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《机械制造文摘:焊接分册》2016,(1)
阐述了熔敷金属中扩散氢的存在形式、产生、来源及危害。介绍了4种扩散氢检测方法,即甘油法、水银法、气相色谱法和载气热提取法,总结了4种检测方法的优劣,并对4种方法进行了比较,指出了4种方法测定扩散氢的差异。简述了焊接热输入、焊接道数、冷却方式及焊接环境等因素对扩散氢含量的影响。 相似文献
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全国焊接标准化技术委员会于1993年10月在宜昌召开了《熔敷金属中扩散氢测定方法》标准修订审查会,经过代表们认真讨论修改,一致通过了标准报批稿.新标准基本上等效JIS和ISO现行测氢标准.现将主要改变部分介绍如下.(1)新标准除了保留甘油法外,根据国际上测氢发展趋势及我国超低氢焊条发展情况,增加了色谱法和水银法,并且标准中明确规定,当用甘油置换法测定的熔敷金属中的扩散氢含量小于2ml/100g时,必须使用气相色谱法测定. 相似文献
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根据相关标准,扩散氢的测试方法主要有甘油法、水银法、气相色谱法和热置换法四种.其中,甘油法的应用最普遍,使用时间最长,测试成本最低,安全性最好,因此长期在标准中得到应用.但是,甘油法的测试精度较低,特别是超低氢情况下,更是很难满足要求.最新的国家标准已经不推荐使用.在天津大学排液法基础上进行结构优化改进,从而研发了一种新型甘油法扩散氢测试技术.通过与国内通用设备KQ-3型甘油法扩散氢测量装置进行实验对比,测试结果表明,在焊条电弧焊中使用碱性焊条E5015(天津大桥),测量精度比KQ-3型设备高24%~28%,使用CO2气体保护焊时,测量精度高28%,使用氩弧焊时,测量精度高28.7%. 相似文献
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一、前言测定钢铁中,焊缝中的氢量是研究氢致裂纹和氢致脆化的重要内容之一。经过多年的探索,1949年stern首先提出了甘油法测氢,随后便得到了广泛的应用。然而甘油的粘性大、溶氢,故测量误差严重。于是从1952年以后在欧洲陆续采用水银法代替甘油法。并于1971年IIW第二委员会把水银法测氢定为IIW的基本测氢法。但甘油法操作简单,安全性好,故仍被世界上多数国家所采用。许多国家为继续采用 相似文献
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探究了GB/T 3965—2012《熔敷金属中扩散氢测定方法》中载气热提取法收集条件对测定扩散氢含量的影响,并与水银法进行了对比。研究结果表明,样本炉温设定为400℃,A型试块的内部温度大约在51 min时稳定在358℃左右,B型试块内部温度大约在27 min时稳定在391℃左右;载气热提取法电信号曲线收集结束点的电信号及斜率均接近0时获得的结果与水银法具有较好的一致性。 相似文献
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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. 相似文献
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扩散氢是导致高强钢焊接接头产生冷裂纹的主要原因之一,为降低焊条熔敷金属中扩散氢含量,选择和调整药皮组分以降低扩散氢含量,本文通过排液测氢法测定扩散氢,并建立起碱性焊条药皮组分与扩散氢含量之间的数学模型,通过计算机绘制的扩散氢等值线图分析了药皮组分及其相互作用对扩散氢含量影响的规律;提出了预报和控制扩散氢的方法,这对焊条设计具有指导意义。 相似文献
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0IlltroductionRareearthshavethefunctionofreducinghydrogenduringweldingmetallurgy,andhavenotableeflbctonimprovingthecrackingresistanceinweldedjoint.RareelementTealsocangreatlydecreasetheditTusiblehydrogeninweldbead,andimprovethecoldcrackingresistancepropertyinweldedjoint.Inthisthesis,theinfluenceofmicroelementsyttrium(Y)andtclluriunl(Te)ontheditTusiblehydrogeninweldbeadandonthecoldcracldngsusceptibilityofxveldedjointhasbeeninvestigated,andthemechanismofmicroelementshasbeenanalyzed.lTestmethod… 相似文献
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Investigationonmechanismofreducingdiffusiblehydrogeninweldusingmicroelements¥DUZeyu;DINGPingandZHANGWenyue(MaterialsSciencean... 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):408-413
AbstractA systematic study was conducted to examine the effectiveness of pre- and post-heating to bring down the diffusible hydrogen (HD) content in the welds to levels that are unlikely to cause cracking. Specimens for HD measurement were prepared as per ISO standard 3690, and the measurement was carried out using standard mercury method and the newly developed hot extraction technique, which uses a hydrogen sensor. Results show that pre- and post-heating of the weld at lower temperatures are more effective than preheating alone at higher temperatures to bring down the HD content in the welds. Results also indicate that if the HD content of welding consumable is known, it is possible to choose the preheat and post-heat temperatures that will bring down the HD content remaining in the weld to sufficiently low levels so that danger of delayed cracking is minimum. Such information can help to optimise the pre- and post-heating requirements during weld fabrication, resulting in substantial energy savings. 相似文献