带极电渣堆焊在双金属冶金复合管纵缝覆层焊接中的应用

双金属冶金复合管的焊接工艺包括基层(碳钢层)焊接和覆层(不锈钢等合金层)焊接两个部分;在进行基层内焊埋弧焊接时,为保护不锈钢覆层的坡口不被基层内焊埋弧焊烧损,需匹配相应的焊接参数,但会导致基层内焊缝边沿与覆层坡口间出现沟槽,若直接在基层内焊缝上进行覆层的带极堆焊,将会在覆层焊缝中出现类似未熔合/夹渣类缺陷;通过采用不同覆层焊接工艺进行对比试验,选择覆层焊接采用自动TIG焊焊接基层内焊缝边沿+带极电渣堆焊工艺,该覆层焊接工艺可有效减少该类缺陷的产生;并通过试验验证了该工艺条件下的焊接接头的力学性能及覆层焊缝抗腐蚀性能等均满足标准要求。     

尿素合成塔焊接质量的同型多胶片射线检测方法

新型 1 2 0 0 mm尿素合成塔系多层包扎高压容器 ,塔壁由 1 7层板材构成 ,由内向外分成两部分 ,内层为耐腐蚀衬里板 ,由单层超低碳不锈钢板构成 ,材料为 31 6L,板厚 8mm;外层为承压部分 ,由盲层板(单层 ,厚度为 6mm)、内筒板 (单层 ,厚度为 1 2 mm)和层板 ( 1 4层 ,每层厚度为 6mm)构成 ,材料分别为碳钢和 1 6Mn R。塔壁总厚度为 1 1 0 mm,塔体由环焊缝连接而成。环焊缝开双 U型坡口 ,坡口面由手工堆焊层覆盖 ,厚度 2～ 3mm(图 1 )。图 1　坡口形式以及焊接和探伤程序合成塔系内部为腐蚀介质的高压容器 ,内外层的焊接质量直接影响合成塔…     

ENiCrMo-3等级镍基合金单层带极电渣堆焊工艺研究

针对产品技术要求中ENiCrMo-3等级镍基合金堆焊层厚度大于等于4.5 mm、堆焊层表面及堆焊层表面以下3.2 mm处化学成分需满足ASME规范Ⅱ卷C篇SFA-5.11 ENiCrMo-3和弯曲性能合格的条款,采用单层带极电渣堆焊工艺增加堆焊厚度的方法取代常规工艺中采用双层带极电渣堆焊的方法,在平板上和筒体内壁两种工况下进行堆焊试验,摸索出了ENiCrMo-3等级镍基合金焊带单层电渣堆焊焊接工艺参数。试验结果表明,除焊接热输入相关变量外,上坡量对焊缝成形尤为重要,对比平板堆焊和内径1 620 mm筒体内壁堆焊的焊接参数可知,单层堆焊厚度大于等于4.5 mm时,两种结构下的适用焊接参数差异较大,平板堆焊参数不能适用于筒体内壁堆焊。     

反应堆压力容器下底圆J型坡口隔离层堆焊预热问题分析及其处理

介绍了反应堆压力容器下底圆中子测量管的焊接工艺.基于某制造厂发生的该焊缝相关的下底圆J型坡口隔离层堆焊预热质量问题,分析了预热、层间温度等焊缝质量影响要素及该质量问题的处理方案,为今后类似问题的处理和提高J型坡口隔离层的堆焊质量提供参考.     

14Cr1MoR焊缝堆焊隔离层工艺的研究

针对某设备中14Cr1MoR焊接接头所需的特殊使用性能,选择镍基焊材对母材进行坡口堆焊隔离层并填充焊接,实现了该焊缝将来检修再次焊接后,无需进行消除应力热处理的目的。     

坡口形式对半管夹套焊接温度和残余应力的影响

半管夹套焊接时不可避免产生残余应力,容易导致其焊接部位开裂泄漏.文中对不同坡口形式的半管夹套进行焊接试验,并利用有限元软件ABAQUS对焊接温度场及残余应力进行数值模拟.结果表明,不开坡口,加热温度不足以使夹套和筒体接触界面的金属完全熔化;开2 mm平行坡口时,焊缝根部温度未达到熔点,焊缝金属流动不足以填充根部间隙,产生未焊透;开45°外坡口,能保证完全焊透,且焊缝成型较好,焊缝根部的残余应力比不开坡口降低33%,筒体残余应力整体降低35%,有利于降低应力腐蚀开裂的敏感性.在实际焊接时,应开坡口焊接,禁止不开坡口或采用2 mm平行坡口.     

工艺参数对带极单层电渣堆焊层成分、成形及性能的影响

针对加氢反应器部件的焊接,采用单层电渣堆焊技术和国产焊带与焊剂,研究了堆焊工艺参数对堆焊层成分、成形及性能的影响。分析了4. 0～4. 5 mm,4. 5～5. 0 mm,5. 0～5. 5 mm,5. 5～6. 0 mm等四种厚度的堆焊层中主要合金元素的含量,以及分析了距离母材表面0. 5 mm及以上的堆焊层金属中合金成分的分布特点及稳定性。测试了不同厚度堆焊层中铁素体含量及其分布特点,控制堆焊层厚度为4. 0～5. 5 mm可以满足铁素体含量3～8 FN的技术要求。在合适的工艺参数范围内,堆焊层表面成形良好无缺陷,化学成分、铁素体含量及侧弯性能均满足技术要求。     

12Cr13与304L异种不锈钢焊接工艺研究

核反应堆控制棒驱动机构用材料12Cr13与304L异种不锈钢的焊接质量对驱动机构的安全性有重要影响。为了得到综合性能较好的焊接接头,根据不同的热处理制度和接头设计确定两个不同的实验方案,均选用ERNi Cr Fe-7A镍基焊丝,采用钨极氩弧焊工艺,通过在12Cr13上堆焊不同厚度的隔离层、经不同热处理后再坡口对接。采用光学显微镜观察焊接接头的显微组织并进行拉伸试验、弯曲试验以及硬度试验,对12Cr13热影响区进行0℃冲击试验。结果表明,采用堆焊4 mm隔离层+调质处理的方案能获得质量较好的焊接接头,足够的隔离层厚度能减少最终焊接热循环对焊接性较差的母材的影响,调质处理有效降低了12Cr13热影响区的硬度,对接焊缝与304L母材硬度较为均匀,热影响区为均匀回火索氏体组织,0℃冲击功达到了平均152 J。     

LAO反应器用P355NH/NL2复合板的焊接及热处理

分析P355 NH/NL2+SB625(UNS N08904)复合板材料特性,进行了多项焊接工艺评定试验,确定了合理的焊接及热处理工艺参数。试验表明,基层材料使用焊材FLUXOCORD41.1/OP 121TT/W后,其力学性能及低温冲击性能均满足设计要求;基层焊缝焊接适用焊材为W607DR H09MnNiDR/SJ208DR,采用双层带极埋弧堆焊;过渡层堆焊焊材为H309MoL,表层堆焊焊材为H904L,堆焊厚度3+3.5 mm。小电压、小电流、小的输入量、合理并经过评定的热处理工艺规范可有效改善接头的低温性能。     

9%Cr钢表面激光熔覆制备低Cr合金改性层组织及Cr含量分析

目的通过对比分析1CrMo合金激光熔覆和埋弧堆焊层中Cr元素含量分布,研究激光熔覆替代堆焊技术用于9%Cr钢汽轮机转子轴颈表面改性的可行性。方法采用与1CrMo合金焊丝成分相同的合金粉末作为激光熔覆材料,利用半导体激光熔覆系统在9%Cr钢表面制备低Cr合金熔覆层。用直读光谱仪、金相显微镜、扫描电镜和显微硬度计等仪器,分析熔覆层中Cr含量分布、熔覆层组织结构和性能,并与堆焊层进行了对比。结果利用激光熔覆技术成功在9%Cr钢表面制备了不同厚度、无缺陷的1CrMo合金熔覆层,熔覆层组织主要由铁素体和颗粒状碳化物相构成。多层熔覆层硬度在220～250HV0.3之间,与基体硬度接近。激光熔覆可有效减少基体对熔覆层的稀释,熔覆层中Cr含量降低明显,在熔覆层约2 mm厚处的Cr含量已低于2%的工作面Cr含量要求,而堆焊需8 mm左右才能达到相同的降Cr效果,激光熔覆所需熔覆层数明显少于埋弧堆焊法的堆焊层数。结论与堆焊相比,激光熔覆用于9%Cr钢汽轮机转子轴颈表面改性需熔覆层数少,表面降Cr效率更高。     

Numerical Investigation on Residual Stresses of the Safe-End/Nozzle Dissimilar Metal Welded Joint in CAP1400 Nuclear Power Plants

The residual stress evolution in a safe-end/nozzle dissimilar metal welded joint of CAP1400 nuclear power plants was investigated in the manufacturing process by finite element simulation. A finite element model, including cladding, buttering, post-weld heat treatment (PWHT) and dissimilar metal multi-pass welding, is developed based on SYSWELD software to investigate the evolution of residual stress in the aforementioned manufacturing process. The results reveal a large tensile axial residual stress, which exists at the weld zone on the inner surface, leads to a high sensitivity to stress corrosion cracking (SCC). PWHT process before dissimilar metal multi-pass welding process has a great influence on the magnitude and distribution of final axial residual stress. The risk of SCC on the inner surface of the pipe will increase if PWHT process is not taken into account. Therefore, such crucial thermal manufacturing process such as cladding, buttering and post-weld heat treatment, besides the multi-pass welding process, should be considered in the numerical model in order to accurately predict the distribution and the magnitude of the residual stress.     

Investigations into the tendency to stress corrosion of joints welded in austenitic and duplex steels

Austenitic stainless steel is welded as a cladding on the inner surface of a reactor pressure vessel (RPV) made of low alloy steel. In order to assess the structural integrity of the RPV precisely, the residual stress distribution caused by weld-overlay cladding and post-weld heat treatment (PWHT) is evaluated. Since the cladding layer is very thin compared to the vessel wall, it is necessary to evaluate the residual stress distribution around the weld fusion line, which can be very steep. In this study, cladded specimens were fabricated using different welding methods. Residual stress measurements using both sectioning and deep hole drilling (DHD) methods were then performed to evaluate the residual stress distributions through the weld fusion line. Three-dimensional thermal-elastic-plastic-creep analyses based on the finite element method were also conducted to evaluate the residual stress caused by weld-overlay cladding and PWHT. It was shown that analytical results provided reasonable agreements on weld residual stress with experimental results. It was also clarified that the main cause of residual stress due to welding and PWHT was the difference of thermal expansion between weld and base metals.     

钢制安全壳焊后热处理工程应用与建议

根据钢制安全壳的结构尺寸、建造方式和焊后热处理要求,分析对比了适宜钢制安全壳焊后热处理的加热方式,并通过应用证明了局部焊后热处理的可行性。结合工程经验,提出了推动厚度小于60 mm的SA-738 Gr.B钢板免除焊后热处理,或采用超声波冲击处理代替焊后热处理的建议。     

Finite Element Analysis of High Temperature Piping Creep for Considering the Effect of Inner Pressure and Welding Residual Stress

利用大型有限元分析软件Abaqus的多次顺次耦合功能,先对P91钢高温主蒸汽管道焊接接头焊态和焊后热处理状态进行残余应力分析, 然后采用Norton蠕变本构关系,根据P91耐热钢在625℃下焊缝、热影响区和母材的不同蠕变参数,对内压以及内压与热处理后残余应力共同作用下的接头蠕变进行有限元分析,分别得到了焊接残余应力和焊后热处理残余应力的分布规律,同时预测了在高温环境下服役105h后蠕变应变分布. 结果表明,由于高温管道的壁厚以及约束等影响, 焊后产生了较大的焊接残余应力,通过焊后热处理可以有效地降低焊接残余应力.但由于热处理残余应力的存在, 仍对高温管道焊接接头的蠕变有较大影响,并且在焊缝与热影响区的交界处存在着较大的蠕变应变.     

电渣焊焊缝收缩规律及结构下料尺寸的确定

通过测量I形对接接口管极电渣焊焊接缝的向收缩量,分析其收缩量大小与焊缝长度、焊件厚度和组对间隙之间的关系,为电渣焊焊接结构下料尺寸的确定提供了依据。     

核用SA508-3钢特厚板焊后热处理有限元分析

为了得到SA508-3钢特厚板焊接残余应力分布及焊后热处理对残余应力分布的影响,利用有限元方法对焊接及焊后热处理进行了模拟计算,计算结果表明:焊后热处理对试板焊接应力分布趋势影响较小,但焊后热处理可以大大减小接头应力数值,其中,纵向应力最大减小幅度为72%,横向应力最大减小幅度为70%;焊接接头存在应力分布准稳定区,且接头内部残余应力水平最小,其次为接头上表面,接头下表面应力水平最大;通过残余应力测定试验与模拟结果比对,两者结果吻合度很高,说明计算模型及计算方法可靠,可以指导实际SA508-3钢特厚板焊后热处理生产.     

Effect of PTA Hardfaced Interlayer Thickness on Ballistic Performance of Shielded Metal Arc Welded Armor Steel Welds

Ballistic performance of armor steel welds is very poor due to the usage of low strength and low hardness austenitic stainless steel fillers, which are traditionally used to avoid hydrogen induced cracking. In the present investigation, an attempt has been made to study the effect of plasma transferred arc hardfaced interlayer thickness on ballistic performance of shielded metal arc welded armor steel weldments. The usefulness of austenitic stainless steel buttering layer on the armor grade quenched and tempered steel base metal was also considered in this study. Joints were fabricated using three different thickness (4, 5.5, and 7 mm) hardfaced middle layer by plasma transferred arc hardfacing process between the top and bottom layers of austenitic stainless steel using shielded metal arc welding process. Sandwiched joint, in addition with the buttering layer served the dual purpose of weld integrity and ballistic immunity due to the high hardness of hardfacing alloy and the energy absorbing capacity of soft backing weld deposits. This paper will provide some insight into the usefulness of austenitic stainless steel buttering layer on the weld integrity and plasma transferred arc hardfacing layer on ballistic performance enhancement of armor steel welds.     

碳钢-不锈钢缝焊包覆管的生产工艺及孔型设计

为了更好地发展我国小口径不锈钢缝焊包覆管生产,结合不锈钢缝焊管的生产经验,阐述不锈钢缝焊包覆管生产工艺流程及孔型设计方法,分别介绍了碳钢、不锈钢两种材料成型的经验数据。     

Influence of plate thickness on the mechanical properties of welded joints subjected to long-term postweld heat treatments

During their service lives, storage spheres, pressure vessels, and other welded structures are subjected frequently to postweld heat treatments (PWHT). Repeated treatments may result, in some cases, in a reduction in mechanical strength and fracture toughness of the weldments such that their mechanical properties may not meet the code specifications after those treatments. Steel ASTM-A-516 Gr 70 is used frequently to build storage spheres and pressure vessels in the petrochemical industry. In this context, the thickness of the plate is an important variable relative to the mechanical behavior of the welded joint after repeated PWHT. In a previous work (Pimenta and Bastian, JMEPEG, 2001, 10, pp. 192–202), the effect of the duration of a PWHT on the mechanical properties of a 65 mm thick plate was evaluated. In the present work, the effect of the same heat treatment on the properties of a 46.4 mm thick plate was evaluated and compared with those of the 65 mm thick plate. For this purpose, hardness measurements, tensile and Charpy V-notch impact tests, and a metallographic analysis were performed. The results show that both the base metal and heat-affected zone of the thinner plate present higher mechanical strength and impact resistance for all heat-treated conditions. The obtained mechanical properties were then compared with the requirements of the ASME Code, Section VIII.     

压力容器免除焊后热处理的最大厚度

工程实践表明现代钢材质量与焊接技术足以保证结构钢在更大厚度时免除焊后热处理,相关厚度值远高于现行规范源于工程经验的最大焊后热处理(Post weld heat treatment,PWHT)豁免厚度规定。从压力容器防脆断的角度出发,基于断裂力学原理,研究了材料最大PWHT豁免厚度的影响因素,结合Q345R钢性能数据,评价了具体厚度值的工程适用性,分析指出保守的防脆断条款是导致我国压力容器规范最大PWHT豁免厚度小于欧美规范的根本原因。