L450/316L不锈钢复合钢管对焊缝焊接接头组织性能研究

对壁厚(10+2)mm的L450/316L复合管进行了对焊试验,打底焊及过渡焊采用管内外充氩保护的GTAW焊,填充及盖面焊采用手工电弧焊,并对其焊接接头进行拉伸、刻槽锤断、弯曲、冲击、晶间腐蚀试验评价对焊焊缝的性能,采用光学、扫描电镜(SEM)及能谱分析(EDS)对焊接接头的冲击断口、显微组织及合金元素的进行扩散分析。试验结果表明:接头力学性能良好,耐晶间腐蚀性能较好;焊缝不锈钢层主要有奥氏体、铁素体组成;过渡层组织较细小,可以防止不锈钢层金属中合金元素被扩散层稀释;扩散层组织主要为马氏体、少量的残余奥氏体;合金钢层组织为先共析铁素体、针状铁素体、粒状贝氏体和及少量珠光体。     

固定管板分析设计软件的开发

以JB4732标准附录Ⅰ为基本依据,开发了管板延长部分法兰、管板与壳体法兰贴面焊、平齐焊(或浅嵌入焊)和不带法兰四种结构固定管板设计的计算软件,许用应力可按GB150选取(常规设计),也可JB4732选取(分析设计),并给出计算实例。     

固溶处理对316L扩散焊接头力学性能和组织的影响

对316L材料扩散焊接头进行固溶处理。采用拉伸试验和硬度测试方法,研究固溶处理对316L扩散焊接头力学性能和硬度的影响。采用金相、EDS和XRD等微观方法,观察扩散焊接头在固溶处理前后的金相组织、元素扩散和相组成情况。     

内外施焊接管焊接接头应力的有限元分析

应用Ansys有限元应力分析软件,根据钢制化工容器结构设计规定(HG20583-1998),分别建立了内部施焊和外部施焊的内伸入式接管与壳体间焊接接头的模型,分析了焊接接头处应力分布情况,并对焊接接头处的应力进行了对比。结果表明,内部施焊的整个焊缝X方向的应力平均值大于外部施焊焊缝;外部施焊的整个焊缝Y方向应力水平略大于内部施焊焊缝;内部施焊焊缝等效应力的应力值小,但其高应力区域范围较大。     

α-Al_2O_3陶瓷与金属镍的真空扩散焊

为研究α-Al2O3陶瓷和金属镍之间的扩散焊接,以α-Al2O3陶瓷和高纯金属镍为母材,通过真空扩散焊的方法,考察焊接温度、压力及保温时间对焊接效果的影响。采用电子万能试验机测试工件的焊接强度,用扫描电镜(SEM)观察陶瓷与金属界面的显微结构,用能谱仪(EDS)研究焊接面的扩散情况。结果表明:用Mo-Mn法将陶瓷表面金属化,在θ=1 164℃、p=7.5 MPa、t=30 min的实验焊接条件下,具有较强的扩散能力,金属镍向α-Al2O3陶瓷一侧扩散渗透,实现了α-Al2O3陶瓷与金属镍的连接。     

热焊工艺对2.25Cr1Mo钢焊接构件疲劳寿命影响

对2.25Cr1Mo试板分别在室温下进行焊接焊后自然冷却以及加热到600,700,800℃进行焊接焊后保温缓冷(即热焊工艺),采用小盲孔法测量焊接残余应力,以此为基础分析了热焊工艺对其疲劳寿命的影响。试验结果表明,采用热焊工艺进行焊接可以有效地提高焊接试件的疲劳寿命,并且加热温度越高,焊接试件的疲劳寿命越长。     

扩散焊吸液芯结构对热管传热性能的影响

利用扩散焊分层实体制造技术对蚀刻紫铜薄片进行焊接,完成吸液芯结构(微通道)的制造以及平板热管整体结构的装配。通过系统研究分析了槽道宽度、加热功率以及冷却方式对热管性能的影响。结果表明,该方法能较好地实现热管吸液芯结构以及整体结构的制造;试验过程中槽道宽度为0.4 mm的热管性能最优,在加热功率为40 W、水平放置、加热过程伴随风冷的试验条件下,其最大当量热导率能达2552.2 W·m-1·K-1,为紫铜的6.7倍。采用扩散焊分层实体制造的方法可以在槽道中形成很多小槽道,有利于液体工质的回流,从而提高热管的导热性能。     

水泥厂实用机修技术(四十五)第十三讲零件的手工电弧焊修理(四)

13.4.3铸铁焊补要点 水泥厂中,铸铁补焊常用于灰铸铁的缺陷和损坏.铸铁的可焊性差,手工电弧补焊需要采取特殊工艺措施.铸铁补焊方法有冷焊、半热焊、热焊和不预热焊几种(见表13-8),不同的方法需要选用的焊条和施焊要领也有所不同.如果选择焊条不当和不注意采取相应的焊接措施,就极易产生白口、裂纹等焊接缺陷.     

陶瓷/金属扩散焊连接技术的研究现状及应用

陶瓷具有优异的综合性能,在许多领域都有着广泛的应用,但其存在加工性能差的弱点,通常需与金属相组成复合结构。实现陶瓷与金属之间的稳固连接是推进陶瓷复合材料应用的关键点,扩散连接被认为是陶瓷/金属连接中较为适合的方法。笔者对近年来国内外陶瓷/金属扩散连接技术领域的研究现状进行了综述,并指出了扩散焊连接将成为未来陶瓷/金属连接的发展方向。     

粘接代替电焊在低温室中的应用

我厂低温室的铝铁皮(0.5毫米厚),76平方米的大面积连接密封都不能用锡焊,特则是墙壁顶棚,要求在-60℃的温度下长期使用,更不能用锡焊,因此影响了工程进度.经过试验可用粘接代替电焊,保证了新工房工程的顺利进行.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。