【摘要】 据最新统计数据,截至2016年底,我国火力发电量占总发电量的71.60%,火力发电的装机容量占总发电装机容量的64.04%。在总发电量中,水力发电量占比不足20%,核能、风能和太阳能发电量之和占比不足10%,因此,火力发电仍然是我国电力能源的支柱。然而,随着人们环保意识的日益加强,低效率、高排放、重污染的传统发电技术已不能满足发电产业健康、可持续发展的需要。超超临界发电技术作为一种高效率、低排放、低污染的新型先进发电技术,其应用将日益广泛。在工程热力学中,水的临界点参数是22.115 MPa和374.15℃,在此参数之上为均匀的单相流体水,这种状态称为超临界状态,在此参数之上运行的机组称为超临界机组。超超临界在物理上并没有明确的对应参数点,对于超超临界机组,各国并没有统一的定义,国内普遍认为当蒸汽压力不小于27 MPa或温度不低于580℃时,即可称为超超临界机组。650℃超超临界技术是目前我国和世界发达国家竞相研究和发展的先进燃煤发电技术,其主蒸汽温度高达650℃、主蒸汽压力高达35MPa,该技术的关键是主蒸汽锅炉管用钢的研发,要求钢种能够承受650℃、35 MPa主蒸汽的高温、高压和腐蚀作用,其研究焦点集中在化学成分的设计上。目前日本和中国已分别独立开发出了各自的成分体系,并研制出了原型钢。日本国立物质材料研究所(简称NIMS)开发出了9Cr-3W-3CoVNbBN钢(代号为MARBN),日本新日铁住金公司开发出了9Cr-3W-3CoNdVNbBN钢(代号为SAVE12AD),我国钢铁研究总院和宝钢开发出了9Cr-2.8W-3CoCuVNbBN钢(代号为G115)。但以上三种钢的工艺性能和使用性能仍处于试验评价阶段,配套焊材和焊接技术也还在研发中。从世界范围看,650℃超超临界锅炉管已有多个不同成分体系的候选钢种,但不同钢种之间的成分差别较大,各开发者对不同化学元素作用的认识也不尽相同,究竟哪一种成分体系是最佳选择并没有明确的定论。本文综述了目前世界上关于650℃超超临界锅炉管候选钢种化学成分的研究现状,分析了钢中化学元素B、N、C、W、Ta、Nd、Co等的作用机理,阐述了化学元素对基体组织、碳化物和高温蠕变性能等的影响。针对650℃超超临界锅炉管用钢的关键技术瓶颈——配套焊材和焊接技术,从焊接性能的角度指出焊材化学成分设计应与管材基体化学成分有益配合,避免二者微量元素的不良结合引起焊接性能劣化,明确了焊材开发中应注意的问题。更多还原

【Abstract】 According to the latest statistics,by the end of 2016,71.60% of total power generation capacity in China was produced by thermal power,64.04% of the total installed capacity in China was contributed by thermal power.Water power in China accounted less than 20% of total power production;nuclear power,wind power and solar power accounted less than 10%.Apparently,thermal power is the backbone of electrical energy in China.Nevertheless,owing to the increasing appeal for environment protection,the traditional power generation technology with low efficiency,high emission and high pollution can’t meet the healthy and sustainable development of power generation industry.While as a new technology with high efficiency,low emission and low pollution,ultra-supercritical power generation technology has aroused great attention and been widely studied.In engineering thermodynamics,the critical parameters of water is 22.115 MPa and 374.15 ℃.Above this parameter,water presents single-phase fluid which is called super critical state.Super critical generator is thermal power generator which serves under the condition of above 22.115 MPa and 374.15℃.There is no specific parameter in physics for ultra-supercri-tical state,and there is also no unified definition for ultra-supercritical generator.It is universally recognized the generator can be called ultra-super critical generator when it served under the steam pressure of above 27 MPa or the steam temperature of above 580℃.650℃ ultra-supercritical technology is an advanced coal-fired power generation technology which has been competitively studied worldwide.The working condition are steam temperature of 650℃ and pressure of 35 MPa.The core technology of 650℃ ultra-supercritical power generator is the steel used for main steam boiler tube,which is required to suffer the 650 ℃,35 MPa steam.The researches of this kind ofsteel mainly focus on the chemical component design.Up to now,Japan and China has developed their own chemical component system and produced their original steel independently.The steel deve-loped by National Institute for Materials Science of Japan is named MARBN(9 Cr-3 W-3 CoVNbBN),the steel developed by Nippon Steel &Sumitomo Metal Corporation is named SAVE12 AD(9 Cr-3 W-3 CoNdVNbBN),and the steel developed by Iron and Steel Research Institute is named G115(9 Cr-2.8 W-3 CoCuVNbBN).However,the processing property and working performance of the three kinds of steels are still under experimental evaluation,and the matched welding material and welding technique are in development as well.Currently,there are several candidate steels with different chemical components for 650℃ ultra-supercritical boiler tube.Different developers have different understandings of the effects caused by various elements,and there is no consensus yet on the best chemical components.The research progress in chemical components of the candidate steel used for 650℃ ultra-supercritical boiler tube is summarized in this article.The action mechanisms of chemical elements such as B,N,C,W,Ta,Nd,Co are analyzed,and the effects of the elements on the matrix structure,carbides,creep property and so forth are elaborated.In view of welding property,it is pointed out that the chemical component of the welding materials should be matched with the tube steel,the welding property degeneration should be avoided.The problems which should be paid attention to during welding materials development are clarified.更多还原