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对海底管道焊接和ECA评估技术作了简介,对荔湾3-1项目采用GMAW和SAW两种焊接工艺完成的海底管线环焊缝的表面缺陷和内部缺陷的临界尺寸进行了评估。评估结果给出了海底管线对接环焊缝的缺陷接收标准,该标准超出常规标准中的缺陷验收范围,能够降低海管焊接返修率,缩短施工周期,降低成本。 相似文献
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对海底管道焊接和ECA评估技术作了简介,对荔湾3—1项目采用GMAW和SAW两种焊接工艺完成的海底管线环焊缝的表面缺陷和内部缺陷的临界尺寸进行了评估。评估结果给出了海底管线对接环焊缝的缺陷接收标准,该标准超出常规标准中的缺陷验收范围,能够降低海管焊接返修率,缩短施工周期,降低成本。 相似文献
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1问题的提出2007年6月,笔者应邀对西气东输管线与陕京管道二线的安平-泰安站管线进行了验证性X射线检测。该管线钢管为1 016 mm×14.9 mm,输送介质为天然气,输送压力为10 MPa。此段管线在之前做管道漏磁腐蚀检测时,发现有6处焊缝存在漏磁现象。为此,委托单位要求在不停止输送天然气、不降低输送压力、不破坏管线防腐层(焊口两端各150 mm为橡胶热收缩套,厚度约9 mm)的条件下,对6处焊缝缺陷做验证性X射线检测,以进一步确定缺陷性质和大小。该检测任务的难点为①需克服防腐层的影响。②需要克服高速流动且极为密集的天然气气体的影响。2检测工艺试验2.1模拟焊缝的制作用相同材质和规格的管子,采用相同焊接工艺焊接模拟焊缝。做出咬边、内凹等人工缺陷,咬边深约0.5 mm,长30 mm;内凹深约1 mm,长30 mm(图1)。图1钢管模拟焊缝及人工缺陷2.2防腐层对模拟焊缝检测的影响试验模拟焊缝完成后,用XXQ3005射线探伤机进行双壁单影射线检测。焦距1 200 mm,管电压290 kV,曝光时间12 min。由此曝光工艺所获得的底片质量良好,灵敏度和黑度符合要求。在焊缝两边作喷砂处理后,用与管线相同的橡胶... 相似文献
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通过设计制作相关试块,开发PAUT检验工艺,实现对316不锈钢1英寸小径管工艺管线焊缝的检验。结果表明,相控阵检测结果与射线结果相对应,无漏检情况发生,且检测精度较高。该成果可对今后同类工艺管线焊缝的检验提供技术支持。 相似文献
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华能玉环电厂超超临界机组二期工程,锅炉水冷壁鳍片小径厚壁管安装前的检验中,发现大量锅炉对接自动焊焊缝存在较严重的未熔合缺陷,通过分析缺陷产生的原因及性质,采用射线与超声波相结合的无损检测方法,可显著提高缺陷的检出率。 相似文献
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介绍了百万千瓦级蒸汽发生器管板堆焊层缺陷形成的原因,针对某制造厂发生的管板堆焊层的质量问题,采用分析和试验的方法确定该缺陷对后续管子管板封口焊缝质量的影响,并提出了该质量问题的处理方案,为处理和提高管板镍基堆焊层的质量问题提供参考。 相似文献
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含裂纹缺陷的环焊缝失效分析,是解决X70及以上高钢级管道环焊缝质量风险的必要环节。文中对现阶段含裂纹缺陷的环焊缝排查和失效分析进行了梳理和成果总结分析,及时发现问题和规律,为后续安全管控和裂纹机理研究提供参考。已有失效分析规律总结如下:X70及X80管道环焊缝裂纹以根焊开裂形式为主;变壁厚、管道顶部和底部等位置容易发生环焊缝裂纹缺陷,焊接施工和缺陷无损检测及评判时应重点关注,尽量避免漏评误判;焊瘤、错边、余高等外观检测指标超标,导致环焊缝成形较差,影响裂纹缺陷的检出并加重根焊位置的应力集中。基于上述规律,建议对新建管道需加强针对管道环焊缝外观检测、根焊裂纹检测工艺。而对于在役管道,重点防范弯曲等附加载荷影响,依托环焊缝裂纹失效分析,进一步研究环焊缝裂纹形成的微观机理和控制参数。 相似文献
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针对单车车架焊缝检测效率低、成本高、检测过程复杂等问题, 提出一种基于弱磁检测技术的共享单车车架焊缝内部缺陷检测方法。通过高精度的TMR测磁传感器采集工件不同位置的微弱磁磁信号, 并对信号进行平滑处理。由于工件焊缝缺陷处的磁导率与无缺陷处的磁导率存在差异, 折射后被地磁场磁化后的磁场强度不同, 从而判断焊缝内是否存在缺陷。与常规磁法检测不同, 本检测方法无需对工件进行磁化, 无需耦合剂, 可实现非接触、在役检测, 为共享单车焊缝的快速、高效检测提供新的思路与方法。 相似文献
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Summary This paper describes an investigation of the very low cycle fatigue strength of HT570 steel welded joints containing weld defects to determine the acceptable size of weld defects in girth welds of underground gas pipelines subjected to cyclic ground displacements due to earthquakes. Butt welded joints containing incomplete penetration (IP), blowholes (BH), lack of fusion in theintermedi‐ate pass (LF), and cracks in the penetration bead (CR) were prepared and tested under strain‐controlled conditions. All specimens tested in the present research study satisfy the fatigue design curve for girth welds of underground gas pipelines. The fatigue strength of specimens containing weld defects generally decreases with an increasing equivalent defect size. The shape of a crack initiated from a defect is affected by the reinforcement, with the surface crack propagating rapidly along the weld toe of the penetration weld over the width of the specimen. The relationship between the J‐integral range and the crack propagation rate under a very low cycle fatigue load is virtually the same as the extension of the relationship in the low J‐integral range. A crack propagation analysis based on the defect being regarded as a crack is performed to determine the relationship between the defect size and the number of cycles over the plate thickness. The critical size of defects in welds of gas pipelines under cyclic ground displacements is proposed by the analysis. The critical crack size of surface defects is applicable to buried defects, because surface defects give a more conservative evaluation than buried defects. The analytical results provide more conservative estimations than the experimental ones. 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):731-736
AbstractSpot welds are used extensively by automobile manufacturers as an efficient method for joining sheet steel. The quality of them can be tested non-destructively by using ultrasound. But when spot weld defect happens, the current ultrasonic inspection methods of weld quality are difficult to achieve an ideal result especially for the stick weld defect which is one of the most important types of spot weld defects in the automotive body. At first, this paper detailedly analyses the echo characteristics of ultrasonic curves which can reflect different spot welding joint defects. After echo characteristics qualitative analysis of different spot weld defects, a peak value marking algorithm is developed to identify the joint defects especially the stick weld defect rapidly and efficiently through selecting and confirming many optimal characteristic parameters. Finally, a lot of experiments are performed to verify the proposed methods. The results indicate that this fast identification method is credible and the identification rate can reach 95% in total test samples. 相似文献
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高强度钢焊接裂纹检测及其成因分析 总被引:1,自引:0,他引:1
为了充分认识高屈强比、高强度低温材料焊接裂纹的敏感性,通过对NK—HIT—EN610U2L低合金高强度钢球罐支柱角焊缝裂纹的检测、解剖对比和成因分析,发现焊缝外表面缺陷与内部焊接缺陷存在一定关系,高应力设计部位比较突出,因此检测与焊接要引起高度注意。 相似文献
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Monitoring corrosion defects in pipelines by non-destructive inspection In order to be able to detect defects such as dents, corrosion, cracks, etc. in time, pipelines are inspected at regular intervals. So-called intelligent pigs working on the basis of non-destructive technologies have proved successful for pipeline inspection. In the field of corrosion detection, the ultrasonic technology provides precise and detailed wall thickness measurement. Based on the determined corrosion profile, suitable assessment methods can be used to calculate the remaining safe pipeline pressure (MAOP) for the corroded pipeline. Repeated inspections allow to determine realistic corrosion rates for the inspected pipelines. 相似文献