铝合金结构件焊缝质量涡流及X射线检测对比研究

涡流检测方法具有设备简单、检测速度快、灵敏度高、非接触式检测等优点,能及时检测焊缝质量情况,有效检测焊缝是否存在未焊透、焊接裂纹等缺陷,以分析确定焊缝内的潜在风险,现已成为铝合金结构件焊缝的有效检测手段。采用多频涡流检测技术,配合新型无方向性电扰动涡流传感器及X射线探伤仪,并制作铝合金结构件焊缝人工缺陷,通过对比试验两种不同的检测方法,分析两种方法的优劣。试验结果表明,多频涡流检测技术配合新型无方向性电扰动涡流传感器能够满足检测要求,减小焊缝表面焊道的凹凸不平产生的干扰影响,并且全面地发现缺陷;相比之下,虽然X射线检测结果更为直观,但检测速度较慢,不适合现场应用及缺陷快速定位。     

不锈钢焊缝的涡流正交探头检测试验

涡流检测方法可以在不去除涂层或者防腐层的情况下对焊缝实施检测,然而关于特种设备焊缝的涡流检测技术的应用较少。以304不锈钢焊缝为研究对象,通过自制正交焊缝检测探头开展检测试验,并对其特性进行研究,以供同行交流。     

压力容器无损检测--涡流检测技术

综述了压力容器用管材制造和压力容器使用过程中的涡流检测技术，包括制造过程中的铁磁性钢管和非铁磁性金属管材的涡流检测技术、在用铁磁性钢管的远场涡流检测技术、在用非铁磁性金属管的涡流检测技术和金属压力容器壳体焊缝表面裂纹的复平面分析涡流检测技术。     

动车变流器安装座焊缝涡流检测的灵敏度验证

通过介绍动车变流器安装座焊缝涡流检测的灵敏度验证方法和验证过程,证明了在不脱漆状态下采用涡流方法检测焊缝疲劳缺陷的可行性,阐明了焊缝疲劳缺陷涡流检测的工艺要点。     

铝合金焊缝裂纹涡流检测系统设计及试验研究

针对铝合金焊缝表面及近表面裂纹缺陷涡流检测时缺陷信号难于识别问题,开发了基于ARM的铝合金焊缝裂纹涡流检测系统,设计研制了铝合金焊缝涡流检测探头,开展了带有预制裂纹的铝合金焊缝涡流检测试验。试验结果表明:利用研发的铝合金焊缝涡流检测系统及探头能够有效实现对铝合金焊缝表面及近表面裂纹的检测和判别,其中噪声信号阻抗图平行于实部分量轴线,缺陷信号阻抗图呈现"8字"形且和噪声信号具有较大的相位差,具有较高的信噪比。对非铁磁性材料焊缝的涡流检测系统的开发和探头的研制具有一定的工程应用价值。     

管板焊缝结构涡流检测端部效应抑制仿真试验

针对管板角焊缝结构涡流检测的特点,研究了影响常规涡流检测实施的相关因素(包括外形、材料等),并在此基础上采用ANSYS有限元仿真技术对专用的传感器进行了优化设计,增加了永磁磁化单元,结合抑制涡流检测端部效应的信号处理方法,减小了端部检测盲区范围,提高了焊缝缺陷的检测精度。仿真和试验结果表明,通过对管壁和焊缝施加磁化及对检测信号进行差分处理,能够实现薄壁管管板角焊缝深层缺陷的检测,证明了管板焊缝结构涡流检测的可行性,提高了管板涡流检测的效率。     

超导电缆不锈钢护套焊缝的涡流阵列检测

针对常规无损检测方法无法满足超导电缆不锈钢护套焊缝检测要求以及较高检测效率要求的问题,采用涡流阵列检测技术对电缆不锈钢护套焊缝进行检测,通过研究检测频率、提离效应等对检测信号的影响,确定适用于薄壁不锈钢护套焊缝检测的涡流阵列检测工艺,分别在带有人工缺陷和自然缺陷的试样上进行工艺验证,同时采用X射线和工业计算机层析成像等检测方法验证涡流阵列检测工艺的有效性,为后续实现超导电缆不锈钢护套焊缝的在线实时检测提供依据。     

汽车钢号防伪检测技术

介绍了采用交流磁场涡流检测技术，并利用WELD SCOPE焊缝裂纹探伤仪在不破坏油漆的情况下，检测伪造汽车钢号的方法.     

核电厂反应堆水池覆面焊缝的阵列涡流检测

核电厂反应堆水池普遍采用不锈钢覆面结构，在建造和运行期间均发生过泄漏现象。从覆面结构特点出发，开展了覆面焊缝的阵列涡流检测试验，主要探讨平面对接焊缝中人工刻槽和孔型缺陷的可检出性。结果验证了阵列涡流用于反应堆水池焊缝缺陷检测的可行性。通过对某电厂在役检测期间的反应堆水池焊缝进行阵列涡流检测，总结了其特点及存在的问题，可为核电厂在役期间水池查漏提供参考建议。     

基于变面积式双涡流传感器的焊缝跟踪系统

针对薄板对接接头错边问题以及搭接接头难以实现焊缝跟踪问题,提出了一种基于变面积式双涡流传感器的焊缝跟踪方法.将两变面积式涡流传感器置于焊缝的一侧,通过双传感器分别检测高低和左右的位置信息,相互补偿得到独立的偏差信号以实现焊缝跟踪.分析了变面积式涡流传感器的原理,利用响应面法拟合响应曲面,进行变量分离,得到了输出电压信号与面积的关系式.最后,搭建简易平台进行了薄板对接及搭接的焊缝跟踪试验.结果表明,双涡流传感器焊缝跟踪方法具有可行性与正确性,为自动焊缝跟踪技术研究提供了新的研究方向.     

带涂层焊缝的电磁涡流检测

采用电磁涡流法对16MnR钢焊缝试件进行了涡流检测。得出在焊缝表面较平整情况下,检测裂纹的能力同涂层厚度间的定性关系。渗透检测对比结果表明,电磁涡流法在表面涂层平均厚度不大于500μm时,可检出各种形式焊缝表面的裂纹、气孔和咬边等缺陷。     

超高强度钢与镀锌双相钢电阻点焊接头强度试验

试验研究了超高强度硼钢板/镀锌双相钢板的电阻点焊接头质量缺陷及其产生原因,通过正交试验设计,重点讨论了焊接电流、通电时间和电极压力对点焊接头强度的影响.结果表明:超高强度硼钢板/镀锌双相钢点焊中超高强度钢板侧更易出现飞溅和烧穿问题,通电时间和焊接电流强度时点焊接头拉剪强度影响显著,这类钢板组合的焊接应优先采用大电流、短...     

高强铝合金脉冲变极性等离子弧焊接头组织与性能

采用脉冲变极性等离子弧焊对厚度10 mm的7075铝合金进行焊接,利用光学显微镜、扫描电子显微镜、X射线衍射仪、万能拉伸试验机和显微硬度仪对焊缝的显微组织和焊接接头的力学性能进行了分析和测试,研究植入脉冲对焊接接头组织及力学性能的影响.结果表明,植入脉冲后焊接接头成形良好,由于高低频脉冲的周期性变化引起熔池液体强烈的搅拌作用,细化了焊缝的显微组织,强化相T相得到细化,提高了焊缝的抗拉强度和显微硬度,焊缝处的抗拉强度为397.9 MPa,约为母材强度的67.5%,比未植入脉冲时提高了5.13%,焊缝质量有所提高.     

超长寿命区间16Mn钢焊接接头疲劳性能

使用自行研制的TJU-HJ-Ⅰ型超声疲劳试验系统装置进行了16 Mn钢母材和焊接接头试件的超声疲劳性能试验,以探索其在超长疲劳寿命区间的疲劳行为.结果表明,无论母材还是焊接接头,其S-N曲线都是一条连续下降的曲线;在106～107循环周次范围内焊接接头不存在传统概念上的疲劳极限,载荷循环周次超过107甚至109以后,试件依然发生疲劳断裂.在超长寿命区间,焊接接头疲劳强度远低于母材的疲劳强度.使用现有疲劳极限数据去设计工作在超长寿命区间的焊接结构件是很危险的.     

Effect of the structure and stress state on the magnetic properties of metal in different zones of welded pipes of large diameter

The existence of an extensive network of main pipelines, both already operating and being constructed, which are exploited under complex climatic conditions, specifies the need for the development of methods of a nondestructive control for testing the current state of both the pipes themselves and the welded joints in the process of manufacture and subsequent service. In this work, we give the results of microstructural studies, as well as the mechanical and magnetic properties of different zones of welded joints (base metal, heat-affected zone, and the weld) of pipe steels of the strength classes X70 and X80 produced using the method of controlled rolling. The influence of different modes of loading on the magnetic characteristic of the metal of all three zones of welded joints has been investigated. The magnetic parameters that unambiguously characterize changes in the stress-strain state of the separate zones of the welded joint (weld, heat-affected zone, base metal) have been determined in certain ranges of the applied stresses.     

一种用于焊接结构超声成像检测的SH导波换能器

板中水平剪切导波可用于焊接结构板材远距离成像检测,超声SH导波换能器的性能对较大尺度焊接结构板材超声导波成像检测至关重要.对板中SH导波进行了动力学分析,并结合半波长条件设计了合理的斜楔角度、压电晶片频率及尺寸等导波换能器的重要参数,通过加前背衬、取消后背衬、楔块前沿设置锯齿槽等措施,简化了换能器的工艺结构,减小了换能器内部回波干扰,提高了检测灵敏度.结果表明,设计研发的SH导波换能器激发的导波有较强的检测能力,可用于对较为复杂的T形一对焊焊接结构板材进行成像检测,能够有效表征焊接结构板材中与导波波长尺寸量级相当的缺陷,其性能指标达到了较大尺度焊接结构板材成像检测的要求.为开展较大尺度焊接结构超声导波成像检测奠定了基础.     

TLB型复杂焊接结构超声SH导波成像检测

通过光弹试验分析超声水平剪切(shear horizontal,SH)导波具有优异传播性能,构建了超声导波成像检测系统,基于合成孔径聚焦对超声SH导波用于TLB型式复杂焊接结构成像检测进行了重点研究.结果表明,基于合成孔径聚焦的超声SH导波成像用于TLB型式复杂焊接结构构件检测是可行的,检测图像能够表征板材中区域特征,对焊缝有较好的定位功能,但在焊缝之后会形成长约100 mm的固有散射盲区.文中为进一步提高TLB型式复杂焊接结构超声导波成像检测应用水平提供了基础.     

Comparison of formability of friction stir welded and laser welded dual phase 590 steel sheets

Abstract

The formability of welded dual phase 590 (DP 590) steel sheets was investigated, using both friction stir welding and laser welding. Similar and dissimilar gauge sheets were joined using both processes. The laser welded sheets were produced under process conditions typical of industrial production of tailor welded blanks. The friction stir welded specimens were produced in a lab, where different tool rotational speeds and translation speeds were investigated in order to obtain good weld properties. The formability of the welded sheets was evaluated using a series of mechanical tests, including transverse tension and plane strain formability testing. Friction stir welded specimens performed about the same as laser welded specimens in transverse tension testing; however, hardness profiles showed that the laser welds had greater peak hardness than the friction stir welds. Therefore plane strain formability tests were performed with the welds oriented along the major strain direction. When this type of weld stretching was performed the friction stir welded sheets were shown to be ～20% more formable than the laser welded sheets.     

Effect of Postweld Aging Treatment on Fatigue Behavior of Pulsed Current Welded AA7075 Aluminum Alloy Joints

This article reports the effect of postweld aging treatment on fatigue behavior of pulsed current welded AA 7075 aluminum alloy joints. AA7075 aluminum alloy (Al-Zn-Mg-Cu alloy) has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers, and railway transport systems. The preferred welding processes of AA7075 aluminum alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 10 mm thickness have been used as the base material for preparing multipass welded joints. Single V butt joint configuration has been prepared for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt.%)) grade aluminum alloy. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW), and (iv) pulsed current GMAW (PCGMAW) processes. Argon (99.99% pure) has been used as the shielding gas. Rotary bending fatigue testing machine has been used to evaluate fatigue behavior of the welded joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. Grain refinement is accompanied by an increase in fatigue life and endurance limit. Simple postweld aging treatment applied to the joints is found to be beneficial to enhance the fatigue performance of the welded joints.     

热处理对100mm厚TC4钛合金电子束焊接接头性能的影响

针对100mm厚TC4钛合金板进行电子束对接,焊后对接头分别进行850℃再结晶退火和920℃+2 h和500℃+4 h固溶时效热处理,观察接头的微观形貌,测试其硬度和拉伸性能。结果表明,经过再结晶退火后,焊缝中部开始出现β相晶界,热影响区熔合线附近的针状α′相变少,β相等轴晶界开始出现。经过920℃+2 h和500℃+4 h固溶时效处理后,焊缝中部和底部都出现明显的β相晶界,热影响区熔合线附近的β相等轴晶界明显可见,为细片层β转变组织。力学性能测试表明,经过固溶时效热处理的接头焊缝区、热影响区及母材区的显微硬度明显高于焊态,其接头拉伸强度比焊态提升11.3%,屈服强度比焊态提升17.2%,但接头延伸率比焊态降低近59%。