汽轮机滑动轴承轴瓦表面塑性变形的规范选择

本文研究了在使用汽轮机过程中滑动轴承巴氏合金轴瓦的破坏原因,以及表面塑性变形对轴瓦磨擦技术性能的影响。根据巴氏合金轴瓦表面层的质量参数,选择了表面塑性加工的规范。     

百万核电汽轮机轴瓦制造中的问题分析

针对百万核电汽轮机轴瓦浇注巴氏合金后在无损探伤环节中暴露出的问题进行分析,认为巴氏合金浇注环节的控制是影响轴瓦最终质量的关键因素,通过对合金浇注各个环节的深入分析,发现浇注工艺存在一些问题,以及一些细节未能有效处理,对此提出了改进措施。     

轴承巴氏合金补焊试验研究

介绍了采用氧一乙炔补焊方法修复铸造轴承巴氏合金的工艺试验,通过试验数据和使用情况论证了补焊修复轴承巴氏合金的可行性.     

巴氏合金轴套冷装工艺

基于某柴油机巴氏合金轴套对冷装工艺适应性的要求，对其进行液氮冷却试验、低温箱冷却试验，检测结合强度、硬度、金相组织等性能变化情况。试验表明：巴氏合金轴套不适宜采用液氮冷装工艺，会造成巴氏合金与钢背脱离，造成失效；巴氏合金轴套可采用低温箱冷装工艺，适宜的冷装温度为70~80 ℃。     

汽轮机巴氏合金轴瓦缺陷焊接修复的可行性

本文简述了巴氏合金的工作性能、要求。通过对用氧乙炔气焊修补巴氏合金轴瓦工作及试验、检测的总结,提出用焊补修复有缺陷的巴氏合金轴瓦可以保证轴瓦的工作性能不会下降,同时可以节约贵重金属。还介绍了具体的焊补工艺经验。     

锡基巴氏合金的金相组织和铸造缺陷

众所周知,巴氏合金通常用铸造的方法将其浇铸在低碳钢钢背上,制成钢背—巴氏合金双金属轴瓦。巴氏合金由于其浇铸温度较低,加工工艺比较简单,合金的表面性能优良,故在很长的一段时期内成为发动机的主要轴瓦材料之一。但是,随着发动机向高速、重载的方向发展,巴氏合金作为轴瓦材料使用时,明显暴露出承载能力较低、疲劳强度不足;并随着工作温度的升高;机械性能急剧下降的弱点,故其应用范围逐渐缩小并受到一定的限制。然而,巴氏合金与其它轴瓦合金相比较,有良好的顺应性和抗咬合性,这种优点特别对运转初期的磨合十分有利,巴氏合金的嵌藏性好,故在轴颈表面不易出现划痕。它与润滑油的亲和力强,亲油性好,所以能很快达到液体润滑,锡和铅常温下可形成再结晶而软化,因此在摩擦面上由于重复载荷作用而发生的硬化,可很快软化复原。因而,直至今日,巴氏合金轴瓦在汽油机、低速船用柴油机以及内燃机车上仍有一定的应用。另外,在蒸汽透平机、透平泵、压缩机、发电机、电动机、球磨机、齿轮箱上,巴氏合金轴瓦的应用仍十分广泛。本文扼要介绍我国应用较广泛的锡基巴氏合金的金相组织和铸造缺陷,仅供参考。     

轴承巴氏合金的碎裂机理及润滑油的监测

分析了滑动轴承巴氏合金轴瓦在固体、液体和气体作用下引起碎裂的机理及其润滑油中的杂质循征。提出了轴承巴氏合金碎裂的诊断规则。     

铅基轴承合金的强化及应用

0 前言 巴氏合金是传统的轴承合金材料,广泛地用于制造各种轴瓦,但最大的缺点是硬度和疲劳强度低,当温度超过100℃时,硬度和强度急剧下降,当温度达到150 ℃时,其硬度和疲劳强度大约是常温时的1/3,以铅基巴氏合金ZChPbsb10—6为例,轴承最大允许负荷（98×10~5 ～117.6×10~5）Pa,许用圆周速度为12m/s。近年来发动机朝着大马力高速度高负荷方向发展,对轴承的比压力也随之提高,如EQ140型发动机连杆瓦最大负荷达～182.6×10~5Pa,PV值在1960 ×10~5Pa·m/s以上,大大超过了巴氏合金使用限度。然而巴氏合金具有良好的嵌藏性,膨胀系数小等优点。因此,铅基合金仍有市场、如中速37Д型柴油机,N(?)5型柴油机的部分轴瓦,和国内中等负荷的汽车轴瓦。国内外广泛地用铅基代替锡基巴氏合金,目前国内生产铅基巴氏合金厂有十多家,铅基巴氏合金,其极限强度与弹性系数的比值却大于锡基轴承合金,因此,其疲劳强度略高于锡基轴承合金。疲劳强度作为轴承     

滑动轴承等巴氏合金/钢复合层质量超声波检测与评定

关于巴氏合金/钢复合层结合质量的检测,国内尚无一定分级标准,探伤工艺各种各样,基本上还处于定性阶段。本文根据国外有关工艺资料和标准,结合国内生产实际经验,对巴氏合金/钢复合层的超声波检测进行介绍。     

内燃机曲轴轴承减摩材料的发展动态

现代内燃机曲轴轴承广泛采用的减摩材料有三类:锡基或铅基巴氏合金、铜基合金、铝基合金。 巴氏合金是最早的轴承减摩材料,具有极佳的表面性能,可以配用不经硬化的曲轴。然而,在现代内燃机中,由于其疲劳强度太低,高温下硬度和强度     

轴瓦乌金损坏的焊补

汽轮机轴承间隙过大、乌金局部脱落、龟裂、裂纹,砂眼、气孔、脱胎等缺陷,在检修中经常遇到。如果重新浇铸,不但造成资材浪费,还可能导致瓦胎变形。因此,可对乌金局部损坏的轴瓦进行补焊。1.轴承乌金局部磨损量大的补焊工艺1.1 选用同种型号和成份的优质乌金制成直径7mm,长约300mm的焊条。制作过程中,熔化乌金的温度不宜过高。1.2 把需要补焊的轴瓦乌金表面均匀地刮     

300MW汽轮机油系统常见问题浅析

对油系统运行中经常出现的清洁度不好、烧瓦、油压低等问题进行了分析，提出解决办法。     

氟塑瓦在卧式轴承中的应用与维护

陕西省石头河水电站 4#卧式水轮发电机组采用金属弹性氟塑料瓦代替原巴氏合金推力瓦、导轴瓦取得了令人满意的效果 ,本文对该瓦的结构特点、应用前景作了介绍 ,亦为老水电站机组降低运行温度 ,延长大修周期 ,提高机组效率等方面提供了借鉴经验     

轴承巴氏合金磨损试验的优化设计

在MG-2000摩擦磨损试验机上采用改进的环环试验方法进行巴氏合金与轴颈材料对磨试验,通过对试样优化设计,确定了试样的最佳尺寸和形状,改进了试验方法。试验结果与工程实际情况相吻合,该试验方法和所确定的试样形式和尺寸适合用于汽轮机大型滑动轴承边界润滑状态下的巴氏合金磨损试验。     

Ash-forming elements in four Scandinavian wood species. Part 1: Summer harvest

Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden.     

NEXT GENERATION ENGINEERED MATERIALS FOR ULTRA SUPERCRITICAL STEAM TURBINES

正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%.     

Contents in Volume 23,2014

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Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。