铁素体/奥氏体异种钢接头蠕变断裂研究

为了改善铁素体钢与奥氏体钢之间蠕变强度差别太大的问题,在它们之间接入一段蠕变强度介于之间的过渡段,两条焊缝再选择两种不同蠕变强度的焊条分别焊接,结果可使铁素体/奥氏体异种钢接头的蠕变断裂强度达到铁素体同种钢接头的水平,试验结果进一步证明材料之间蠕变强度不匹配是异种钢接头高温运行过早失效的主要原因。     

12X18H12T与TP347H异神钢焊缝显微组织分析

对末级过热器材质为12X18H12T与TP347H异种钢焊接工艺试验进行研究.通过焊缝外观成型及显微组织分析、扫描电镜、EDS能谱以及奥氏体钢的晶间腐蚀等试验研究,认定两种工艺下的对接环焊缝焊接接头均合格;采用钨极氩弧焊打底(焊丝H1Cr18Ni9Ti)、A132焊条填充盖面的焊接工艺所焊接头性能优于采用钨极氩弧焊打底...     

无铬8号钢用焊接材料的研制

无铬8号钢是立足于我国资源而研制成功的一种高压锅炉过热器管用钢。为了促进无铬8号钢的应用,进行了研制供该钢焊接用的焊条和焊丝的工作。目前研制成功的焊条(或焊丝),与相同工作温度和工作压力下用的热317焊条(焊12Cr1MoV钢)和69新1焊条(焊F11钢)相比,由于它采用了我国富产的硅和稀土等元素来代替铬和镍等元素,不仅节约贵重合金元素,而且高温性能达到了使用的要求。此外,经有关焊接师傅多次施焊,对其焊接工艺性能表示满意。目前,一般的焊条厂均能生产这种焊条。     

316L奥氏体不锈钢厚板焊接工艺及接头性能研究

根据316L奥氏体不锈钢的焊接性,制定了316L厚板的焊接工艺,采用钨极氩弧焊和焊条电弧焊的组合焊接工艺对316L厚板进行了焊接,并对焊接接头进行了力学性能、金相检测和晶间腐蚀试验。结果表明,所获得的焊接接头无缺陷,力学性能合格,焊缝组织为奥氏体和少量δ铁素体,焊接接头无晶间腐蚀倾向。焊接工艺合理,满足316L奥氏体不锈钢厚板焊接生产要求。     

SA-213T91管子与奥氏体不锈钢承载附件焊接的焊材选择

为研究SA-213T91管子与不锈钢承载附件是否可采用AWS E9015-B9焊材,本文采用手工氩弧焊+焊条电弧焊的方法对SA-387Gr91+06Cr25Ni20异种钢进行焊接。对焊接接头进行RT检测、室温力学性能检测和金相显微组织分析。从焊接工艺评定和模拟件焊接试验的角度认为,SA-213T91小口径管子与承受载荷的奥氏体不锈钢附件之间焊接,可以选用合金钢焊材AWS E9015-B9。     

使用铁基奥氏体钢焊条对耐热珠光体钢大型铸件的焊补

在焊补耐热珠光体钢电站设备大型铸件缺陷时,为避免焊接裂纹和改善补焊区性能,通常采用与基材相同类型的焊条,焊前进行予热焊后进行650—720℃的高温热处理。但这种工艺措施十分复杂,并且往往导致经过加工的高精度电站设备铸件变形过大,超出这些铸件装配时的允许要求。本文在分析补焊高精度耐热珠光体钢铸件困难、奥氏体与非奥氏体钢焊接接头特性以及我国电站设备运行条件的基础上,利用铁基奥氏体钢焊条对ZG20CrMOV钢进行了焊接试验,并对全国10多个电站汽轮机的汽缸和主汽阀等大型铸件的缺陷,采取千斤顶增大刚性控制变形和焊后不进行热处理等措施进行了焊补,焊后变形和焊补区的质量均达到理想要求,并经长达10万小时以上的高温高压下实际工作的考验,检查证明焊补区的质量一般仍然良好为电站设备铸件精加工后发现的缺陷焊补,尤其为电站现场补焊提供了一种工艺简便,劳动强度低,修理周期短,容易控制变形和质量可靠的方法。     

12%Cr钢与珠光体耐热钢焊接中的异常现象及其在生产中应用

本文介绍焊接12%Cr钢(F11)和珠光体耐热钢时发现的一种异常现象,即用低匹配焊条焊接时容易产生F11侧焊接热影响区裂缝,用高匹配焊条焊接时不容易产生F11侧热影响区裂缝。利用这种异常现象,选用高匹配焊条,成功地焊接了近万个异种钢焊接接头,消除了裂缝,取得了很好的效果,还利用了这种异常现象预见了某锅炉中的异种钢焊接裂缝,避免了一场重大运行事故。研究指出,氢在焊接接头中分布是不均匀的,焊接材料对氢的分布影响较大,采用低匹配焊条焊接易淬硬钢,会在HAZ形成“富氢带”,容易产生冷裂缝。首先用探针测氢法测得焊接接头不同区域的含氢量,证实“富氢带”的存在。最后指出“富氢带”不仅和焊接冷裂缝有关,而且还和焊接接头运行裂缝有一定的关系。     

新型Ni102B焊条的研制

论述了新型Ni102B镍基焊条的研制、焊接工艺试验及在高强钢焊接的生产应用。     

400吨/时汽包预埋件异种钢焊接接头性能研究

400吨/时锅炉汽包.材料为BHW35,厚度80毫米。内部装置预埋件焊接,制造中选用奥氏体焊条冷焊是可行的,但要遵守一定的工艺规程。主要是选用Avesta P5 φ4毫米焊条,电流≤160安,双道焊。要经受长期运行考验,似应选用碳钢焊条为宜,且有降低预热温度的可能性。     

威海工程再热器交叉管焊接裂纹问题研究

本文根据威海工程再热器交叉管产品生产过程中出现的角焊缝焊接裂纹,分析了裂纹产生的原因,找到了解决问题的办法,并对同类奥氏体不锈钢焊条的抗裂性进行了评估.     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

Heat of vaporization of mixtures

General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996