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为便于准确地执行JB4708-92《钢制压力容器焊接工艺评定》中关于组合焊缝的焊接工艺评定的有关规定,本文就不同种类的组合焊缝的评定方法分别进行了讨论,对于全焊 组合焊缝,专门举例说明了进行评定的具体试件制作方法。 相似文献
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AWS D1.1《钢结构焊接规范》和AWS D1.6《不锈钢结构焊接规范》对槽焊缝的焊接工艺评定、焊工资质评定和焊接操作都进行了明确规定,但是在实际应用中仍然存在将槽焊缝的焊接操作和坡口焊缝或者角焊缝的焊接操作相互混淆的情况,槽焊缝缺陷导致的质量事件时有发生。针对槽焊缝返修焊接工艺制定及焊接操作技术等问题,总结分析工程现场钢结构及模块施工中实际案例,在常规焊缝返修工作的实践基础上,根据AWS焊接规范要求,对槽焊缝的返修工作提出了专业性的方法,包括缺陷去除、坡口制备和返修焊接工艺制定等,并详细介绍了不同焊接位置下槽焊缝返修的焊接操作技术。 相似文献
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针对奥氏体不锈钢管道焊缝焊后热处理的问题进行探讨,通过焊接工艺评定和工程实践,证明了对奥氏体不锈钢管道焊缝进行焊后热处理的可行性,并提出了焊后热处理的注意事项。 相似文献
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为了提高弧焊机器人的焊缝跟踪精度,提出了一种新的焊缝跟踪精度的评价方法,建立了基于三维空间焊缝的精度评价模型,该模型建立了焊接电流、焊接速度和焊枪高度等多个焊接工艺参数与焊缝跟踪精度之间的模型关系. 基于该模型,通过MATLAB对该模型进行仿真分析,验证了所提出精度分析方法和精度模型的正确性及有效性. 结果表明,在焊缝跟踪过程中焊接电流和焊接速度对焊缝跟踪精度影响明显. 该精度分析方法对于焊缝跟踪精度的评价具有一定的参照意义,并且在焊接工艺参数的合理选择时对焊缝跟踪精度具有重要影响. 相似文献
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本文介绍了焊缝金属强度匹配方式和类型,分析了焊缝金属强度匹配方式的工艺焊接性,列举了焊缝金属强度匹配应用实例。结果表明,焊缝的强度匹配方式有5种,拉伸试样断口部位各异。5种焊缝的强度匹配方式中,低强匹配和组合匹配方式的工艺焊接性得到改善,施工成本降低,接头的抗脆断性能能够控制;等韧性匹配的工艺焊接性取决于所用钢种和行业规定,施工条件较严格,成本较高,接头的抗脆断性能比较优良。14MnM oNbB钢低匹配专用焊条J506DP,可降低14MnMoNbB钢的临界预热温度50~70℃,改善了该钢的工艺焊接性;低匹配焊缝接头的强度已与母材等强,接头的安全性符合设计要求。组合匹配接头在综采支架立柱中应用表明,可使30MnNbXt钢在室温下焊接时不产生裂纹,而且在焊后状态下的使用性能完全符合产品技术条件要求。 相似文献
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采用4MeV直线加速器对厚壁(T≥50mm)焊接三通角焊缝的内部质量进行射线检验,如果照相工艺参数选择不当,不但严重影响焊缝缺陷的检出率,而且给底片评定和缺陷返修带来诸多不便,本文讨论了厚壁焊接三通角焊缝的射线照相工艺.1 焊接三通角焊缝的结构特点如图1所示,支管侧焊缝坡口,从腹部至肩部为0°~25°连续变化;而主管侧则依圆柱形态从与轴向正交断面变化到平行方向.焊接采取手工电弧焊,全焊透结构,在变位工装支持下挑立焊,外层以横焊盖面,属多层多道焊接.焊后镗掉内侧焊根或衬板. 相似文献
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熔化焊锅炉接管角焊缝的射线透照技术探讨 总被引:2,自引:0,他引:2
指出在接管角焊缝圆周方向上穿透厚度的变化率和倾斜投影造成的影象畸变是确定透照工艺和进行缺陷评定的难点所在。提出目前可以采用并使之标准化的、规范化透照方法,以弥补国内锅炉、压力容器行业在管座角焊缝焊接质量监控手段上的某些空白。 相似文献
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针对大直径厚壁圆柱管对接环焊缝的焊接问题,提出背面焊条电弧焊打底、清根、正面埋弧焊填充的组合焊工艺。为此,我们正确选择焊接工艺参数,合理把握焊接作业节奏,调整热输入,控制温度特征,从而削弱了接头的淬硬倾向,防止冷裂纹的产生。实践证明,全熔透组合焊的对接环焊缝符合GB/T11345中一级质量标准。 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):275-278
AbstractIt is demonstrated how the current trend towards high speed, narrow groove welding, and the corresponding shift towards high base metal dilution, may result in decreased weldability for 6xxx and 7xxx aluminium alloys. In particular, variations in base metal dilution for extrusion alloys 6082 and 7108 have been examined for welds made with 5183, 5356, 5654, and 4043 filler alloys, particularly at high dilution ratios. The less common filler alloys 5039 and Safra 66 are also considered. Dilution curves superimposed upon existing hot cracking curves show that cracking susceptibility increases rapidly with base metal dilution for these alloys. Establishing an upper limit for dilution to avoid hot cracking, for a specific engineering application, also requires a knowledge of restraining conditions. For conditions of high restraint, i.e. rigid fixturing, enforcing an upper limit for base metal dilution will become critical. The effect of dilution on weld strength is also considered. 相似文献
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针对目前车身点焊质量检测广泛采用的破坏性检验和无损检测方法中存在离线、小样本、检测成本高的缺点,借助于伺服焊枪编码器的位移反馈特性提出一种基于压痕的焊点质量在线检测方法.试验建立包括机器人及控制器、伺服焊枪和焊接控制器在内的点焊试验系统,利用伺服焊枪编码器位置反馈特性在线获取焊点压痕,通过PLC位移采集系统在线标定压痕获取精度,最后以0.8 mm的普通低碳钢板(GMW2)为例,完成基于压痕的焊点质量在线评价.试验结果证明,伺服焊枪编码器位置反馈精度能够满足焊点压痕测量要求,点焊接头质量在线评价的准确率符合实际生产要求,文中提出的基于压痕的点焊质量在线评价方法可以实现点焊接头的在线检测. 相似文献
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《Science & Technology of Welding & Joining》2013,18(6):744-749
AbstractFinding suitable characteristic parameters of topside weld pool to reflect the penetration is a key work in weld shape control. In this paper, by analysing the molten metal volume, the relationship between topside weld bead shape and penetration in pulsed gas metal arc welding (PGMAW) is revealed, and then several weld bead characteristic parameters (WBCPs) are proposed to determine the penetration. However, these WBCPs are difficult to be obtained in real time, because continuous solidifying of weld pool forms the weld bead, and the WBCPs can be reflected by the weld pool geometry. Therefore, some weld pool characteristic parameters (WPCPs) are proposed to replace the WBCPs. Furthermore, a visual system is established and a series of image processing arithmetics are developed to extract the WPCPs. 相似文献
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介绍了PWT外焊自动根焊和RWS自动焊填盖技术,重点讲述了自动焊技术中焊接材料的选用、焊接工艺参数的计算和焊接质量的控制。 相似文献
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随着焊缝强度的提高其韧性呈曲线变化,这与组织的变化有关,故提高韧性的途径有:减少先共析铁素体,增加针状铁素体;减少上贝氏体和M-A组元,增加下贝氏体;依靠夹杂物的形核核心作用;在铁素体组织中依靠钛硼复合韧化,在贝氏体组织中则只加钛不加硼,硼有抑制钛的形核核心作用;降低非形核夹杂物的含量;加入适量镍,韧化基体,它对各种强度级别的焊缝都有好的作用。 相似文献
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1 INTRODUCTIONTheactivatingTIGwelding (A TIG)wasfirstlydevelopedbyPatonWeldingInstitute ,Ukraine ,inthe 196 0s[1,2 ] .Itisnotuntiltheendof 1990sthatA TIGweldinghasbeenwidelyresearchedinEuropeandUS ,forexample ,TWIandEWI[3] .Thefluxes ,whichweredevelopedbyEWI ,havebeenappliedintheUSNavyshipbuildingindustry[4 ] .Theprincipleofthistechniqueisthatathincoatingofactivatingfluxiscoatedonthesurfaceofthebasemetalbeforeweld ing .ComparedwiththeconventionalTIGwelding ,the penetrationca… 相似文献
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Jae Hak Kim Jun Seok Seo Hee Jin Kim Hoi Soo Ryoo Ka Hee Kim Moo Young Huh 《Metals and Materials International》2008,14(2):239-245
The effect of microstructures on weld metal cold cracking has been studied using flux-cored are welding (FCAW) wires with
a 600 MPa strength level. Two FCAW wires were prepared by controlling the Ni content to allow a sufficient variation in weld
microstructures, but with little change in the weld metal strength. The microstructural analysis showed that there was a significant
difference in the proportions of the microstructural constituents of the weld microstructure. The 1.5%Ni wire resulted in
a weld microstructure with a lower grain boundary ferrite (GF) content associated with an increased proportion of acicular
ferrite (AF) than the 0% Ni wire. The GF contents of 0%Ni and 1.5%Ni weld metal were measured to be 19% and 6%, respectively.
The cold crack susceptibility of these two FCAW wires was evaluated using the gapped bead-on-plate (G-BOP) test at the two
different levels of diffusible hydrogen content As a result of the G-BOP tests, it was demonstrated that the 1.5%Ni wire had
better resistance to cold cracking than the 0% Ni wire because its weld deposit had a lower GF phase content. This implies
that, in addition to the hydrogen control approach, microstructural modification can be pursued to develop new welding consumables
with an improved resistance to cold cracking. In the discussion, the detrimental effect of GF against cold cracking is addressed
based on the microstructural characteristics of cold cracks in ferritic weld metal. 相似文献
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介绍了PWT外焊自动根焊和RWS自动焊填盖技术,重点讲述了自动焊技术中焊接材料的选用、焊接工艺参数的计算和焊接质量的控制。 相似文献
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This study developed a sequential coupling finite element procedure to predict residual stresses of steel pipes with longitudinal wela\ circumferential weld and spiral weld.The results show that the residual stress in heat affected zone(HAZ)is higher than that in weld for spiral weld pipe.For the circumferential weld pipe and spiral weld pipe,the residual stress in inner surface is higher than that in outer surface.However,for the spiral weld pipe,the residual stress in inner surface is smaller than that in outer surface.The hoop residual stress of circumferential weld pipe is higher than that of longitudinal weld pipe,while the axial residual stress of circumferential weld pipe is smaller than that of longitudinal weld pipe.The hoop stresses for circumferential weld pipe and axial stress for longitudinal weld pipe have exceeded the yield strength of base metal.With the increase of helix angle,the hoop stress decreases while the axial stress increases.For the spiral pipe(α=30° to 50°),both the hoop stress and axial stress are relatively small.The spiral pipe(helix angle ranging from 30° to 50°) is helpful to reduce stress corrosion cracking(SCC) and it is recommended to manufacture the steel pipe. 相似文献