国外汽车零件感应淬火技术

本文重点介绍欧美日等国的汽车半轴、曲轴、凸轮轴、转向齿条、等速万向节、气缸套和汽车齿轮等七种零件的感应淬火工艺、淬火机床、新材料研制和中高频电源设备方面的情况。     

凸轮轴连续感应淬火的质量问题及解决措施

凸轮轴在连续感应淬火中,容易出现淬硬层深度不均匀、凸轮升程部位过热、基圆软带、棱角部位开裂以及热影响产生的软带等质量问题。为了解决这些问题,在感应器结构、工件移动速度、旋转速度、电参数选择、加热位置及加热延时、加热和冷却方式等方面,进行了全方位的设计。结果表明,通过淬火工艺的改进,解决了凸轮轴感应淬火中的这些质量问题,保证了产品质量和生产效率。     

国外汽车零件感应淬火技术

本文重点介绍欧美日等国的汽车半轴曲轴，凸轮轴，转向齿条，等速万向节，气缸套和汽车齿轮等七种零件的感应淬火工艺，淬火机床，新材料研制和中高频电源设备方面的情况。     

船用柴油机凸轮轴中频淬火工艺数值模拟分析

针对凸轮轴零件中的凸轮部位感应淬火工艺淬硬层不均匀、局部残余应力过大的问题,采用SYSWELD软件中的热处理模块,建立凸轮感应淬火工艺有限元模型,基于可变换热系数及奥氏体动力学理论,对GCr15凸轮轴中频感应淬火过程进行仿真分析,获得淬硬层厚度、硬度以及凸轮残余应力场分布规律。结果表明,在加热功率为110~120 kW,频率为5 600 Hz,加热时间为6 s时,过渡轮廓面淬硬层最薄处为1.34 mm,表面硬度均达到700 HV以上,桃尖表面残余压应力为-50 Pa,过渡轮廓面达到-350 MPa。     

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。     

冷硬合金铸铁凸轮轴的生产

凸轮轴长期在恶劣的环境中工作，它要求具有耐磨性、足够的硬度和韧性等综合力学性能，并还要求耐一定的高温。同冷硬合金铸铁凸轮轴相比，其它凸轮轴的生产工艺或经高温淬火、中频淬火等表面处理工艺，使凸轮轮工作面形成一层2～3mm厚的马氏体，其工艺生产过程比较复杂，工序多，周期长，成本也高。我们通过采用一定的工艺措施（在凸轮工作面放置冷铁，添加合金元素），得到合格的凸轮轴。1生产条件与方法冷硬合金铸铁凸轮轴轮廊尺寸为50X480，分析试样直接在本体上截取。熔炼设备为200kg无芯中颇感应电炉，炉料采用本溪生铁Z15、废铁料、…     

凸轮轴超音频淬火工艺的改进

一种摩托车发动机用凸轮轴,材料为QT600-3球墨铸铁,要求其工作面具有足够的硬度和耐磨性。采用局部超音频感应淬火能达到凸轮轴的性能要求,但凸轮部位易过热、烧熔或开裂。改进淬火操作方法后,这些问题得到了解决。     

高强度球铁凸轮轴淬火裂纹的研究

高强度球铁凸轮轴,在进行凸轮表面感应淬火过程中,凸轮旁边的退刀槽在淬火热应力的作用下,极易产生淬火裂纹。通过控制铸件合金成分,改进退刀槽结构,及采用退刀槽底部浅表性的加工去除退刀槽表面的凹孔缺陷,消除应力集中,解决了凸轮轴退刀槽底部的淬火裂纹。     

船用凸轮轴的连续中频感应淬火

本文记述了我厂通过革新的感应器设计及工艺过程优化，成功地在国产数控机床和中频电源上实现了船用凸轮轴9个3组不同尺寸的凸轮的连续中频感应淬火生产，通过改进，产品质量的稳定性和高生产效率同时得到了兼顾。     

制动凸轮轴轴颈淬火感应器改进与应用

分析制动凸轮轴轴颈感应淬火特点,通过对原淬火感应器的改进,设计出新的分离型可移动式并联矩形感应器,提高了感应器的通用性及生产效率。     

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.     

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。     

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.     

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.     

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.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.