新型EH40船板钢大热输入量埋弧焊焊接接头组织性能研究

对EH40船板钢埋弧焊焊接接头的组织性能进行了试验分析。结果表明：以60kJ／cm的焊接热输入量焊接，接头的强度高于母材，热影响区（HAZ）没有出现焊接软化区。HAZ的低温冲击韧度低于母材。其中靠近熔合线的粗晶区冲击值（85．2J）最低，远离熔合线4mm处的冲击值（246．0J）已接近于母材。HAZ的组织状态对接头力学性能有较大影响，母材中Ti、Nb合金元素生成的碳、氮化合物在一定程度上改善了HAZ的韧性。     

Fe-Cr-Ni-Mo系高强钢焊接热影响区特征热循环曲线的建立与组织

开展了一种Fe-Cr-Ni-Mo系高强钢熔化极活性气体保护焊(MAG)焊接试验,同时测试了该高强钢的热物理性能参数和线膨胀系数,基于SYSWELD软件建立了该高强钢MAG焊接有限元模型,模拟了其MAG焊接热过程。通过对比模拟与试验获得的焊缝截面形貌、尺寸和焊接热循环曲线,建立了合适的双椭球MAG焊接热源模型。结合焊接接头硬度分布规律,确定了Fe-Cr-Ni-Mo系高强钢MAG焊接热影响区(HAZ)3个微区(粗晶区、细晶区和不完全淬火区)的范围,抽取了各微区的特征焊接热循环曲线。采用Gleeble3800热模拟机制备了各微区试样,显微组织和硬度对比结果表明,热模拟和实际焊接获得的HAZ各微区的显微组织和硬度吻合较好,抽取的各微区特征焊接热循环曲线较可靠。     

超超临界机组主蒸汽P92钢的焊接

根据华能玉环电厂超超临界机组主蒸汽管道P92钢的现场焊接实践,详细介绍了P92类新型铁素体耐热钢的焊接技术要点以及改善焊缝金属韧性、减小HAZ软化及Ⅳ型裂纹的具体措施.通过采用性能优良的焊材,采取"小线能量、快速连弧、小摆幅、薄焊层、多层多道焊"的操作方法,严格控制预热温度和层间温度,采用分区加热的热处理工艺,全过程旁站监督控制,从而得到了优良的焊缝.     

石化装置用16MnR(HIC)钢的焊接

评价了新型16MnR（HIC）钢的焊接性，从钢板的Pcm、Ccq以及焊接热影响区最高硬度值法等方面进行了分析；详细介绍了该钢在焊接过程中应注意的焊前准备、焊接规范等事项，同时研究了焊接线能量、退火温度、气割坡口和碳弧气刨以及焊缝返修对焊接接头的影响，并进行了16MnR（HIC）钢焊接接头的抗硫化物腐蚀开裂试验。     

装载机铲刀刃板焊接区域的组织与性能

采用冲击、拉伸和金相等试验方法，对ＣＯ２气体保护焊和Ａｒ＋ＣＯ２混合气体保护焊焊制的工程装载机铲刀刃板焊接接头区域的力学性能和显微组织进行了试验研究，并采用模拟焊接热循环的方法研究了不同峰值温度（Ｔｍ）和冷却时间（ｔ８／５）对ＨＱ１３０钢热影响区组织和冲击韧性的影响。试验结果表明，受焊接热循环影响，ＨＱ１３０钢ＨＡＺ存在回火软化区，该软化区中软化或失强最大的部位在峰值加热温度为Ａｃ１附近，在ＨＡＺ加热温度为Ａｃ１～Ａｃ３之间存在脆性区，冲击韧性明显降低。在焊接生产中应采用多层多道焊并应严格控制焊接线能量，以防止或减弱ＨＡＺ软化和脆化现象。     

焊接线能量对低碳贝氏体钢焊接接头性能的影响

根据低碳贝氏体钢焊接接头强韧性要求,选择所设计的一种烧结焊剂,采用不同的焊接线能量,对低碳贝氏体钢进行埋弧焊。通过金相分析和力学性能测试等方法,对其焊接接头的组织和性能进行了研究。结果表明:焊接线能量为26.86 kJ/cm时,焊接接头HAZ冲击韧性优异,达254 J,但焊缝区冲击韧性差,仅为86 J。而焊接线能量为29.45kJ/cm时,焊接接头的性能相对优异,焊缝区和HAZ的冲击功分别达167和159 J。在此焊接线能量下,焊缝区组织为粒状贝氏体,并且有弥散分布的夹杂物颗粒析出,单丝埋弧焊焊接线能量为29.45 k J/cm左右时最为适宜。     

07MnNiMoVDR钢制2000m3丙烯球罐冬季焊接施工的难点与应对措施

采用高强钢07MnNiMoVDR用于建造2000 m3丙烯低温球罐.由于高强钢07MnNiMoVDR在冬季焊接施工比较复杂,必须采取有效的防护措施.为确保焊接质量,针对国产高强钢07MnNiMoVDR焊接特性以及冬季焊接施工的难点,采取了焊前预热、焊接线能量控制、层间温度控制、焊后消氢热处理和焊接关键点等措施,有效保证...     

含铜时效钢气体保护焊热影响区的组织与性能

研究了含铜时效钢气体保护焊热影响区的组织与性能。结果表明，在试验所用热输入范围内（1．2～2．3kJ／mm），含铜时效钢具有良好的焊接性能。焊接接头的拉伸强度同母材相比没有明显差异，且HAZ拉伸强度对热输入变化不敏感；焊接热影响区具有较高的冲击韧性，熔合线是HAZ中韧性最差的部位；和传统调质型船体用钢相比，含铜时效钢HAZ硬化和软化现象不明显；热输入对含铜时效钢粗晶区组织影响显著，随着热输入的增大，粗晶区组织由细板条贝氏体向粗大的粒状贝氏体转变。     

不同线能量下低碳贝氏体钢焊接接头的组织及韧性

研究不同线能量下低碳贝氏体钢焊接接头的组织及冲击性能。试验结果表明:低碳贝氏体钢对接直缝焊接后,焊缝组织为针状铁素体和粒状贝氏体,HAZ的组织为贝氏体铁素体和粒状贝氏体,焊缝区和HAZ的晶粒都随着焊接线能量的减小而减小;焊缝的断裂形式多为韧性断裂,冲击性能均较好,当焊接线能量从24.8kJ/cm向28.2 kJ/cm增加,焊接接头的焊缝区和HAZ的冲击功呈先减小后增大的趋势。     

热输入对Q890D低合金高强钢焊接性能的影响

通过分析不同焊接热输入下Q890D钢板的焊接接头金相组织及热影响区硬度,考察了不同焊接热输入对其焊接接头强度、-20℃低温冲击吸收能量的影响。结果表明,Q890D钢在热影响区存在明显淬硬现象。当焊接热输入由低向高变化时,热影响区的硬度有上升趋势,而表面焊道的热影响区硬度远远高于打底焊道,说明多层多道焊时,后道焊缝对前道焊缝的热处理效果比较明显,减少了热影响区的淬硬组织。打底焊道的热影响区硬度低于焊缝及母材,存在焊后软化现象,焊接时需尽量避免过大的焊接热输入。焊缝金属中粗大贝氏体组织的增加,导致焊缝金属低温冲击吸收能量普遍低于热影响区。随着热输入的减小,焊接接头的抗拉强度和冲击吸收能量(包括焊缝、熔合线及HAZ)都有很大的提升。说明焊接热输入在一定范围内的变化对整个焊接接头强度及塑韧性有较大的影响。     

局部脆性区对直接淬火回火钢焊接热影响区断裂韧性的影响

通过焊接热模拟和厚板焊接接头ＣＴＯＤ断裂性能试验,研究了直接淬火回火钢焊接热影响区局部脆性区组织和性能及对厚板焊接接头断裂韧性的影响,结果表明,在γ＋α二相区的内再次加热的粗晶区（ＩＣＣＧＨＡＺ）具有最低冲击韧性值,是焊接接头中最薄弱环节,该区在原奥氏体晶界上分布着“项链”状,ＭＡ组元,引发多层焊热影响区脆断起裂,降低热影响区断裂韧性,局部脆性区韧性的高低和尺寸的大小是控制直接淬火回火钢多层焊热和     

INFLUENCE OF LOCAL BRITTLE ZONE ON THE FRACTURE TOUGHNESS OF HIGH-STRENGTH LOW-ALLOYED MULTIPASS WELD METALS

1.IntroductionManyillvestigatiolls[1--5]havefOllndthattilelocalbrittlezone(LBZ)playsanimportantroleinfyacturetoughnessofheat--affectedzoneinthebasemetalfornormalizedandthermomechanicallycontrolledprocessingsteels,aswellasdirectquellchedandtemperedsteels.Therearefewreportsaboutthisphellomellainhigh-strengtllmllltipassweldmetals.Inmultipasswelds,thereareprimaryweldmetalandweldmetalreheatedtovarioustemperaturesbythesubsequentbeads[6'71.Thereheatedregionfinderabeadcanbedividedintoacoarsegrainedz…     

Microstructure produced in the welding of steels for wide diameter pipes

Summary

The microstructure produced in the heat affected zone (HAZ) of steel weldments used in pipelines is evaluated. The shielded metal arc welding process was used to produce these weldments. While this welding process is characterised by multiple runs and low heat input, local brittle zones (LBZ) are present in the HAZ, which originate from a complex mechanism influenced by welding parameters and the chemical composition of the steel. Welding sequences which help to eliminate such LBZ are studied.     

BB503钢的焊接工艺及其性能和组织

研究了不同焊接工艺对微合金化Ti-Nb钢BB503钢板的组织和陛能的影响，寻求最佳的焊接工艺参数。用中、小线能量输入的手工电弧焊（sMAw）、CO2气体保护焊（GMAW）以及埋弧自动焊（SAW）3种不同工艺对25mm厚度的BB503铜板进行多道焊接，对焊接接头进行拉伸、弯曲、冲击、硬度等力学性能测试，并对其中典型试样的焊缝和热影响区的显微组织进行了观察和分析。试验结果表明，BB503钢对中、小线能量焊接的适应性良好。试验参数为实际生产中最佳焊接工艺的制订提供了依据。     

SAF2205双相不锈钢焊接热影响区在尿素介质中的腐蚀研究

研究了SAF2205双相不锈钢和尿素级316不锈钢对接焊热影响区在工业尿素合成介质中的耐蚀性.实验结果表明,焊接线能量对热影响区的耐蚀性有重要影响,腐蚀最重处是在距离熔合线3-6mm区域,局部腐蚀深度随线能量的增加而增大.SAF2205不锈钢焊接线能量对热影响区腐蚀的敏感程度比316L不锈钢大.     

Laser-TIG hybrid welding of ultra-fine grained steel

For improving the weldability of ultra-fine grained (UFG) steel, detailed experiments of laser-tungsten inert gas (TIG) hybrid welding were carried out on this material to investigate the effects of welding parameters on weld shape, microstructure, grain growth in heat-affected zone (HAZ) and mechanical performance. For the hybrid welds, increasing energy ratio of laser to arc (ER_LA) can narrow weld width, reduce the tendency of grain growth and ferrite grain coarsening in HAZ and also make the microstructure of fusion zone gradually change from coarse pearlite to fine martensite and bainite. The hybrid weld with low ER_LA has obvious softening zone in HAZ; while that with high ER_LA has no softening zone because of the low line energy. Compared to laser weld, under appropriate welding parameters hybrid weld with high ER_LA can obtain higher welding speed, better weld shape and more sound mechanical performance including similar tensile strength and higher toughness. These results demonstrated that laser-TIG hybrid welding is an effective process for UFG steel.     

Study on gas metal arc welding procedure of stainless steel

Summary

This paper describes an investigation of the creep rupture properties of welded joints produced from W-containing 9Cr-Mo-W steel. The creep rupture properties of the HAZ are also studied using simulated HAZ specimens subjected to PWHT (post-weld heat treatment). The effect of W on the creep rupture strength of the welded joints is examined.

Creep rupture tests of GTA (TIG) welded joints are conducted. The longest creep rupture time is around 20 000 hours. In the creep rupture tests, the welded joints rupture in the base metal at higher applied stresses, rupturing in the low-ductility fine-grained HAZ adjacent to the base metal at lower applied stresses.

When the welded joints rupture in the base metal, their creep rupture strength is as high as that of the base metal. When the welded joints rupture in the HAZ, however, their creep rupture strength is lower than that of the base metal. The cracking which occurs in the HAZ is TYPE IV cracking which tends to affect the welded joints of ferritic heat-resistant steel. TYPE IV cracking is the type which occurs in the fine-grained HAZ at a lower stress than the creep rupture strength of the base metal without being associated with any heavy deformation.

In the creep rupture tests, the simulated HAZ specimens heated to a temperature around Ac1 and Ac3 give a lower creep rupture strength than that of the base metal. The simulated HAZ specimens heated to the Ac3 temperature give the lowest creep rupture strength.

A comparison of the creep rupture strengths of welded joints produced from 9Cr-Mo-W steel and 9Cr-1 Mo-Nb-V (mod. 9Cr-Mo) steel suggests that W improves the creep rupture strength of both welded joints and base metal.     

高强钢摩擦焊接头感应加热区宽度窄化技术

针对高强钢摩擦焊接头焊后正火感应热处理加热区过宽产生的焊接接头软化失效问题，为窄化感应加热区宽度作了磁轭式感应器；采用红外热成像技术实时检测高强钢钻杆摩擦焊头焊后正火感应热处理过程的温度分布，评定了该感应器窄化感应加热区的效果。     

超细晶粒钢焊接HAZ晶粒长大规律分析

根据传统金属学和焊接冶金学理论，对800MPa和400MPa两个强度级别新一代钢铁材料进行焊接热模拟试验，分析了焊接HAZ晶粒长大规律。结果表明，随着峰值温度和‰的逐渐增大，新一代钢铁材料焊接HAZ的奥氏体晶粒都存在严重的长大倾向，且400MPa级比800MPa级的HAZ奥氏体晶粒长大更为严重。     

Pass-by-pass stress evolution in multipass welds

In multipass welding, each successive thermal cycle will introduce local melting, solid state phase transformations, grain growth, grain refinement, recrystallisation and recovery, all of which lead to a complicated stress state. Most stress measurements performed on multipass welded components represent the final residual stress state. Information concerning stress evolution on a pass-by-pass basis is difficult to find. In this investigation, six pass welds were made on high strength quenched and tempered steel sections, and depth resolved strain measurements in two orthogonal directions were carried out after each weld pass using energy dispersive synchrotron X-ray diffraction. The residual stresses were calculated using biaxial Hooke’s law. A thermal–metallurgical–mechanical welding model was constructed and validated with temperature and pass-by-pass stress measurements, which improves the reliability of the model. Cross-sectional stress distributions are presented after each pass, revealing the weld stress development in multipass welds.