花键轴的中频感应热处理

42CrMo钢花键轴由于形状特殊,其表面中频淬火有一定难度。通过特殊结构感应器设计和表面淬火工艺过程的优化,成功地实现了花键轴局部表面的中频感应淬火,达到了花键轴的技术要求。     

基于ANSYS的多点式中频感应淬火温度场有限元模拟

研究了用多个淬火感应器对半径较大的回转体表面进行中频感应淬火的作用机理,针对较大半径的回转体表面的多点式感应淬火工艺进行参数设计,建立了多点式感应淬火过程的电磁场和温度场的非线性偏微分方程组。利用有限元分析ANSYS软件来模拟多点式中频感应加热过程,其中对激励电流用表格法加载来近似地替代实际旋转工件周期性的感应淬火,从而得到了工件温度场随时间的变化规律以及最终工件的温度场分布。结果表明,多点式中频感应淬火改善了较大半径的回转体的凹槽表面淬火过程,可以达到对感应淬火工件淬硬层的要求,解决了由于不同时感应淬火所导致的软带问题。     

铁路车轴表面强化技术研究与应用

车轴是列车转向架的核心部件之一,引发车轴失效的表面损伤形式主要包括腐蚀、微动磨损和外物致损。表面强化可改善车轴表面完整性,进而抑制裂纹萌生和延缓裂纹扩展,以提高车轴疲劳强度并延长剩余寿命。车轴表面强化技术主要包括滚压、喷丸及表面感应淬火。首先,概述了国内外普速和高速列车车轴表面强化技术的基本原理:滚压和喷丸等物理强化方式使车轴表面塑性变形硬化并引入残余压应力,表面感应淬火通过马氏体相变提高车轴表面强度并引入残余压应力。然后,重点综述了上述3种表面强化技术的研究进展及其在当前车轴制造过程中的应用,其中,深度滚压是车轴表面强化的主要方式,表面感应淬火主要应用于部分高铁车轴上,而喷丸在车轴上的应用尚少。最后,从经济性和安全性的角度对比了车轴表面强化技术的优劣:喷丸强化深度有限,不足以提高车轴剩余寿命;中碳钢车轴表面淬火方案在淬硬层深度和残余应力大小方面均优于合金钢车轴滚压方案。基于损伤容限设计的评价为未来车轴表面强化技术的研究和应用提供了借鉴。     

弹簧片单面中频淬火工艺及其感应器设计

为解决内燃机车运行过程中柴油机弹性联轴器的弹簧片与花键轴啮合使用时因硬度不均而断裂的问题,采用中频感应淬火工艺代替原激光表面淬火工艺,设计了新的中频淬火感应器,并制定了相应的单面感应淬火工艺,装车后运用效果良好。     

50Mn钢凸轮轴的中频感应淬火

凸轮轴是柴油机的重要传动件之一,要求根据所采用的材料进行渗碳淬火或表面淬火,以提高其表面硬度和耐磨性。50Mn钢凸轮轴采用BVH-1000双工位中频淬火机床、仿形感应器和专用夹具等设备,以及10％～15％AQ251聚合物水溶液进行感应淬火。结果,凸轮轴的表面硬度、硬化层深度分布和显微组织均达到了要求,生产成本明显低于进行渗碳淬火的20Cr钢凸轮轴。     

中频感应淬火的S48C钢齿轮的弯曲疲劳性能研究

齿轮是推土机的重要传动件。弯曲疲劳是齿轮的主要失效形式。对经调质处理的中碳S48C钢齿轮进行了不同工艺的中频感应淬火和170低温回火,并对部分齿轮进行了喷丸处理。采用MTS Landmark 250 kN型电液伺服试验机测定了齿轮的弯曲疲劳寿命,并检测了轮齿截面的硬度分布和显微组织。结果表明,中频感应淬火工艺对齿轮的弯曲疲劳寿命和硬化层深度有影响,喷丸处理可明显提高齿轮的弯曲疲劳寿命。     

42CrMo钢驱动轮轴的感应热处理

利用GCK10150感应淬火机床(KGPS250/8000电源)和自主研发设计的感应器对某型号大轮拖拉机(≥160马力)42Cr Mo钢驱动轮轴进行表面淬火工艺试验,借助磁粉探伤仪、洛氏硬度计、金相显微镜和静扭试验机对感应淬火后的42Cr Mo钢驱动轮轴的组织与性能进行了分析。结果表明,42Cr Mo钢驱动轮轴感应淬火后的淬硬层深满足花键根部3.25~8.25 mm、光轴表面7~12 mm、键槽≥2 mm,硬度满足淬火硬度52~57 HRC、调质硬度262~302 HBW,并且淬硬层连续,同时零件表面不存在烧伤、裂纹等缺陷。42Cr Mo钢经调质+感应淬火+200℃×2 h回火后的抗扭性能最高。     

42CrMo钢驱动轮轴的感应热处理工艺

利用GCK10150感应淬火机床（KGPS250/8000电源）和自主研发设计的感应器对某型号大轮拖拉机（≥160马力）42CrMo钢驱动轮轴进行表面淬火工艺试验,借助磁粉探伤仪、洛氏硬度计、金相显微镜和静扭试验机对感应淬火后的42CrMo钢驱动轮轴的组织与性能进行了分析。结果表明,42CrMo钢驱动轮轴感应淬火后的淬硬层深满足花键根部3.25～8.25 mm、光轴表面7～12 mm、键槽≥2 mm,硬度满足淬火硬度52～57 HRC、调质硬度262~302 HBW,并且淬硬层连续,同时零件表面不存在烧伤、裂纹等缺陷。42CrMo钢经基体调质+感应淬火+200 ℃×2 h回火后的抗扭性能最高。     

可控硅在双频（低中频）感应淬火机上的应用

介绍了国产双频,低中频,感应淬火机上可控硅将工频电能变频为低中频电能的变频过程,国产双频,低中频,感应淬火机成功地应用于冷轧工作辊热处理的情况,同时与比利时OSB双频,工中频,感应淬火机进行比较.结果表明,国产双频(低中频)感应淬火机达到进口的设备的性能,获得冷轧辊所需工艺质量目标.     

GF6涡轮轴中频淬火开裂分析及改进

对涡轮轴感应淬火表面裂纹进行了分析,通过工艺试验优化了感应淬火工艺参数.结果表明,预处理后存在上贝氏体及组织不均匀是导致涡轮轴感应淬火开裂的主要原因.采用降低加热功率、延长加热时间的中频淬火工艺来降低加热速度,能有效避免淬火开裂.     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

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.     

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.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.