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关键词： 铝合金   激光焊接   气孔率   焊缝成形系数  

摘要： 分析铝合金激光焊接接头的性能,探究工艺参数对焊缝的宏观成型、微观组织以及力学性能的影响。以1060铝合金作为底板,选用直径为1.2 mm的5356铝合金作为焊丝,通过分别改变激光功率、送丝速度、激光扫描宽度3种工艺参数进行多组实验,对得出的不同焊缝分别进行宏观形貌分析、气孔分析、硬度测试和拉伸测试,并重点对焊缝的气孔和焊缝成形系数进行分析对比,根据不同的焊缝性能得到相对更优的实验参数,并通过控制变量法进行对比分析。最终实验结果表明,激光功率对焊缝的熔深影响较大,扫描宽度对焊缝的熔宽影响更大,因此激光功率和扫描宽度对焊缝成形系数的影响更大,而激光功率越大,送丝速度越快,焊缝中更容易形成气孔。

关键词： 长输管道   自动焊   熔铜   裂纹  

摘要： 熔铜裂纹是一种常见的焊接缺陷,长输管道环焊缝发生熔铜裂纹缺陷,不仅会造成裂纹处容易产生应力集中,降低接头强度性能,而且会加速管道环焊缝腐蚀进程。本文通过某天然气长输管道自动焊发生疑似环焊缝“熔铜”裂纹缺陷的具体典型案例进行深入研究分析,结合焊接施工现场情况和实验室结论综合判定缺陷性质,并分析缺陷产生直接和间接原因,并从管理措施和施工措施两个方面提出预防措施。

关键词： 失效   预紧力衰减   拉伸性能   螺栓连接   DIC分析  

摘要： 以CF/PEEK复合材料与铝合金螺栓连接结构为研究对象,分析静载条件下预紧力衰减对连接结构力学性能的影响,揭示接头的失效形式及失效机理,利用数字图像相关技术分析拉伸过程中的应变场变化。结果表明,随着预紧力的增加,连接结构的极限载荷呈现出先增大后减小的趋势,适当增加预紧力有助于提升极限载荷,而过高的预紧力则可能导致其下降。预紧力衰减使接头处的接触压力降低,导致极限载荷降低。CF/PEEK接头失效形式表现为纤维断裂、层间开裂及表层脱粘,而铝合金则表现为弯曲变形和挤压破坏。最大负应变的变化趋势与极限载荷对预紧力的依赖性相一致。预紧力的衰减不会改变应变分布特征,但会导致最大正应变和最大负应变的增加。

关键词： FPGA   Canny算法   自适应中值-高斯滤波   Sobel算子   Cordic算法  

摘要： 针对石油管道X射线环焊缝图像在复杂环境中实时性和准确率较低的问题,提出了一种基于FPGA的高效焊缝图像处理算法。该方法通过改进Canny算法并结合FPGA的并行处理特性,实现了快速准确的环焊缝图像边缘检测。通过引入自适应中值-高斯滤波器提升抗噪性能,采用Cordic算法优化Sobel算子的梯度幅值计算,并使用自适应阈值法解决了传统算法中阈值手动设置的局限性。研究实验结果表明,在100 MHz时钟频率下处理640×480分辨率的X射线焊缝缺陷图像仅需3.06 ms。与经过中值滤波改进的Canny算法相比,该算法在环焊缝缺陷边缘的连续性、细节保留和抗干扰能力方面显著提升,边缘点数、四连通域数、八连通域数分别提高了13.63%、37.43%和23.85%,满足复杂环境下高实时性管道焊缝缺陷图像处理的需求。

关键词： 安全阀   连接焊缝   焊缝开裂   电站锅炉  

摘要： 电站锅炉安全阀连接焊缝开裂是多因素耦合的结果。介绍电站锅炉安全阀连接焊缝开裂的表现,分析连接焊缝开裂的原因,主要包括焊接行为不规范、应力作用、材料组织劣化、环境介质腐蚀,并提出相应的修复方法,为电站锅炉安全阀的维护提供参考。

关键词： weld metal of high-strength steel   microstructure   strengthening and toughening   alloy element   process parameter  

摘要： High-strength steel, renowned for its optimal balance between strength and toughness as well as its exceptional weldability, has become a key structural material in critical applications such as long-distance oil and gas pipelines, offshore engineering structures, construction machinery, and hydropower facilities. The microstructure and mechanical properties of the weld metal-an integral component of the welded joint-directly impact the service safety and reliability of the entire welded structure in high-strength steel applications. Moreover, the solidification behavior and phase transformation processes of the weld metal play a pivotal role in determining its microstructure and mechanical properties. This study focuses on three crucial aspects: the synergistic effects of multi-component alloying, the design of welding process parameters, and the formulation of post-weld heat treatment regimes. It reviews recent advances in microstructure design and elucidates the strengthening and toughening mechanisms of weld metal in high-strength steel fusion welding. Furthermore, the correlation between strength and toughness inversion in weld metal is elucidated from the perspectives of chemical composition design and process parameters. Recent advancements and prospects in relevant fields are summarized, providing theoretical guidance for the development of welding materials and the preparation of weld metal in high-strength steels of 1000 MPa grade and above.

关键词： narrow gap welding   swing arc   rotating arc   cold wire   weld formation   microstructure  

摘要： Narrow gap gas metal arc welding (GMAW) is increasingly applied in the manufacturing of thick-walled structures, such as large ships, offshore equipment, and pressure pipelines. Previous research focused on the improving weld formation and welding efficiency in this process but seldom addressed the correlations among the welding process, joint microstructure, and mechanical properties. The study aims to modify the microstructure and properties of the joint while overcoming the limitations of groove gap on cold wire swaying amplitude in deep-groove welding, thereby enhancing the practicality of the process. A rotating/swing arc narrow gap metal active gas welding assisted by a cold wire with variable swaying amplitude is proposed. Effects of arc rotation frequency, cold wire feeding speed, and the horizontal oscillation cooperative rate between the cold wire and the swing arc (eta) on weld formation and welding efficiency are then investigated. Additionally, the evolution mechanisms of the microstructure and mechanical properties of cold wire-assisted rotating/swing arc narrow gap welding joints are clarified. Experimental results show that the cold wire-assisted rotating/swing arc processes yield stable weld formation and increase the welding efficiency by 25.7% and 44.2% at eta <= 0.5, respectively. Compared to the rotating arc process, the swing arc process achieves greater penetrations into the groove sidewalls and weld bottom even at smaller swaying amplitudes of the cold wire;the swing arc has no the reheating effect on the rear of the molten pool, thereby narrowing the coarse-grain heat-affected zone (CGHAZ). This nonreheating effect, combined with the heat absorption effect of the cold wire, accelerates the molten pool cooling, substantially refining the weld grain size and toughening the CGHAZ. Owing to the dominant factors of the microstructure type and grain size, impact energy near the fusion line increases by 53.8% while weld strength rises by 6.0%. Cons

关键词： 316H steel   weld metal   irradiation   He bubble   phase field simulation  

摘要： 316H steel is an important structural material candidate for Generation-IV advanced nuclear reactors. During service, the material operates under conditions of high temperature, irradiation, and complex stress for extended durations, and the working environment is extremely harsh. In particular, He bubbles, generated through nuclear transmutation under irradiation, can cause severe irradiation em-brittlement and accelerate the failure of the material. To clarify the role of He bubbles in the degradation of 316H steel and weld metal, this study proposes a coupled computational framework that integrates the phase field model and crystal plasticity. Within this framework, the nucleation, growth, and coalescence of He bubbles in 316H steel and weld metal were simulated, and their mechanical responses were system-atically analyzed. The research shows that He bubbles nucleate and grow by absorbing supersaturated vacancies and He atoms. In the later stage, they grow through coalescence and Ostwald ripening pro-cesses. As the He bubble size increases, the internal pressure gradually decreases until reaching an equilibrium state. The high density of dislocations in the weld metal, which preferentially absorb interstitial atoms, results in an increased vacancy concentration. Meanwhile, dislocations act as rapid diffusion chan-nels. These two factors together contribute to the rapid growth of He bubbles. An increase in diffusion ca-pacity does not change the final proportion of He bubbles;instead, it accelerates the nucleation and growth processes, thereby promoting the kinetic evolution of He bubbles in the weld metal. At small strains, the stress-strain response is governed by the effects of external strain and the internal pressure of He bubbles, with the macroscopic stress value being negative. As the external strain increases, the stress-strain response becomes influenced by the external strain. During tensile deformation, significant stress concentration arises at the He

关键词： 深度学习   飞行时间衍射法   焊缝缺陷检测   跨窗口自注意力机制  

摘要： 针对收集焊缝缺陷的飞行时间衍射法（TOFD）图像中存在高噪声、前背景对比度低及多尺度缺陷共存等问题，本文提出一种高效的TOFD焊缝缺陷识别模型。首先在特征提取阶段引入深度可分离卷积（DW），在降低计算开销的同时保持模型表达能力；其次设计了新颖的Efficient Vision Transformer(EVT)模块，结合改进的跨窗口自注意力机制（SWMSA）与优化的梯度路径，显著提升注意力表达能力且有效减少了冗余计算；最后构建了具有代表性的TOFD焊缝缺陷数据集，用于验证模型性能。实验结果表明，该模型在缺陷识别上取得98.8%的高准确率，同时保持了较低的参数量（7.56×10～6）、浮点运算数（4.27×10～9）和推理时间（27.6 ms），并在多项关键指标上均超越了现有的经典网络，具有较高的工业部署应用潜力。

关键词： 公路工程   工程计量   伸缩缝   桩基   波形护栏   定额组价  

摘要： 在公路工程计量实操中存在较多争议问题，施工方与监理、审计方在对争议内容的理解不同而产生计量与审减的不同结果。文章作者根据实际工作中遇到的部分争议问题，依据不同项目的计量和审减结果，着重对“伸缩缝凿除混凝土”“地系梁与桩基交接部分的工程量”“波形护栏钢板的附属工作内容”的计量与审减问题进行论述，意在阐明不同单位对争议问题的理解及原因，为同类工程提供参考。