P91钢焊接接头性能及其存在问题的讨论

介绍了P91钢及其焊接接头性能，重点讨论了焊缝韧性和接头蠕变断裂强度等问题，提出改善它们的建议和可以开展的研究工作。     

T91／P91钢的性能分析及焊接工艺

金属材料在火力发电厂的重要性是不言而喻的,它直接关系到机组的使用寿命和安全经济运行。介绍了T91／P91钢的化学成分和主要物理性能,分析了T91／P91钢的力学性能和抗氧化腐蚀性能,给出了T91／P91钢的焊接工艺和方法,指出了需要进一步研究的问题。     

T91/P91钢现场焊接质量控制

分析了T91/P91钢的可焊接性,介绍了该种钢的焊接和预热、热处理的参数及注意事项,并对现场焊接质量监控的要点加以介绍,提出了一些需要注意的问题。     

高温再热器管异种钢焊接接头失效分析

针对某厂#2高温再热器TP304H G102接头断裂失效的情况,进行了化学成分分析、断口分析、金相检验和金属磁记忆检验,发现该焊接接头在G102侧焊缝处存在约0.01mm增碳层。分析认为,此次焊接接头失效的主要原因是由于该接头处存在应力集中,加速了碳迁移,从而造成了该接头提前出现蠕变损伤断裂。     

TIG熔修提高焊接接头疲劳性能及低温性能研究

本文以普通低合金钢角焊缝为例，研究了TIG熔修对焊接接头性能的影响，研究表明TIG熔修可较大程度地提高接头疲劳强度及低温性能，改善了接头的材质性能。熔修效果取决于熔修规范。TIG熔相等为提高焊接接头疲劳寿命。以及焊缝裂纹补焊后的使用寿命提供了一种途径。TIG熔修工艺适用于水轮机转轮和低温下工件的重要大型水式构件等制造和裂纹处理。     

十字型焊接接头疲劳强度的计算机模拟

利用Monte-carlo方法，对十字型焊接接头的疲劳强度断裂行为进行了计算机模拟，在焊接接头几何尺寸、初始缺陷及裂纹形状的统计分析、断裂韧性及da/dn测试、应力参数分析及裂纹应力强度因子计算的基础上，利用计算机模拟的方法得到了十字型焊接接头的P—S—N曲线。     

异种钢焊接性的研究现状和进展

从焊缝金属、熔合区的组织特征、断口形态、碳纤移、氢行为、应力应变状态和焊后热处理等几个方面，对国内外在异种钢焊接性方面的研究成果进行了综述。     

300MW电动／发电机定子线圈接头的焊接

本文介绍了银铜焊机的特点，并重点总结了电动、发电机定子线圈接头的焊接工艺、检查方法。     

整体卷制巨型压力钢管焊接接头性能评定和残余应力测试

文章对李家峡水电站引水压力钢管整体卷制焊接接头进行了机械性能试验，金相分析和残余应力测试，评定和测试的结果表明，其焊接接头质量均达到规范要求，残余应力的峰值得以下降。     

WDB620钢焊接性试验及焊接工艺评定

国产WDB620钢是610MPa级低焊接裂纹敏感性高强度钢,为了将该钢种应用到三板溪水电站的水轮机蜗壳制造中,对WDB620钢进行了焊接试验,并与日本NKK公司生产的NK—HITEN610U2钢进行了性能对比。结果认为,WDB620钢在板厚≤36mm范围内的焊接性能是良好的,与日本NK-HITEN610U2钢的焊接性能比较接近,WDB620钢的力学性能和焊接性能完全满足设计要求,可以替代日本NK—HITEN610U2钢。     

沉降缝部位压力钢管相对变位的危害及应对办法探讨

阐述了压力钢管在沉降缝部位产生相对变位及其危害性,并提出了利用机组进水阀下游侧的伸缩节来消化吸收此种变位的具体技术措施。     

热处理工艺对14Cr1MoR钢K_(IC)~J和da/dN的影响

分析了不同热处理工艺对14Cr1MoR铜断裂韧度K_(IC)~J和亚临界扩展速率da/dN的影响。结果表明：经730℃回火后14Cr1MoR钢的断裂韧度K_(IC)~J有较明显的提高,裂纹扩展速率da/dN则无明显变化。     

The effect of white or grey PVC pipe and its joint solvents (primer and cement) on odour problems in drinking water distribution systems.

A study of the production of odour-causing compounds was conducted from the leaching of polyvinylchloride (PVC) pipe and its joints, primer and cement, into drinking water distribution systems. Flavour Profile Analysis (FPA), closed-loop stripping analysis--gas chromatography/mass spectrometry (CLSA-GC/MS) and sensory-GC analysis of white or grey PVC alone found no odour-causing compounds produced during the leaching experiments. FPA analysis of the PVC's primer and cement leached alone and/or when applied to grey or white PVC pipes produced a glue/varnish odour. A sweet/phenolic odour replaced the glue/varnish odour after the leached media were diluted with Milli-Q water to threshold odour intensity. Three compounds were responsible for the sweet/phenolic odour and were observed by sensoryGC analysis. The leaching study of the PVC pipe with its joint solvents (primer and cement) concluded that the original solvent compounds, and their reaction products that formed during the bonding process on the PVC pipe, were a primary source of the glue/varnish odour. The original compounds of the PVC primer and cement were not detected by CLSA-GC/MS, due to their high volatility during the CLSA extraction method and/or these compounds appeared in a solvent peak of the GC/MS analysis. However, the original primer and cement chemicals (acetone, tetrahydrofuran, methyl ethyl ketone, and cyclohexanone) had a glue/varnish odour. A total of nine odorous GC peaks were produced as reaction products from leaching of primer in water and white or grey PVC pipe with primer and cement, and white or grey PVC with primer only. None of these compounds were among the chemical ingredients in the original primer or cement. Four GC peaks with a sweet/phenolic odour were present due to the reaction products of the cement leached with white or grey PVC. None of these compounds were positively identified.     

深圳水库二期电站及泄洪闸外观提升工程钢结构屋檐的设计探讨

深圳水库二期电站始建于20世纪80年代,经过近30年的运行,主副厂房及防洪仓库外观较为陈旧,且破损严重,已经严重影响了深圳水库的整体景观要求。本文针对建筑物各种现状屋檐结构的特点,在不改变原有受力的情况下,给出了相应的设计方案,以满足工程的景观要求。在现场制作及安装过程中,结合现场的实际情况及施工经验,又对原设计进行不断的优化改进,通过减轻钢屋架自重、加强结构稳定、完善防锈设计等方法,得出了更合理的设计方案,使其结构更加安全可靠,同时也降低了现场施工的难度,能更好的与现状屋顶结合起来。