316L／20G爆炸焊接复合界面的研究

用电子显微分析方法研究了３１６Ｌ／２０Ｇ爆炸焊接复合界面。结果表明，复合界面为带有的旋涡的准正弦波形，复合方式为直接复合和熔化复合二种。２０Ｇ侧有一随正弦波形变化的过渡层，其宽度在０．０７ｍｍ范围内。去应力退火后析出了硬脆的ＦｅＣｒ型σ相，造成复合板性能下降。     

矿用圆环链25SiMnMoV钢金相组织研究与分析

本文研究了25SiMnMoV钢在不同奥氏体优化温度、加热速度及冷却速度下组织变化规律.并分析了D级矿用圆环链焊接接头组织.可为矿用圆环链焊接、热处理生产提供组织转变理论依据。     

电弧焊阴极区空间电场形成动画显示系统研究

介绍了所研究的显示系统的原理及软件情况．利用本软件可使教材有关内容更加生动形象，提高教学水平．     

Effect of high anodic polarization on the passive layer properties of superduplex stainless steel friction stir welds at different chloride electrolyte pH values and temperatures

The conditions used for friction stir welding of duplex stainless steels determine the resulting mechanical and corrosion performance of the material.This study investigates the corrosion resistance of UNS S32750 and S32760 superduplex stainless steels(SDSSs)joined by friction stir welding,employing cyclic polarization,Mott–Schottky,and microscopy techniques for analysis.The microscopy images indicated the presence of a deleterious intermetallic phase after electrolytic etching of S32760,as well as decreased corrosion resistance.The presence of molybdenum in the steels promoted better passive behavior at low pH.The Mott–Schottky curves revealed p-n heterojunction behavior of the passive oxide.Images acquired after the polarization test by scanning electron microscopy showed higher passivation propensity with increases of temperature and pH.     

先进高强钢DP590焊缝的组织特征和力学性能改善

The effects of the welding current mode in resistance spot welding on the microstructure and mechanical properties of advanced high-strength steel dual-phase 590 (DP590) sheets were investigated. Results showed that a rough martensitic structure was formed in the weld zone of the sample welded via the single-pulsed mode, whereas the microstructure in the heat-affected zone consisted of a very rough martensitic microstructure and rough ferrite. However, using the secondary pulse mode led to the formation of tempered martensite in the weld zone. The maximum load and the energy absorption to failure of the samples with the secondary pulsed cycle were higher than those of the samples with the single-pulsed mode. Tensile shear results indicated that the secondary pulsed mode could significantly change the mode of failure upon shear tension testing. Therefore, the obtained results suggest that the use of secondary pulsed mode can improve the microstructural feature and mechanical properties of advanced high-strength steel DP590 welds.     

Interface microstructure and formation mechanism of ultrasonic spot welding for Al–Ti dissimilar metals

The present study focuses on interface microstructure and joint formation. AA6061 aluminum alloy (Al) and commercial pure ti-tanium (Ti) joints were welded by ultrasonic spot welding (USW). The welding energy was 1100–3200 J. The Al–Ti joint appearance and in-terface microstructure were observed mainly via optical microscopy and field emission scanning electron microscopy. Results indicated that a good joint can be achieved only with proper welding energy of 2150 J. No significant intermetallic compound (IMC) was found under all con-ditions. The high energy barriers of Al–Ti and difficulties in diffusion were the main reasons for the absence of IMC according to kinetic ana-lysis. The heat input is crucial for the material plastic flow and bonding area, which plays an important role in the joint formation.     

焊接速度对自适应双轴肩搅拌摩擦焊接Al–Mg合金接头微观组织和机械性能的影响

The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this study. The microstructure was studied using optical microscopy and electron backscatter diffraction (EBSD). Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical properties. Sound joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed increased. The EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization behavior. Specific attention was given to the relationship between the local microstructure and mechanical properties. Microhardness measurements show that the average hardness of the stir zone (SZ) was greater than that of the base material, which was only affected slightly by the travel speed. The tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.     

基于滑模与状态反馈模糊加权控制的气动伺服焊枪柔性接触研究

在焊枪电极接近运动过程中,期望接近速度大且在接触面附近快速降速以减小接触时的冲击力,实现一种柔性接触,对于提高焊接的效率和质量具有很重要的作用.滑模控制虽然能有效降低焊枪电极接触力,但所用时间较长.本文将基于模糊逻辑的滑模与状态反馈加权控制运用到气动伺服焊枪系统中,在建立系统模型的基础上设计滑模切换函数和滑模控制律,通过极点配置的方法设计状态反馈控制器,之后基于模糊控制设计滑模与状态反馈模糊加权控制器,最后通过实验验证提出的控制策略.实验结果表明设计的控制器控制效果优于最大量控制和滑模控制,可有效实现柔性接触.     

深冷处理对5A06铝合金FSW接头组织和力学性能的影响

为了避免铝合金焊接接头软化,提升接头力学性能,采用FSW对5A06铝合金进行对接试验,在转速为1 200 r/min、焊速为150 mm/min的条件下,将焊接接头加工成一定尺寸的金相试样和拉伸试样,研究深冷处理时间对5A06铝合金搅拌摩擦焊接头组织和力学性能的影响规律,采用显微组织观察试验、显微硬度试验和拉伸试验等方法,对接头组织和力学性能进行表征与分析。结果表明：深冷处理具有细化晶粒、促进析出相析出的作用,提高了接头力学性能;经过12 h深冷处理后,接头的抗拉强度和伸长率分别达到385.3 MPa和17.2%,与未经深冷处理的接头相比,分别提高了7.4%和23.7%。因此,深冷处理可以有效提升铝合金焊接接头的力学性能,为其更广泛的应用提供了理论基础和技术参考。     

全位置自动焊机驱动电机控制的研究

着重讨论一种利用脉宽调制线路来实现电机速度控制的方法 ,该方法保证了全位置自动焊机在工作时行走速度的恒定。