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随着航运市场对大吨位船舶需求的增大以及国际公约对新建船舶PSPC的严格要求,为了提高船舶建造效率与舱室密性质量,越来越多的国际一流造船企业纷纷在分段建造过程中采用角焊缝充气的工艺实施密性检验。介绍了角焊缝密性试验原理,分析了角焊缝密性试验的优点,指出了角焊缝密性试验弊端,同时提出了改进方法。 相似文献
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介绍320000t VLCC船体分段制作时,利用充气密性试验方法对分段结构中水密舱壁、角焊缝及水密堵板进行密性试验的原理及方法,给出了船体分段制作过程的装配顺序、工艺要求及焊接要求. 相似文献
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海洋平台钢结构壁厚50mm以上的中厚板焊缝,按照规范要求需要进行焊后热处理(PWHT)。这些构件通常为平台的主要构件或特殊构件,焊缝质量直接影响到平台的安全。当前随着海洋平台设计规模的日益增大,建造过程中需要进行焊后热处理(PWHT)的焊缝越来越多,暴露的问题也日益多样性。本文结合工程实际,详细总结海洋平台钢结构在焊后热处理(PWHT)过程中常出现的但不易被发现的一些隐患问题,以期通过介绍,达到相互交流和借鉴的目的。 相似文献
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分段密性试验方法在船舶建造中的应用 总被引:1,自引:1,他引:0
密性试验是有效检验焊接质量的方法,文章分析了传统密性试验方法和分段密性试验方法的优缺点,从满足PSPC标准、缩短造船周期以及可制造性等方面综合考虑,提出了不同建造阶段、不同焊缝形式推行分段密性试验的方法. 相似文献
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CO_2气体保护焊早在六十年代已在我国机械制造和汽车制造行业中应用。我厂是在八十年代初期才在船体车间进行试验,不久在万吨轮的建造中用于双层底分段角焊缝的焊接,在国内造船系统中也算是个应用较早的厂家之一。 在试应用中由于高的生产效率和小的焊接变形加深了人们对这种焊接方法的认识,同时也改变了“CO_2气体保护焊 相似文献
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通过对TA2钛合金焊接特点的分析,优选合理的焊接工艺、气体保护方式和焊接规范进行试验,试验数据证明采用TIG焊焊接TA2钛合金钢不仅焊缝成型好,微观组织及力学性能也达到了相关标准要求.文章还给出了钛及钛合金的焊接保护焊接区域免受空气侵蚀的相关观点. 相似文献
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In support of the development of improved fillet weld sizing criteria for lightweight shipboard structures, a comprehensive static strength test program using longitudinal and transverse shear specimens according to AWS B4.0 Standards has been conducted. This test program covers base material with strength ranging from 71 ksi (490 MPa) to 96 ksi (660 MPa) and weld size ranging from 1/8″ (3 mm) to 3/8″ (10 mm). This paper focuses on a traction stress based analysis of the test data as an effort to establish a unified shear strength definition for load-carrying fillet weld specimens regardless of shear loading conditions. The proposed shear strength definition proves to be effective in correlating the fillet weld strength test data of the longitudinal and transverse shear specimens. The results of this investigation demonstrate that existing shear strength definitions used by various weld sizing criteria such as those given by Class Societies have two major limitations: (1) it cannot be related to a critical stress state on experimentally observed failure plane in transverse shear specimens; (2) it underestimates shear stress at failure due to severe stress concentration at weld end in typical longitudinal shear specimens. These two limitations have been shown to be the major cause for having two significantly different shear strength values: one is transverse shear strength obtained from transverse shear specimens and the other is longitudinal shear strength obtained from longitudinal shear specimens. 相似文献
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选取典型对接结构和角接结构进行焊接试验,并进行热弹塑性仿真计算,研究测点的焊接温度和残余变形规律.结果表明,测点经历了加热-峰值-冷却过程.对接结构的焊接角变形较小,横向收缩变形较大;角接结构的焊接角变形相对较大,横向收缩变形相对较小. 相似文献
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沟槽面减阻效果影响因素及减阻机理的分析 总被引:1,自引:0,他引:1
采用雷诺平均N-S方程和RNG k-ε湍流模型计算V型沟槽面的湍流边界层流动和粘性阻力,研究了沟槽尖峰形状和雷诺数对减阻效果的影响规律,初步分析了沟槽面减阻机理.指出:沟槽尖峰处的圆角半径越小其减阻效果越好,沟槽斜面中下部的壁面应力随着圆角半径的减小而降低,但尖峰处的局部壁面应力会随之增大;来流速度对沟槽减阻率的影响很大,对于一种尺度的V型沟槽,存在着一个具有较好减阻效果的来流速度范围,而沟槽面在沿来流方向上的布置位置对减阻效果的影响非常小;沟槽尺度对减阻效果很剧烈;沟槽尖峰处生成的二次涡是产生减阻效果的根本原因,二次涡的强弱与沟槽减阻率的大小紧密相关. 相似文献
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The paper presents the results of metal inert gas T-joint fillet welding tests of small scale rectangular stiffened steel plates longer than the standard test specimen. In the literature the focus is typically on plates with a small aspect ratio and the present work deals with plates of higher aspect ratio, which are the typical ones in marine structures, aiming to determine if there is any significant effect of welding along the longitudinal direction. Nonlinear thermo-elasto-plastic finite element models are adopted to evaluate the temperature distribution, welding induced distortions and residual stress in the stiffened plates of shipbuilding steel. Given the difficulty in data acquisition of temperature-dependent properties of the material, a simplified model of the properties is proposed, based on the values at room temperature. Good agreement is observed between the measured and simulated temperatures, indicating that the current finite element approach is appropriate to simulate the welding process. The proposed simplified material model can be efficiently used in the finite element analysis of welded steel structures. It is concluded that the welding parameters have more significant influence on the structural responses than the dimension of the plate. 相似文献
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激光电弧复合焊克服了传统电弧焊和激光焊的缺点,其良好的焊接特性及可控的焊接成本,使其完全满足邮轮上层建筑建造的技术要求,即:焊后上层建筑外板平整、线型流畅和焊缝成形美观等,且焊接成本应在可控范围。由于目前船级社规范以及国内相关标准尚未制定出可执行的激光电弧复合焊焊接工艺认可的技术要求,制约了激光电弧复合焊在我国邮轮建造领域的应用。为了获得科学合理的激光电弧复合焊焊接工艺认可的工艺技术参数,通过焊接工艺试验,就激光电弧复合焊的特性、焊接设备的选配、试验所用的钢板和焊接材料进行了详细介绍;经对焊接工艺试验数据的分析研究,获得并建立了激光电弧复合焊焊接工艺认可所需的最佳可控的焊接工艺技术参数。这些工艺技术参数不仅能帮助船厂顺利完成激光电弧复合焊焊接工艺计划书等焊接工艺文件的编制、焊接工艺试验的实施及其认可,也能为完善规范提供参考,同时还为激光电弧复合焊在我国建造的邮轮上得以顺利实施提供技术支持。 相似文献