P92钢蠕变本构方程测试研究

高温构件因蠕变损伤而引起失效断裂的现象已引起研究人员的重视,针对新型耐热钢P92钢高温蠕变特点,考虑实际工程应用,采用蠕变拉伸试验得到适合P92钢母材蠕变第二阶段的蠕变本构方程,为进一步研究P92钢焊接接头的寿命评估提供了基础数据.     

P92钢高温持久强度试验后组织变化对性能的影响

采用扫描电镜和透射电镜对国产P92钢在600℃下经持久强度试验后的显微组织进行了观察,并研究了组织变化对性能的影响．结果表明：试验1429h前硬度下降主要是由于M23C6的粗化,而后由于大量Laves相析出产生的强化作用使硬度重新上升．当试验6063h后,Laves相粗化使强化效果减弱,硬度再次下降,此时MX仍然保持细小的尺寸,具有较好的强化效果．在整个持久试验过程中,板条马氏体的回复、再结晶导致的位错强化减弱,W、Mo从基体的脱溶导致的固溶强化减弱都对硬度下降起一定作用．     

超超临界火力发电厂机组主蒸汽管SA335-P92钢焊接工艺研究

简述了超超临界机组锅炉主蒸汽管SA335 - P92钢的性能特点,并分析其焊接特性.为获得满足超超临界火力发电机组主蒸汽管SA335 - P92钢的焊接接头性能,详细介绍了应采取的焊接工艺措施.实践证明,通过严格执行施焊工艺,控制现场施工环境,可以获得满足使用性能要求的焊接接头.     

厚壁钢板SA387Gr11CL2焊接接头冲击韧性试验研究

本文针对正火和退火不同的热处理工艺以及平焊和立向上焊不同的焊接位置对SA387Gr11CL2钢焊接接头冲击韧性的影响进行了详细的研究。     

华电国际邹县百万机组耐热P92钢焊接的评定与现状

介绍了邹县发电厂7号超超临界机组,受热面焊口于2005年12月13日开始地面组合焊接省煤器,于2006年9月7日锅炉水压试验一次成功,汽机侧焊接工作于2005年7月开始,于2006年10月27日吹管前焊接工作基本结束.整个工程焊接工程的施工经验.     

焊后热处理温度对P92钢焊缝显微组织和力学性能的影响

采用光学金相显微镜、透射电子显微镜、扫描电子显微镜和力学性能测试等方法,研究了焊后热处理温度对P92钢焊缝显微组织和力学性能的影响.结果表明：热处理前P92钢焊缝硬度高、脆性大;随着焊后热处理温度的提高,P92钢焊缝的硬度降低、缺口冲击韧性升高;采用目前的常规热处理恒温时间、焊后热处理恒温温度达到746℃后,焊缝硬度和缺口冲击韧性可以达到母材的力学性能要求;造成P92钢焊缝硬度降低、缺口冲击性能提高的原因是由于板条马氏体基体向等轴亚晶转变、M23C6及MX相的脱溶析出及M23C6的聚集球化和缓慢长大造成的.     

Effect of diffusible hydrogen content on embrittlement of P92 steel

In the present investigation, varying electrode conditions (dried and contaminated) have been employed during welding of P92 steel to study the effect of diffusible hydrogen level on hydrogen-assisted cracking (HAC). Shielded metal arc welding process was employed to deposit the metal on a P92 steel plate. To evaluate HAC, the Granjon implant test with varying diffusible hydrogen content in the deposited metal was utilized. The diffusible hydrogen level was measured in the deposited metal by using the mercury method. Lower critical stress (LCS), embrittlement index (EI) and normalized critical stress ratio were evaluated from the Granjon implant test. The fracture surface morphology of fractured implant specimens has been studied by using a field emission secondary electron microscope. The P92 steel plate welded by the contaminated electrode with a high level of diffusible hydrogen was found to be more susceptible to HAC. As diffusible hydrogen content increased in the deposited metal, the LCS value and EI were observed to be decreased.     

浅谈P92材料的特点与市场概况

近年来,随着火电市场的大力发展,我国对于P92材料的应用,以四大管道和锅炉为主,日趋成熟,并且在P92材料的供应方面,成功打破了欧美日等国家垄断,实现了国产化。然而就全世界范围内而言,P92材料在国际市场的应用并不多,主要还是集中在中国市场。P92材料距离全世界的普遍推广还是有很长的一段路要走。     

国产S30432钢和T92异种钢焊接接头力学性能和显微组织分析

研究了国产奥氏体S30432钢和马氏体T92异种钢焊接接头的力学性能、各微区的显微组织、硬度分布以及T92钢化学成分变化对焊接接头微观组织的影响,并与进口S30432钢和T92异种钢焊接接头的性能进行了对比.结果表明:国产S30432钢和T92异种钢焊接接头与进口同类型钢焊接接头的力学性能相当,硬度分布情况相同,T92钢侧熔合区的硬度最高,但国产S30432钢和T92异种钢焊接接头的硬度稍低于进口钢.在异种钢焊接接头的T92钢侧熔合区出现块状铁素体带,且发现T92钢不同的Creq当量会影响块状铁素体生成的数量和尺寸.     

SA-335P92钢的焊接

针对在SA-335P91钢的基础上改良开发出来的新钢种SA-335P92钢,进行了2次焊接工艺评定试验.结果表明:该钢种具有优良的高温强度和抗蠕变性能,最高设计工作温度达625℃,可应用于超超临界压力锅炉中的末级过热器集箱、末级再热器集箱和主蒸汽管道等部件.采用较小的焊接线能量、严格控制层间温度及采用合适的热处理规范,有利于获得良好的SA-335P92钢焊接质量.     

国产F92耐热钢焊接接头性能试验与研究

对国产F92钢焊接热影响区的粗晶区进行热模拟试验.不同热处理条件后试样的硬度试验,冲击韧性试验和组织分析表明,焊后热处理对改善焊接接头的塑韧性具有显著作用.焊接工艺试验表明,国产F92钢存在一定的冷裂倾向,实际生产宜采用多层多道焊,层间温度的控制也很重要.     

低合金钢断裂韧性JIc韧脆转变机理的研究

试验研究了球形容器用低合金钢36mm16MnR钢板屈服强度σ,启裂断裂韧性Ji韧脆转变区的变化规律,使用试验数据,利用裂尖向观断裂机制,建立了低合金刚的弹塑性断裂韧性JIC在韧脆转变区的转变规律与16MnR钢母材和焊缝以及A508－III钢焊缝的低温断裂力学的试验结果一致,研究表明低合金断裂韧性的韧脆转变机制是断裂应力σ‘f控制的脆性解理断裂和断裂应变ε^*f控制的塑性韧窝断裂相互竞争机制作用的结果。图5表3参11     

低合金钢焊缝韧脆转变区断裂韧性JIC试验研究

对压力容器用低合金钢40mm 16MnR焊疑缝以及核容器用低合金钢200mmA508-Ⅲ焊缝在韧脆转变区进行了断理解力学试验研究,采用单试样法测试了不同低温下焊疑缝的弹塑性断理解韧性JIC。试验表明：焊缝断理解韧性JIC随温度的下降有明显的韧脆转变特性,同时还发现在JIC迅速下降之前出现双峰的变化,与焊缝冲击功AKV随温度的韧脆转变规律相比有明显不同,因此焊缝断理解韧性JIC随湿度的变化也有其本身固有的韧脆转变规律。     

蒸汽侧氧化膜对超临界机组T92钢管壁温的影响

通过建立T92钢受热管及其蒸汽侧氧化膜的数值分析模型,定量分析了不同厚度氧化膜对T92钢受热管壁温的影响,并在此基础上得出了不同受热条件下导致T92钢管超温运行的氧化膜的临界厚度值.结果表明:随着氧化膜厚度的增加,管壁平均温度和平均温度升高幅度均呈近似线性增加;且管内壁温度越高、管外热流密度越大,氧化膜的临界厚度值越小.因此,当T92钢应用于高温受热面时,需综合考虑壁面热负荷和管内壁温度对氧化膜临界厚度的影响.     

超超临界锅炉用标准钢SA-335P92焊接性试验研究

超临界、超超临界机组的关键技术是多方面的,在设计和制造上都有高难技术,但热强性高,工艺性好、价格低廉的材料开发、应用是最关键的.介绍了超超临界锅炉用钢SA-335P92材料的性能,并通过多种焊接性试验和焊接接头力学性能试验,了解了该钢种的焊接性及焊接接头的机械性能,初步掌握了其焊接工艺,为工厂生产应用打下了基础.     

SA-335P91钢的焊接工艺探讨

随着SA-335P91钢在电站锅炉中的广泛应用,SA-335P91钢的焊接问题备受关注。本文介绍了SA-335P91钢的性能特点和焊接性,阐述了SA-335P91钢的焊接过程中的问题,探讨可以保证良好的焊接质量前提下SA-335P91钢的焊接要点。     

Modelling and experimental studies of alternative heat treatments in Steel 92 to optimise long term stress rupture properties

Abstract

The desire for power plant to give increased generating efficiency and decreased CO₂ emission has led to considerable effort over the last 10–15 years, to develop ferritic–martensitic steels which can be used for steam temperatures up to about 650°C. Examples are the addition of boron and increasing chromium content to 10–12 wt-%. However, high chromium levels have led to problems with long term precipitate stability. One approach which has not been widely explored, is the use of novel heat treatments to optimise the preservice microstructure to give the best long term creep rupture strength. Increased austenitising temperatures and lower tempering temperatures have been examined in Steel 92 (9Cr–0·5Mo–2W) and have produced significant improvements in creep rupture strength at temperatures up to 650°C compared with material given a conventional heat treatment. This has been achieved without any loss in ductility compared with conventional heat treatments. Test data for durations in excess of 40 000 h are presented. Modelling of microstructure evolution based on Monte Carlo simulations has shown important differences especially in the stability of grain boundary M₂₃C₆ and intragranular MX particles, between material with conventional and modified heat treatments. The model predictions are in good agreement with metallographic observations made on material before and after stress rupture testing. Continuum creep damage mechanics modelling based on the microstructural evolution has also been applied to predict creep life of Steel 92 and satisfactory agreement with creep rupture tests has been obtained.     

超级双相不锈钢S32750焊接工艺的探讨

通过试验证明,采用合理的焊接参数,严格控制层间温度及线能量,氩弧焊能保证超级双相不锈钢焊接接头具有合理的相比例,及良好的低温冲击韧性和耐点蚀性能.对实际生产具有指导作用.     

钢中含氮量对钢丝拉拔性能的影响

进行了钢包底吹氮,底吹氮－氩和底吹氩三种精炼工艺对比试验,结果显示,钢中含氮量对钢丝拉拔性能影响显著。钢丝拉拔性能随钢中含氮量下降而有所改善。     

Impact of Fin Arrangement on Heat Transfer and Melting Characteristics of Phase Change Material

Present work investigates the heat transfer and melting behaviour of phase change material(PCM)in six enclosures(enclosure-1 to 6)filled with paraffin wax.Proposed enclosures are equipped with distinct arrangements of the fins while keeping the fin's surface area equal in each case.Comparative analysis has been presented to recognize the suitable fin arrangements that facilitate improved heat transfer and melting rate of the PCM.Left wall of the enclosure is maintained isothermal for the temperature values 335 K,350 K and 365 K.Dimensionless length of the enclosure including fins is ranging between 0 and 1.Results have been illustrated through the estimation of important performance parameters such as energy absorbing capacity,melting rate,enhancement ratio,and Nusselt number.It has been found that melting time(to melt 100％of the PCM)is 60.5％less in enclosure-2(with two fins of equal length)as compared to the enclosure-1,having no fins.Keeping the fin surface area equal,if the longer fin is placed below the shorter fin(enclosure-3),melting time is further decreased by 14.1％as compared to enclosure-2.However,among all the configurations,enclosure-6 with wire-mesh fin structure exhibits minimum melting time which is 68.4％less as compared to the enclosure-1.Based on the findings,it may be concluded that fins are the main driving agent in the enclosure to transfer the heat from heated wall to the PCM.Proper design and positioning of the fins improve the heat transfer rate followed by melting of the PCM in the entire area of the enclosure.Evolution of the favourable vortices and natural convection current in the enclosure accelerate the melting phenomenon and help to reduce charging time.