焊条药皮含水量的测定

对焊条药皮含水量的测定具有较大技术价值。试验证明,焊条药皮的含水量与熔敷金属中的扩散氢含量有一定的对应关系。如果控制了药皮的含水量,也就直接地控制了扩散氢含量。再者,通过对药皮含水量的测定,还可对确定焊条的烘干条件、存放时的温度、湿度要求提出合理的依据。在制定焊条国标过程中,为确定焙烧-吸     

低尘型交直流两用碱性焊条的研制

分析了多种国内外碱性焊条药皮渣系,设计了CaO-CaF2-BaO-TiO2-SiO2渣系.用均匀设计的思想方法和计算机软件安排试验.进行了药皮组分对交直流两用焊条工艺性能和发尘量影响的研究,并研制成功环保型交直流两用碱性焊条,其各项指标均达到预期目标:熔敷金属扩散氢(甘油法)含量为2.9 mL/1OO g;发尘量为10...     

高强焊条药皮碱度对韧性与扩散氢的影响

通过使用钛硼微合金化以获得韧性组织焊缝、提高焊条药皮碱度以净化焊缝等手段,可使屈服强度级别为785MPa的手工焊条熔敷金属-50℃冲击吸收功AKV平均值超过80J.但焊条药皮碱度过高时,AKV(-50℃)值没有明显增加,而且对降低熔敷金属扩散氢不利.采用对焊条药皮原材料进行分类高温去水处理,对成品焊条多次烘干吸湿烘干处理后,反复测定.结果表明,当焊条药皮碱度在2.2～2.4之间时,熔敷金属可同时具有高屈服强度、高低温冲击吸收功及超低扩散氢.     

E5015药皮原料粒径对其熔敷金属扩散氢含量的影响

为了研究药皮原料粒径对E5015焊条熔敷金属扩散氢含量的影响,特选取氟石和大理石作为研究对象。对氟石和大理石粉料进行时间梯度球磨、购买纳米大理石粉料、用SEM对粒径观察、对氟石系列和大理石系列进行焊条制备和测试。试验结果表明:氟石原料经过时间梯度球磨后粒径明显减小,焊后熔敷金属扩散氢含量明显降低。随着大理石粒径的减小,焊条熔敷金属扩散氢含量逐渐下降,但随着纳米大理石相对含量的增加,扩散氢含量有逐步升高的趋势。总之,原料粒径的细化对焊条熔敷金属扩散氢含量的减小有明显作用。     

纳米大理石对D600R堆焊焊条性能的影响

用粒径70～90nm大理石取代堆焊焊条D600R药皮中的微米大理石,制成纳米大理石焊条.利用汉诺威电弧质量分析仪对焊接过程中的电流电压和短路时间进行测试,获得微米大理石焊条和纳米大理石焊条的燃弧特征;通过焊接工艺试验、测氢试验、熔化温度测试、硬度试验、耐磨试验和微观分析,分别对两种焊条的工艺性能和力学性能进行分析.结果表明,用纳米大理石替代微米大理石可降低焊条药皮的熔化温度和堆焊层金属中的扩散氢含量;提高焊条的熔敷效率;降低焊条短路电压、短路电流概率密度和,在短路时间t12.05ms时间段内缩短累计短路时间;改善焊条操作性能;提高堆焊层金属硬度和耐磨性.     

纳米稀土氧化物对铁粉焊条焊缝低温冲击韧度的影响

在碱性铁粉焊条药皮中添加不同量的纳米稀土氧化物粉体.对焊缝进行扩散氢含量、低温冲击及化学成分的测试和分析.结果表明:适量的纳米稀土氧化物粉体可有效降低熔敷金属中扩散氢及硫、磷的含量,并能显著提高焊缝金属的低温冲击韧度.     

14MnVTiRE钢配套焊条的改进及性能与组织

对14MnVTiRE钢配套焊条进行了改进,并进行了焊缝性能与组织试验.研究表明,通过调整焊条药皮成分,使药皮含水量及扩散氢较低,使其焊接接头的韧性得到明显改善.     

酸性焊条药皮主要组分对熔化温度及其区间的影响

通过对酸性焊条药皮熔化温度的测定,研究了金红石、大理石、白泥等三种主要组分对酸性焊条药皮熔化温度和熔化温度区间的影响规律。该规律对于研究酸性焊条药皮组分对焊条药皮物理性能和工艺性能的影响有实际参考价值。     

低碳钢水下焊焊条的研究

前言水下涂药焊条湿法焊接,虽然经过人们多方面的改进,但至今,焊条的工艺性能和接头的机械性能还是比较差。从国内外情况来看,接头的抗拉强度和塑性,一般只有陆地上焊接时的80％和50％左右。根据水下特殊环境对焊条提出的各项要求,通过焊条药皮配方的调整,研制了两种新型的水下焊焊条。对其工艺性能,特别是电弧稳定性以及接头的扩散氢含量、抗拉强度、冷     

基于均匀设计方法研究不锈钢焊条的药皮温升

为探索从药皮配方改善不锈钢焊条尾部发红开裂的技术路线，基于均匀设计计算机软件制作、研究了28个不锈钢焊条小样。试验中选定12种药皮辅料作为自变量，并把每个自变量分成7个水平；把焊接过程中焊条的药皮温升作为指标，并用热电偶和X—Y记录仪测定。通过数理统计给出了自变量及其交互作用对应于指标的数学模型和趋势图。它们揭示出多种药皮辅料对药皮温升影响的内在规律：①萤石或长石含量增加时（其它组分含量固定在中值），焊条药皮的温升减弱。②有些药皮辅料如云母、铁砂、白泥、大理石和金红石，对焊条药皮温升的影响呈交互作用形式。     

Determining diffusible hydrogen amounts using the mercury method

This article presents detailed characteristics of a procedure for quantitative determination of diffusible hydrogen using the mercury method compared with other research methods and current know-how concerning the question considered. Classification of hydrogen appearing in welded joints, and methods of quantitative determination of diffusible hydrogen in weld deposits, with particular attention paid to the mercury method as the basic method, were all discussed. Analytical dependencies making possible conversion of other methods' indicators to match results obtained with the mercury method were also listed. A mercury method test station and the procedure for drawing of test pieces, forming of experimental stand welds, carrying out of experiments, analysis of results and drawing up of test reports were all described. The use of calibrated alternative methods was emphasized.     

埋弧焊焊缝组织与扩散氢的关系

综述了埋弧焊焊缝组织与扩散氢的关系。结果表明,硅酸盐粘合剂中的水分是EM12K焊剂扩散氢的主要来源。镀铜层和表面润滑剂是ER100-S1焊丝中两个主要的氢源。埋弧焊电弧中会发生两个与焊剂中氟化物有关的冶金反应。建立了焊缝组织与扩散氢的关系,其要点是氢在焊缝中的扩散方向和聚集部位,并影响氢致裂纹的发生。所谓低氢化工艺是一种使焊缝中残留的氢很少,不足以引发氢致裂纹的综合工艺措施。提出了低氢工艺"合于使用"原则。     

钛对药芯焊丝熔敷金属扩散氢的影响

通过添加不同量的钛铁到药芯焊丝中,并在不同保护气焊接的条件下,研究其对熔敷金属扩散氢的逸出和含量的影响.结果表明,保护气体氧化性的增加可以降低熔敷金属扩散氢,而保护气还原性的增加,则熔敷金属扩散氢含量也会相应增加;在药芯焊丝中加入一定量的钛铁,一方面TiO,Ti(C,N)颗粒会在熔敷金属中形成的不可逆氢陷阱,对氢产生捕获作用,可以降低熔敷金属扩散氢;同时,加入的钛铁会提高电弧气氛的还原性,这样会增加熔敷金属的扩散氢,所以适量的添加钛铁,使钛铁对焊接气氛的氧化性的影响和形成不可逆氢陷阱的作用之间合理的结合,能达到理想的降氢效果.

Abstract：

The effects of Ti content on diffusible hydrogen escape characteristic of deposited metal of flux cored wire were investigated by adding different quantities of Ti-Fe and in different protecting gas conditions. The results show that the oxidative susceptibility of protecting gas can decrease the diffusible hydrogen of deposited metal, and the grains of Ti and Ti(C,N) which exhibit irreversible hydrogen traps can also decrease the diffusible hydrogen of deposited metal. The rational adding Ti-Fe, which harmonized the oxidative susceptibility of welding atmosphere and formed the irreversible hydrogen traps, could obviously decrease the diffusible hydrogen of deposited metal.     

Diffusible and residual hydrogen in amorphous Ni(Cu)–Zr–H alloys

The partition of hydrogen into diffusible and residual parts was realized by pulse NMR spectroscopy, by gas chromatography and by prompt gamma activation analysis (PGAA). The total hydrogen content was determined by the two non-NMR methods and the diffusible (mobile) component by CPMG NMR pulse sequence. Results on amorphous Ni(Cu)–Zr–H systems of different compositions are shown. Partially crystallized samples were also studied as an extension. A method proposed by us directly gives the fractional population of hydrogen atoms in the free (mobile) state on the spin–spin relaxation time scale. On the other hand the least values of the residual hydrogen content correlate surprisingly well with the numbers of filled four Zr-type H-sites calculated by Batalla et al. [NATO ASI Ser. 136 (1985) 203] for 0.21-nm exclusion distance.     

合金钢焊接区显微组织与扩散氢的动态分布关系

运用显微镜下录像测氢法研究了４种不同预处理状态下的国产低合金高强钢焊接区扩散氢动态分布的规律，结合焊接接头不同组织区的硬度及金相分析，发现扩散氢在熔合区及粗晶区与细晶区交蜀处存在局部聚集，扩散氢呈变形正弦曲线分布，研究结果表明，焊接区氢陷井的不均匀分布是造成扩散氢局部聚集的主要原因，这对于工程实践中防止焊接冷裂产生以及进一步分析焊接冷裂纹的形成机理提供了理论依据。     

水下焊条电弧焊扩散氢含量及焊缝组织特征分析

对影响水下焊条电弧焊扩散氢含量的主要因素和焊缝组织进行分析研究.结果表明,电弧周围的水对焊缝增氢的贡献并不大,仅仅使扩散氢含量增加0.4%,扩散氢来源的主体是药皮中的结晶水和防水层材料所携带的H元素,分别使扩散氢含量增加12.1%和21.8%,工件表面的铁锈也是焊缝增氢的一个不容忽视的因素,会使扩散氢含量上升达28.2%.焊缝组织为少量的侧板条铁素体和贝氏体,热影响区(HAZ)则含有大量马氏体组织.其焊接接头的最高硬度一般都超过0.4 GPa,硬度峰值出现在熔合线附近,在焊缝热影响区内会形成典型的焊道下裂纹缺陷.     

重要承载钢结构氢致裂纹影响因素分析

Q390低合金高强钢焊接时存在一定的冷裂倾向.对于具有较大拘束应力状态的Q390钢结构,需研究其熔敷金属氢致裂纹的影响因素,而氢致裂纹是由焊接过程中产生的扩散氢引起,故采用甘油法相对比较和分析了不同焊丝类型、不同环境湿度对Q390钢熔敷金属扩散氢含量的影响.结果表明,相同湿度下,实心焊丝熔敷金属扩散氢含量均明显小于药芯...     

Effect of hydrogen on the fracture behavior of high strength steel during slow strain rate test

The effect of hydrogen on the fracture behavior of the quenched and tempered AISI 4135 steel at 1450 MPa has been investigated by means of slow strain rate tests on smooth and circumferentially-notched round-bar specimens. Hydrogen was introduced into specimens by electrochemical charging and its content was measured by thermal desorption spectrometry (TDS) analysis. Results showed that the steel had high hydrogen embrittlement susceptibility. For both smooth and notched specimens, the fracture mode was changed from microvoid coalescence (MVC) to brittle intergranular (IG) fracture after the introduction of a small amount of diffusible hydrogen. Fracture initiated in the vicinity of the notch root for notched specimens, while it started from around the center in smooth specimens. The fracture stress decreased with increasing diffusible hydrogen content, and the decreasing trend was more prominent for specimens with a higher stress concentration factor. Taking into account the stress-driven hydrogen diffusion and accumulation in the vicinity of the notch root, the local diffusible hydrogen concentration and local fracture stress in notched specimens have been calculated. According to numerical results, the relationship between the local fracture stress and local diffusible hydrogen concentration was independent of stress concentration factor, which could account for the effect of hydrogen on the fracture stress of the steel.     

Investigation on mechanism of reducing diffusible hydrogen in weld using microelements

0IlltroductionRareearthshavethefunctionofreducinghydrogenduringweldingmetallurgy,andhavenotableeflbctonimprovingthecrackingresistanceinweldedjoint.RareelementTealsocangreatlydecreasetheditTusiblehydrogeninweldbead,andimprovethecoldcrackingresistancepropertyinweldedjoint.Inthisthesis,theinfluenceofmicroelementsyttrium(Y)andtclluriunl(Te)ontheditTusiblehydrogeninweldbeadandonthecoldcracldngsusceptibilityofxveldedjointhasbeeninvestigated,andthemechanismofmicroelementshasbeenanalyzed.lTestmethod…