性的影响因素分析

分析了Cu-Mo合金奥贝球铁齿轮性能稳定性的影响因素,提出了相应的措施,制定了Cu-Mo奥贝球铁齿轮质量控制的基本原则。     

金属型铸造奥贝球铁链轮的生产实践

近年来,奥贝球铁由于具有优良的综合力学性能而受到人们的广泛关注.用奥贝球铁代替锻钢制造齿轮的研究越来越多,现已进入实用阶段.鉴于奥贝球体在齿轮上的应用,决定尝试铸造奥贝球铁链轮毛坯代替锻造毛坯件.目前,中州分公司链轮规格较多且用量大,锻造毛胚进货成本高,加工量大.经过实践证明,采用金属型铸造生产奥贝球铁链轮毛坯,技术上可行,成本低,获得了明显的经济技术效益.     

等温淬火球墨铸铁的滑动磨损

研究了奥贝球铁，下贝球铁及与其基体组织相同的钢的滑动磨损性能。实验结果表明：在一定条件下，石墨对等温淬火球铁耐磨尾无补而有损，由于奥贝球铁的转折载荷随摩擦速度的提高而增大，当转速为９８０ｒ／ｍｉｎ，载荷〉６８．６Ｎ，等温淬火球铁的耐磨性优于钢。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.