焊接经验公式在焊接工艺中的应用

本文对于手弧焊、埋弧焊、CO2气体保护焊等焊接方法的焊接电流、电弧电压经验公式进行了对比分析，指出了这些经验公式使用的范围及使用时须注意的问题。实践证明，这些公式简便、实用。     

熔模铸造生产中若干工艺的研究

介绍了熔模铸造工艺特点,压型型腔尺寸的计算方法。及旧模料回用处理和水玻璃预处理的机理与方法,指出在压型设计时,通过公式L=l(1+Δl)±(1/2～3/4)ΔM计算出来的尺寸数据是可靠的。     

晶体位错链长统计分布理论公式初探

本文在晶内位错链长在空间各向分布几率相等条件下,推导出经半无限区域归一化处理的单位体积内位错链长统计分布理论公式φ(l)dl=2ρl_λ~(-4)l~2 exp(-l~2/l_λ~2)dl金属纯Ni及1Cr18Ni9Ti的实验结果证实了该公式的正确性。     

电子封装微互连焊点力学行为的尺寸效应

研究了微互连模拟焊点在不同直径(d=200-575μm)和长度(l=75-525 μm)匹配条件下准静态微拉伸的力学行为.研究结果表明,焊点几何尺度因子d/l对焊点内的力学拘束及接头强度有重要影响;d/l增大时导致焊点中力学拘束和应力三轴度的提高,但接头强度并不完全符合Orowan近似公式的预测结果,保持l恒定而增加d时会出现强度变小的尺寸效应.研究结果还表明,无论无铅还是含铅钎料,其焊点拉伸强度与焊点体积(d2l)之间的变化关系符合反比例函数,即σF-Joint=1/Ad2l+B,焊点的强度随焊点体积的减小而显著增大,显示了焊点"越小越强"的"体积"尺寸效应.     

工业纯钛室温下的应变速率敏感性及Hollomon经验公式的改进

通过实验研究了工业纯钛TA2在室温下应变速率范围为1×10-4～1×10-2s-1的拉伸力学性能。发现TA2的拉伸力学性能存在显著的应变速率敏感性,随着应变速率的增加,材料的强度提高、塑性下降,应变速率敏感性指数较高。通过对Hollomon经验公式σ=Kεnεm的推导和TA2实验数据的分析发现应变速率敏感性指数m和应变硬化指数n分别会受到应变和应变速率的影响,并且它们之间均呈指数关系。因此对Hollomon经验公式提出了改进,得到了TA2在室温下改进的Hollomon模型。与传统的Hollomon经验公式及Johnson-Cook模型相比,改进的Hollomon模型的预测结果与实验结果更加吻合,能更准确地表现材料的拉伸力学性能。     

厚板滚弯回弹计算新方法

理论分析表明板材弯曲时后继变形中弹性变形所占比例较大,对于Q235而言,其比例达到了10％.新的回弹计算方法考虑了板材后继变形中弹性变形.将文献回弹公式、新的回弹公式与实际使用的经验公式和数值模拟进行对比,对比结果表明：新的回弹公式介于模拟结果与经验公式之间,更接近于经验公式,并且误差在10％以内,成形内半径越大,新旧方法之间的差距越大,新方法的优势越明显.     

双周经验公式应用于冷轧钢带的轧制力计算

应用双周经验公式计算了冷轧钢带的轧制力,6个实测例子的计算值平均相对误差为16．78％。应用双周经验公式可以简化采利科夫公式运算过程,有推广价值。     

STUDY OF LOADING CAPACITY OF MITRE WELDING JOINT

本文根据几种倾斜焊接接头单轴拉伸试验结果,提出了在复杂应力状态下焊接接头承载能力的新计算法,并推导出计算焊接接头强度的经验公式: σ_(eq)=((σ_w~2)+(ewτ_w~2)~(1/2)· 经验公式是根据塑性失稳和现代断裂力学为理论基础提出的。同时指出,倾斜焊接接头总是比垂直焊接接头有较高承载能力的传统概念及计算方法是不完整的。     

倾斜焊接接头承载能力的研究

本文根据几种倾斜焊接接头单轴拉伸试验结果,提出了在复杂应力状态下焊接接头承载能力的新计算法,并推导出计算焊接接头强度的经验公式: σ_(eq)=((σ_w~2) (ewτ_w~2)~(1/2)·经验公式是根据塑性失稳和现代断裂力学为理论基础提出的。同时指出,倾斜焊接接头总是比垂直焊接接头有较高承载能力的传统概念及计算方法是不完整的。     

基于FEM与经验公式的车削力预报系统研发

为实现切削力的快速预报,提出了一种结合有限元法与经验公式法来实现切削力预报的新方法。利用有限元分析软件AdvantEdge建立车削三维模型,并进行了车削力分析,采用经验公式构建车削力计算数学模型。以有限元值与经验公式值作为基础数据,利用Visual FoxPro开发车削力预报系统。为验证有限元法的准确性,进行了车削测力实验,通过在相同切削条件下的有限元值、经验公式值与实验值对比分析,结果证明采用有限元法来实现切削力的预报是可行的。     

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.     

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.     

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。     

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.