Study on Reduction of Residual Stress of Welding Joint Using Vibration

利用振动降低焊接接头残余应力的研究

基本信息

批准号：
05650250
负责人：
AOKI Shigeru
金额：
$ 1.47万
依托单位：
Tokyo Metropolitan College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

Welding is widely used for construction of many structures. There exists residual stress near the bead because of locally given heat. Tensile residual stress on the surface degrades strength for cumulative damage. Some reduction methods of residual stress were presented. In this paper, a new method is proposed in which vibrational load is used during welding operation and an analytical method for the proposed method is presented. Advantage of this method is that vibrational load is generated by a small shaker. This method is expected to be a practical one.First, reduction of residual stress is examined experimentally. Two plates of 100mm width are used. Two plates of rolled steel for general use (JIS SS400) are supported on the supporting devices by bolts and shaken by a small shaker during welding. Specimens are butt welded using automatic CO_2 gas shielded arc welding machine. Groove is V-shaped. Welding is completed through one pass. Excitation frequency is chosen as 60Hz which is t … More he fundamantal natural frequency of specimens before welding. In order to examine reduction effect of residual stress at non-resonane frequency, excitation frequency is also chosen as 100Hz. Residual stress is measured by removing the quenched scale chemically and using a parelelled beam X-ray diffractometer with a scintillation counter.From the experiment, it is found that on the bead, tensile residual stress is significantly reduced when vibrational load is acting during welding. At points near the bead, residual stress is also reduced. At points far from the bead, compressive residual stress tends to be tensile. Residual stress decreases as the amplitude of excitation increases.Next, an analytical method for reduction of residual stress by the proposed method is examined. It is obvious that reduction of residual stress is caused by local plastic deformation because initial residual stress is great and nearly equal to yielding stress. Thus, an analytical model which consists of mass and preloaded spring with elasto-plastic characteristic is used. From the analysis, it is found that reduction rate of residual stress increases as the amplitude of excitation increases. Thus, effectiveness of the proposed method can be demonstraited by experimnet and analysis. Less

焊接广泛用于构建许多结构。由于局部给予热量，珠子附近存在残留应力。表面上的拉伸残留应力会降低强度，以累积损伤。提出了一些残留应力的减少方法。在本文中，提出了一种新方法，其中在焊接操作过程中使用振动负载，并提出了提出方法的分析方法。这种方法的优点是振动载荷是由小型振动器产生的。预计这种方法将是一种实用方法。首先，通过实验检查残余应力的减少。使用了两个100mm宽度的板。螺栓支撑在支撑设备上，在支撑设备上支撑了两块滚动钢板（JIS SS400），并在焊接过程中被小型振动器摇动。使用自动CO_2气体屏蔽电弧焊接机对标本进行焊接。凹槽是V形。焊接是通过一次通行证完成的。兴奋频率被选为60Hz，它是……焊接之前的较高的标本的财务固有频率。为了检查在非谐音频率下残留应力的减少效应，还选择了兴奋频率为100Hz。残余应力是通过化学去除淬火刻度和使用闪烁计数器的式X射线衍射仪来测量的。在珠子附近的点，残留应力也减轻。在远离珠子的点，压缩残留应力往往是拉伸的。随着兴奋的放大器的增加，残余应力减少。隔离，检查了通过提出的方法减少残余应力的一种分析方法。显然，残留应力的减少是由局部塑性变形引起的，因为初始残留应力很大，几乎等于产生应力。这是使用由质量和带有弹性塑料特征的质量弹簧组成的分析模型。从分析中可以发现，随着兴奋的放大器的增加，残余应力的降低率会增加。可以通过实验网和分析来证明所提出方法的有效性。较少的