高、中压缸法兰紧固螺栓断裂原因及解决措施

嘉兴发电厂 1号 30 0MW机组高、中压内缸GH4 14 5 /SQ材料法兰紧固螺栓发生断裂。引起断裂的原因是 :制造法兰紧固螺栓材料的冶金质量、晶粒度和金相组织有缺陷 ;螺栓材料的疲劳性能不稳定、剩余力学性能劣化、热脆性明显 ;在高温蠕变条件下 ,螺栓材料的塑性性能变差。应加强对螺栓材料的监督措施 ;提高冶炼质量 ;螺栓制造厂在制造该螺栓前 ,应检查螺栓材料是否合乎要求 ;适当降低高、中压缸接合面处定位螺栓的预紧力 ;采取对称换位拆卸法拆卸螺栓 ,拆卸时防止螺栓机械损伤 ;螺栓研磨不得用MoS2 润滑剂 ;装配法兰时对有机械损伤的螺栓表面应打磨光滑。     

哈汽660 MW汽轮机螺栓安装工序

汽轮机汽缸法兰螺栓承担着把合汽缸法兰结合面使其密封的重要作用,适当的紧固力能保障机组运行中汽缸法兰严密不漏汽,使螺栓的使用寿命延长,因此提高汽缸螺栓安装工艺质量极其重要。介绍哈汽660 MW汽轮机螺栓安装工序及安装经验,实践结果表明,减少了汽轮机汽缸螺栓的损坏,降低设备零件投入费用,减少人力投入成本,保证了汽轮发电机组的安全稳定运行。     

紧固力矩下变电构架法兰螺栓原型试验研究与有限元分析

为研究变电构架柱头法兰螺栓在紧固力矩作用下的受力性能,开展原型试验,并采用机械有限元软件SolidWorks对试验模型进行精确分析。将构架法兰螺栓数值仿真结果与试验结果进行验证,结果表明采用SolidWorks仿真可以有效提高变电构架法兰螺栓的计算精度。精确计算螺栓的受力应考虑紧固力矩对法兰螺栓的影响。     

浅析汽缸螺栓的受力及拧紧方法

为保证汽缸法兰的严密性，不仅要求汽缸法兰、螺栓在机组启动带负荷后保证汽缸接合面的严密性，还要求在长期高温、高压下，螺栓因蠕变变长而发生应力松弛后，也能保证其严密性。文章简单介绍了汽缸汽缸和法兰螺栓的材料选用、材质许用应力、螺栓在各种状态下的受力分析以及汽缸螺栓的拧紧方法。     

亚临界600 MW汽轮机组五、六段抽汽超温处理

大唐盘山发电有限公司(盘山电厂)600 Mw汽轮机组低压缸五、六段抽汽温度超过设计值,主要原因为汽轮机低压内缸中分面处的漏汽,以致降低了机组的出力及效率.从法兰螺栓紧力的计算入手,发现低压内缸漏汽为内缸产生明显变形所致.对此,采取了加大汽缸中分面法兰螺栓紧力及加密封键等措施,实施后五段、六段抽汽温度分别比实施前下降了25℃、40℃,达到了预期效果.     

高温镍基螺栓带状组织失效研究

螺栓在火力发电厂中广泛使用于电站设备的汽缸、主汽门、调速汽门以及蒸汽管道法兰等需要紧固连接或密封的部件上。R26螺栓作为典型的高温镍基螺栓，凭借其良好的蠕变强度和持久强度、抗应力松弛和抗氧化能力强等性能，越来越广泛地被用作超临界机组主汽门、调速汽门紧固部件。然而，随着机组运行时间的延长，高温镍基紧固螺栓断裂数量比例偏高，使得该类型螺栓在推广应用方面存在一定的风险。经过对断裂螺栓化学成分检验、金相检验以及力学性能试验研究，结果表明螺栓的显微组织在晶界上存在严重偏析，析出相呈带状分布，是标准不允许的带状组织，并造成螺栓硬度高于标准要求，对设备的安全运行构成隐患。     

用光弹性法测量调速汽门螺栓应力

前言螺栓是电厂中重要的紧固另件之一。它起着使汽缸法兰、阀门、管道法兰等汽密的重要作用;它紧固的好坏直接关系到生产及人身的安全。正由于此,有些电厂在紧固螺栓时认为紧力越大越好;同时在紧固方式上一般都用大锤猛击搬手。由于螺栓位置的不同,用力极为不均,再则人的锤力亦不同,这就使得同一阀门上各个螺栓的紧力相差很大,有的已接近屈服值(1)。这就造成断裂事故相当频繁,尤其是调速汽门的螺栓,断裂的几率比别的大。目前有的电厂在紧固工艺上正在逐步改革原有的方式—如用风动板手等,但这仅仅是使同一法兰上的各螺栓紧力达到较均匀的水平。究竟达多大紧力能使法兰既汽密而螺栓又不断或少     

螺栓轴向应力的超声波测量

一些设备上的关键螺栓;安装或紧固时,人们希望能直接准确地控制螺栓的轴向应力,以保证其工作的可靠性,这点对电力设备尤其具有重要的意义。用超声波技术研制成功了一种可直接测量螺栓轴向应力的螺栓轴向应力仪,该仪器可广泛应用于关键设备的紧固测试,进而精确地控制螺栓轴向应力。对用超声波技术测量螺栓轴向应力的基本原理进行了介绍,并给出了超声波螺栓轴身应力仪应用实例。     

一起GIS母线开裂故障原因分析

针对一起330 kV GIS母线开裂故障,介绍了故障经过及现场检查情况。从GIS母线设备应力计算、伸缩节调节尺寸、故障母线壳体法兰材料检验等方面进行分析,得出此次设备故障原因是设备滑动支撑结构设计不合理,壳体和伸缩节法兰连接的螺栓紧固力矩不均匀,导致壳体法兰圆周方向变形量不同,使法兰局部产生应力集中以及伸缩节选型不当等三方面因素综合作用,引发了母线壳体被拉裂的故障。     

25Cr2MoV高温紧固螺栓断裂原因分析

某电厂汽轮机高压外缸1根紧固连接螺栓发生断裂,采用宏观检测、化学成分分析、显微组织分析、力学性能测试、断口形貌及能谱分析等方法对螺栓断裂原因进行了分析。结果为:该螺栓因加工工艺不当,造成局部区域晶粒粗大,冲击韧性严重不足,最终在承载最大的部位发生了脆性开裂。并提出加强对汽轮机各部位高温紧固螺栓的金属技术监督,严格规范高温紧固螺栓的采购、入库和使用的把关检验等建议。     

超临界汽轮发电机组汽温异常对汽轮机疲劳寿命的影响

采用汽轮机变工况热力计算,利用有限元方法计算某型号600 MW超临界机组汽轮机高中压转子在调峰运行下的主蒸汽温度发生大幅波动时的温度场、应力场,并得到转子应力集中部位的载荷谱,然后对该工况进行转子疲劳寿命分析。提出超临界机组直流锅炉汽温控制的要点,建议该类型机组在启动或调峰过程中加强运行操作培训,提高自动控制系统调节品质,将蒸汽温度、调节级温度以及中压缸进汽温度作为重点控制对象,严格控制温度变化率。     

国产600MW超临界汽轮机组冷态启动热应力有限元分析

本文主要研究利用matlab编制适用于计算各种汽轮机转子的放热系数的程序,然后利用marc有限元软件计算国产600MW超临界汽轮机转子在冷态中压缸启动工况下的温度场和应力场。最后根据计算和分析结果,对国产600MW超临界汽轮机机组的安全运行提出有实际工程意义的建议。     

K-65-12.8 condensing steam turbine

A new condensing steam turbine K-65-12.8 is considered, which is the continuation of the development of the steam turbine family of 50–70 MW and the fresh steam pressure of 12.8 MPa, such as twocylinder T-50-12.8 and T-60/65-12.8 turbines. The turbine was developed using the modular design. The design and the main distinctive features of the turbine are described, such as a single two-housing cylinder with the steam flow loop; the extraction from the blading section for the regeneration, the inner needs, and heating; and the unification of some assemblies of serial turbines with shorter time of manufacture. The turbine uses the throttling steam distribution; steam from a boiler is supplied to a turbine through a separate valve block consisting of a central shut-off valve and two side control valves. The blading section of a turbine consists of 23 stages: the left flow contains ten stages installed in the inner housing and the right flow contains 13 stages with diaphragm placed in holders installed in the outer housing. The disks of the first 16 stages are forged together with a rotor, and the disks of the rest stages are mounted. Before the two last stages, the uncontrolled steam extraction is performed for the heating of a plant with the heat output of 38–75 GJ/h. Also, a turbine has five regenerative extraction points for feed water heating and the additional steam extraction to a collector for the inner needs with the consumption of up to 10 t/h. The feasibility parameters of a turbine plant are given. The main solutions for the heat flow diagram and the layout of a turbine plant are presented. The main principles and features of the microprocessor electro hydraulic control and protection system are formulated.     

1000MW汽轮机高压转子温度在线仿真计算方法的研究

对1 000MW超超临界汽轮机,利用有限元法验证了热应力监控中以高压内缸内壁温度代替转子外表面温度的正确性;采用惯性环节法、差分法、有限元法分别计算了冷态启动、温态启动、热态启动和极热态启动过程的高压转子的体积平均温度和转子中心温度,并进行了温差计算的精度分析,验证了惯性环节法的精度和适用性,并为惯性环节法在其他大型汽轮机转子热应力监控中的应用给出技术路线。     

300MW汽轮机高、中压汽缸膨胀不畅的原因分析及改进

将300MW汽轮机组膨胀对轴承座和滑销系统的要求进行了叙述,针对国产N300MW-165/535/535汽轮机因缸体膨胀不畅而导致轴瓦冷态负荷分配不均,运行中瓦温过高,汽封出现磨损,内缸进汽部位产生变形、裂纹,暖机时间延长等问题,分析了产生缸体膨胀不畅的种种原因,并提出了消除滑销系统卡涩,改造轴承座底部基础台板润滑面,改进缸体与轴承座推拉结构,改进管道与缸体的连接方式等相应的技术措施.通过这些技术改进解决300MW汽轮机的膨胀不畅问题,达到汽缸膨胀符合机组正常运行的目的.     

超低负荷工况下大功率汽轮机低压缸内温度场分布特性研究

超低负荷下,汽轮机低压缸内的温度分布情况直接影响汽轮机的安全运行。为了更加清晰地分析蒸汽在低压缸内的温度分布特性,采用非平衡凝结流动模型、SST k-ω湍流模型对某300MW汽轮机极低负荷工况下的低压缸流场进行数值模拟,分析了整个低压缸内蒸汽流动特性、做功能力、温度分布以及近零功率时冷却蒸汽参数变化对温度场的影响。结果表明:汽轮机在30%机组热耗验收工况(turbine heat acceptance,THA)时,末级动叶根部出现了回流。在20%THA左右时,末级已经出现了鼓风现象,动静叶顶部出现漩涡,温度明显上升,且此时末级做功为负功率输出。在近零工况下时,低压缸排汽温度与冷却蒸汽流量和冷却蒸汽温度呈线性变化趋势,与冷却蒸汽流量负相关,与冷却蒸汽温度正相关,因此需设置合理的冷却蒸汽流量和温度来控制末两级叶片的出口温度。研究成果可为超低负荷工况下汽轮机的运行提供参考。     

362MW汽轮机高压缸上下缸负温差分析与处理

针对某汽轮机组高压外缸上下缸负温差的问题,通过收集运行工况数据,探讨设备内部结构,对进汽管滑环式密封环卡涩这一问题进行了分析和处理,对缸体及轴封套变形进行全面检查处理,彻底解决了负温差过大的问题.     

Concept of turbines for ultrasupercritical,supercritical, and subcritical steam conditions

The article describes the design features of condensing turbines for ultrasupercritical initial steam conditions (USSC) and large-capacity cogeneration turbines for super- and subcritical steam conditions having increased steam extractions for district heating purposes. For improving the efficiency and reliability indicators of USSC turbines, it is proposed to use forced cooling of the head high-temperature thermally stressed parts of the high- and intermediate-pressure rotors, reaction-type blades of the high-pressure cylinder (HPC) and at least the first stages of the intermediate-pressure cylinder (IPC), the double-wall HPC casing with narrow flanges of its horizontal joints, a rigid HPC rotor, an extended system of regenerative steam extractions without using extractions from the HPC flow path, and the low-pressure cylinder’s inner casing moving in accordance with the IPC thermal expansions. For cogeneration turbines, it is proposed to shift the upper district heating extraction (or its significant part) to the feedwater pump turbine, which will make it possible to improve the turbine plant efficiency and arrange both district heating extractions in the IPC. In addition, in the case of using a disengaging coupling or precision conical bolts in the coupling, this solution will make it possible to disconnect the LPC in shifting the turbine to operate in the cogeneration mode. The article points out the need to intensify turbine development efforts with the use of modern methods for improving their efficiency and reliability involving, in particular, the use of relatively short 3D blades, last stages fitted with longer rotor blades, evaporation techniques for removing moisture in the last-stage diaphragm, and LPC rotor blades with radial grooves on their leading edges.     

300MW汽轮机抽汽温度偏高的试验分析

根据襄樊电厂4台东汽300MW汽轮机抽汽温度偏高的试验情况，分析了抽汽温度偏高的原因，以4号汽轮机组为例计算了汽缸内部泄漏对机组经济性影响。     

Retrofitting Cogeneration Power Stations under Conditions of Reduction or Abandonment of Steam Delivery for Process Needs

Presently, when the structure of energy consumption by industrial enterprises is being changed, many type PT turbine units operate with limitations imposed on their operating conditions, while type R backpressure turbines are often shut down for a long time or even removed from operation. Thus, the problem of using steam previously intended for process needs combined with the loading of the main equipment and additional generation of power and heat becomes urgent for many power stations. Three main ways for solving this problem are examined in this paper. Potential alternatives for retrofitting of cogeneration power stations (TETS) with types PT and R turbines are discussed. Each alternative solves a specific problem brought about by the actual operating conditions of a turbine at a specific TETs. The results of retrofitting of PT-80-130 turbines with an increase in the throughput capacity of the intermediate pressure cylinder (IPC) and R-50-130 turbines with installation of an additional low-pressure cylinder (LPC) are presented. The experience in operation of the retrofitted R-50-130 turbine with an unconventional arrangement where an additional LPC is installed upstream the high-pressure cylinder (HPC) rather than between the generator and HPC is also described. The experience in the upgrading of TETs with installation of bottom steam turbines driven by steam from a process steam extraction that is not demanded for is presented. Depending on the conditions at a specific TETs, a bottom steam turbine can be installed on a new foundation or in the compartment of a dismounted turbine with the use of serviceable auxiliary and heat-exchange equipment.