共查询到20条相似文献,搜索用时 110 毫秒
1.
2.
3.
为认识超窄间隙焊接母材熔化特性及熔池形成机制,在放置焊剂带的I形坡口中进行熔化极电弧焊接试验,采用一种快速中断电弧的方法,保留焊接过程中焊剂带、坡口底部和侧壁的熔化形态.结果表明,电弧区焊剂带热收缩效应和固壁约束作用能有效约束坡口中电弧作用范围.当选择合适的侧壁根部焊剂带裸露高度时,电弧加热区域控制在坡口底部和侧壁根部,熔滴过渡的冲击作用及电弧力集中在熔池前端,使熔融金属产生有利于排出熔池中气体和熔渣的流动,形成无缺陷焊缝.当侧壁根部焊剂带裸露高度大于一定值时,电弧所受约束减小,加热区域扩展到较大范围的坡口侧壁上,熔滴过渡分散在坡口底部和侧壁,熔融金属难以形成贯穿熔池的流动,焊缝存在较多孔洞. 相似文献
4.
5.
6.
本文通过研究厚壁管窄间隙焊接侧壁熔透技术,开发厚壁大径管窄间隙TIG组合坡口,设计焊接该种坡口厚壁管的特定范围焊接工艺参数,解决了厚壁大径管窄间隙焊的工艺难点,取得了良好的生产效果。 相似文献
7.
采用坡口侧壁放置绝缘片的方式约束电弧,在4 mm宽的I型坡口内进行窄间隙TIG焊接试验,通过分析坡口截面各区域熔化面积及其所占比例的变化,研究绝缘片约束TIG电弧的加热特性.结果表明,窄间隙中依靠绝缘片对弧根的固壁约束作用能够将电弧加热区域限制在坡口底部,增强电弧对坡口底部和底角的加热效果,防止电弧集中于侧壁燃烧;弧长、绝缘片对弧根的约束程度和焊接电流三者匹配时,可使坡口底角获得可靠熔合;弧长过长会导致电弧直接向侧壁攀升,且无法依靠绝缘片将电弧控制在坡口底部;绝缘片对弧根约束过多以及采用较大的焊接电流,均会导致电弧将绝缘片熔化,造成电弧燃烧不稳定. 相似文献
8.
《热加工工艺》2017,(13)
侧壁未熔合是铝合金厚板窄间隙焊接过程中很容易出现的焊接缺陷。通过采用电机驱动弯曲导电嘴摆动来控制电弧的偏转,解决了侧壁熔合不良的问题。通过正交试验法以及单因素变量法,研究了不同焊接工艺参数对6061-T6铝合金板侧壁熔深的影响规律。结果表明,摆动角度是影响侧壁熔深的主要因素,其次是焊接速度和侧壁停留时间。对于坡口底部宽度10 mm、顶部宽度13 mm的U型坡口,最优的焊接工艺参数为摆动角度50°、侧壁停留时间0.5 s、摆动速度350°/s、送丝速度11 m/min、焊接速度200 mm/min。以最优的工艺参数为参考,实现了40 mm厚6061-T6铝合金厚板的单道多层窄间隙焊接,获得了侧壁熔合良好的焊接接头。热处理后的接头平均抗拉强度达到246.7 MPa。 相似文献
9.
10.
11.
采用非接触电涡流传感器应用于焊缝跟踪,利用指数运算电路补偿传感器的线性度,从而加大了传感器的量程,消除了传感器在焊缝跟踪过程中的失真情况.选用摆动式涡流传感器检测焊缝偏差信息,实现复杂形状焊缝的平板对接I形坡口的自动跟踪.应用区域积分差值加权比较法对焊缝的偏差信息进行分析,消除了因板厚不均匀以及错位的误判,在采样数据点不变的情况下,提高了焊缝跟踪精度.结果表明,摆动式涡流传感器用于焊缝自动跟踪可行,跟踪效果好,为目前对自动焊缝跟踪技术的研究提供了一种新的方法. 相似文献
12.
13.
研制了一套用于水下高压局部干式自动焊接试验控制系统。此试验系统采用液压作为动力源,可在由排水罩形成的局部干式空间内进行MIG焊接。此系统采用西门子PLC、压力传感器、行程开关、水下摆心传感器等作为其主要的控制部件。由焊接环境控制、液压驱动自动焊机控制和水下摄像三套子系统构成。此系统可以实现在高压有水环境下远程遥控的局部干式自动焊接。结果表明,此焊接试验装置工作稳定,水下焊接焊缝质量良好。这些研究工作为核电厂水下焊接维修奠定基础。 相似文献
14.
A nano probe system which can measure precise micro parts or optical parts in nanometer range resolution and scratch contact force in mN scale was demonstrated. The nano probe was originally designed for on-machine measuring applications and one kind of contact type measuring probes was designed for miniaturized or microfactory system. It ideally should be of small size and able to measure surface topography in nanometer scale. A commercial capacitive displacement sensor was proposed. It was a new concept in nano probe systems which can measure the displacement of shaft driven by the variation of surface topography. The nano probe mainly consisted of three parts: a capacitive displacement sensor, a porous type air slide and a contact probe part with various tip radiuses. The porous type air slide assured the shaft slided smoothly with controllable normal force in mN scale and had high positioning accuracy. The probe part which was directly in contact with target surface, can be applied to micro/nanoscale scratching as well as the measurement of sample topography by a simple tip change. 相似文献
15.
Xie Zexiao Wang Jianguo Zhang Qiumei 《International Journal of Machine Tools and Manufacture》2005,45(12-13):1474-1486
To meet the demand of measuring the complex prototypes completely in reverse engineering, a multi-probe measurement system integrated with a coordinate measuring machine (CMM), a structured-light sensor, a trigger probe and a rotary table is presented in this paper. The structured-light sensor is designed with optimal structure, and its model is established based on the CMM to simplify its parameters, this enables the sensor to be calibrated expediently at any condition. Three measuring modes are proposed considering the efficiency of the structured-light sensor, the high accuracy and flexibility of the trigger probe and the rotation of the table for finding proper scanning views. The structured-light sensor is usually applied to scan the profile of a part from different views, while the trigger probe is used to measure the edge and key features of the part. The data generated by different modes can be merged into a whole data body. The system possesses the function of obtaining the coordinate of nearly any point on a complicated part. Experiment studies on the accuracy of the structured-light sensor, data patch assembling and data merging show that the total accuracy of the system is ±0.033 mm. 相似文献
16.
在弯曲模具成形板料的载荷测试中,普通传感器因信噪比不高、测试空间狭小而可能产生功能失效。根据金属在塑性成形时的应力分布规律,设计了一种压电式探针测力传感器,当探针的一端受到板料弯曲变形对其的挤压作用时,产生的应力沿探针轴向传播,通过测量探针所受载荷,可得到整板的弯曲成形力。为了检验压电式探针测力传感器的性能,特别设计了一副弯曲组合模具,并将压电式探针测力传感器倾斜安装在模具型腔中,测试板料在弯曲成形中所受载荷,经反复试验,并将测试结果与经验公式计算结果进行比对,测试偏差在可接受范围内,结果证明传感器性能是稳定可靠的。 相似文献
17.
根据海底沉积物原位测量同步采样系统在海底原位测量过程中的工作要求设计温度探杆,搭建与测试该系统的温度测量单元。温度测量单元采集STM32F407主控板采集的温度传感器数据。以DHX-010恒温水槽为标准,对NTC10K型传感器、温度探杆和Pt100型传感器进行了静态与动态测量。测得NTC10K的最大稳态误差为0.71℃,温度探杆的最大稳态误差为0.62℃,Pt100型传感器的最大稳态误差为0.8℃;测得NTC10K型传感器、温度探杆和Pt100型传感器从室温阶跃变化到15℃时的动态响应时间。研究结论为海底原位观测系统的温度测量和运动控制提供了参考。 相似文献
18.
A prototype of an embedded corrosion sensor has been developed for assessing the corrosion status of reinforcing steel bar (rebar) in concrete. The integrated sensor unit includes an Ag/AgCl probe, a metallic oxide probe, a multi‐electrode array sensor (MAS), and a four‐pin (Wenner) array stainless steel electrode for chloride content, pH, microcell corrosion current, and localized concrete resistivity measurements, respectively. A stable solid probe was used as the reference probe in this unit to express the potentiometric measurement of chloride content and pH probes. In this study, the chloride and pH probes were calibrated in simulated pore solutions (SPSs) regarding temperature and pH fluctuations. The corrosion current results of the MAS probe in SPSs matched very well with those obtained by the linear polarization resistance technique, which was conducted on companion carbon steel specimens. A sensor prototype was embedded into a paste cylinder for long‐term performance evaluation. Up‐to‐date results show that the sensor probes exhibit excellent sensitivity and reliability through 1 year of monitoring. Continuous monitoring in the laboratory for extended periods is underway. 相似文献
19.
飞机多层结构铆钉周围埋藏裂纹检测是无损检测领域的一个难点和热点,脉冲涡流能够对这种裂纹进行有效的检测。针对这种缺陷检测,本研究采用了一种双激励线圈且用隧道磁电阻(TMR)为接收的新型探头。双激励源反向联接,激励电流不至于过大,但磁场却能达到局部聚焦的作用。通过大量试验对该传感器参数进行优化选择,以提高传感器的检测灵敏度。试验结果表明:当激励线圈绕制180匝、两激励线圈间距为20~30 mm、单个线圈水平夹角为60°~90°、且TMR位于裂纹正上方时探头的检测灵敏度最大。该研究结果可为飞机多层结构铆钉周围裂纹脉冲涡流检测探头设计提供参考。 相似文献