P92铁素体耐热钢焊接接头组织与性能的研究
发布时间：2018-09-01 14:08
【摘要】：为应对能源短缺与环境危机,我国电力行业面临着提高煤电使用的经济性以及环保性的严峻考验,而通过提高火电机组的蒸汽参数(温度、压力),可以有效提高火力发电厂效率,因此这就对超(超)临界火电机组锅炉用钢的性能提出了更高的要求。P92钢是在P91钢基础上通过改善合金成分,采用复合多元强化手段而研发出的一种新型9%Cr铁素体耐热钢,P92钢以其优异的综合性能应用于超(超)临界火电机组的锅炉本体过热器、再热器之中,有效的提升了电厂效率和火电机组长期安全运行的稳定性,目前已逐渐应用于我国的超超临界机组建设中。而目前国内对P92钢焊接实际应用研究方面还比较少,所以通过研究合适可行的焊接工艺和焊后热处理工艺,分析接头中组织与性能之间的关系,为P92钢焊接的应用提供理论与数据支持。本文选取由宝钢生产的6 mm板厚的P92铁素体耐热钢作为研究对象,采用钨极氩弧焊(TIG)技术,选用合适的焊接工艺参数对P92钢进行表面自熔焊,随后制定不同焊后热处理工艺。对经不同焊后热处理工艺的接头进行金相组织、力学性能和电化学腐蚀的测试,其中力学性能测试评估包括显微硬度分布、冲击性能以及摩擦磨损性能,金相分析着重对接头中δ-铁素体的大小以及形态进行对比,并对接头的冲击断口形貌和磨损形貌进行微观观察和机理的分析,对P92铁素体耐热钢接头中组织与性能之间的关系进行了研究。研究结果表明:P92钢经TIG自熔焊后在接头中会出现δ-铁素体,δ-铁素体多分布于热影响区,在焊缝中心呈条状且出现几率小,δ-铁素体的硬度要明显低于临近板条马氏体的硬度。P92钢接头中焊缝的平均硬度值要高于母材的平均硬度值,焊态下焊缝硬度最高,冲击韧性最低,这主要因为焊态下焊缝所生成的淬火马氏体组织硬度和脆性很高。经760℃回火热处理,焊缝区显微硬度显著降低,冲击韧性提高,接头中δ-铁素体含量显著减少。随着回火时间的延长,对接头的硬度影响不大,但焊缝冲击韧性提升,断口形貌从韧/脆混合断裂向韧性断裂过渡。同时,经焊后热处理工艺,接头的抗电化学腐蚀能力逐渐减弱,耐磨性能逐渐降低,磨损形貌从磨粒磨损向粘着磨损和表面疲劳磨损转变。本文还对P92钢进行活性氩弧焊(A-TIG)探索性实验,研究结果发现其焊缝的硬度和冲击韧性较传统TIG焊缝差异不大,但是熔深有明显的增加。此种焊接方法焊接P92钢在活性化焊剂的选择上还有待进一步研究。
[Abstract]:In order to cope with the shortage of energy and the environmental crisis, the electric power industry of our country is faced with the severe test of improving the economy and environmental protection of coal power use. Pressure), can effectively improve the efficiency of thermal power plants, so this puts forward higher requirements for the performance of supercritical thermal power unit boiler steel. P92 steel is based on P91 steel by improving the alloy composition. A new type of 9%Cr ferrite heat-resistant steel, P92 steel, developed by means of composite multicomponent strengthening, has been applied to superheater and reheater of supercritical thermal power unit with its excellent comprehensive properties. It has effectively improved the efficiency of power plant and the stability of long-term safe operation of thermal power units, and has been gradually used in the construction of ultra-supercritical units in China. However, there are few researches on the practical application of P92 steel welding in China, so the relationship between microstructure and properties in the joint is analyzed by studying suitable and feasible welding process and post-welding heat treatment process. To provide theoretical and data support for the application of P92 steel welding. In this paper, the P92 ferrite heat-resistant steel with thickness of 6 mm produced by Baosteel is selected as the research object. The surface self-fusion welding of P92 steel is carried out by using TIG welding (TIG) technology and suitable welding process parameters, and then different post-welding heat treatment processes are established. The microstructure, mechanical properties and electrochemical corrosion of joints with different post-weld heat treatment processes were tested. The mechanical properties of the joints were evaluated including microhardness distribution, impact properties and friction and wear properties. Metallographic analysis focuses on the comparison of the size and morphology of 未-ferrite in the joint, and the microcosmic observation and mechanism analysis of the impact fracture and wear morphology of the joint. The relationship between microstructure and properties of P 92 ferrite heat resistant steel joint was studied. The results show that 未 -ferrite will appear in the joint after TIG self-welding, and 未 -ferrite is distributed in the heat-affected zone. The hardness of 未-ferrite is obviously lower than that of adjacent lath martensite. The average hardness of weld is higher than that of base metal. The impact toughness is the lowest, which is mainly due to the high hardness and brittleness of the quenched martensite. After tempering at 760 鈩，
本文编号：2217440
[Abstract]:In order to cope with the shortage of energy and the environmental crisis, the electric power industry of our country is faced with the severe test of improving the economy and environmental protection of coal power use. Pressure), can effectively improve the efficiency of thermal power plants, so this puts forward higher requirements for the performance of supercritical thermal power unit boiler steel. P92 steel is based on P91 steel by improving the alloy composition. A new type of 9%Cr ferrite heat-resistant steel, P92 steel, developed by means of composite multicomponent strengthening, has been applied to superheater and reheater of supercritical thermal power unit with its excellent comprehensive properties. It has effectively improved the efficiency of power plant and the stability of long-term safe operation of thermal power units, and has been gradually used in the construction of ultra-supercritical units in China. However, there are few researches on the practical application of P92 steel welding in China, so the relationship between microstructure and properties in the joint is analyzed by studying suitable and feasible welding process and post-welding heat treatment process. To provide theoretical and data support for the application of P92 steel welding. In this paper, the P92 ferrite heat-resistant steel with thickness of 6 mm produced by Baosteel is selected as the research object. The surface self-fusion welding of P92 steel is carried out by using TIG welding (TIG) technology and suitable welding process parameters, and then different post-welding heat treatment processes are established. The microstructure, mechanical properties and electrochemical corrosion of joints with different post-weld heat treatment processes were tested. The mechanical properties of the joints were evaluated including microhardness distribution, impact properties and friction and wear properties. Metallographic analysis focuses on the comparison of the size and morphology of 未-ferrite in the joint, and the microcosmic observation and mechanism analysis of the impact fracture and wear morphology of the joint. The relationship between microstructure and properties of P 92 ferrite heat resistant steel joint was studied. The results show that 未 -ferrite will appear in the joint after TIG self-welding, and 未 -ferrite is distributed in the heat-affected zone. The hardness of 未-ferrite is obviously lower than that of adjacent lath martensite. The average hardness of weld is higher than that of base metal. The impact toughness is the lowest, which is mainly due to the high hardness and brittleness of the quenched martensite. After tempering at 760 鈩，
本文编号：2217440
本文链接：https://www.wllwen.com/kejilunwen/jiagonggongyi/2217440.html
