高强韧水电站用钢的生产现状及发展趋势

Production status and developing tendency of high strength and toughness steel for hydropower station

概述了近些年来水电站用钢的国内外的生产现状,分析了水电站用钢生产工艺与微观组织之间的关系,认为不同的热处理工艺均能生产出以低碳贝氏体组织为主的钢材;讨论了低碳贝氏体强韧化机制与力学性能之间的关系,碳化物的弥散析出是其主要的强化机制,不同形状的铁素体基体在钢板承受冲击载荷时起到吸收能量的作用是其韧化机制。同时指出了水电站用钢生产过程中的不足主要是产品抗拉强度和-50℃低温冲击韧性值波动较大,超厚规格钢板厚度方向的性能均匀性需要进一步改进。最后指出了水电站用钢的发展趋势,一是需要开发更加优异的热处理生产技术来获得具有更高强度和更高韧性匹配的贝氏体钢,二是需要研究更加优异的轧制技术来细化超特厚钢板厚度1/2处的晶粒和开发优异淬火技术来提高超特厚钢板厚度1/2处的淬透性,最后需要开发先进的热处理回火设备配合优异的工艺来控制回火过程中碳化物的尺寸和分布,通过第二相和基体的协同作用使钢材具备更优异的力学性能。

The production status of steel for hydropower station in recent years at domestic and abroad were summarized. The relationship between production process and microstructure of steel for hydropower station were analyzed. It is considered that different heat treatment processes can produce low carbon bainite steel. The relationship between the strengthening and toughening mechanism and mechanical properties of low carbon bainite were discussed. The main strengthening mechanism is the dispersive precipitation of carbide. The toughening mechanism is that the ferrite matrix with different shapes absorbs energy when the steel plate bears impact load. At the same time, it is also pointed out that the main deficiencies in the production process of hydropower station steel are that the tensile strength and-50 ℃ low temperature impact toughness of produce fluctuate greatly, and the differences of mechanical properties in the thickness direction of ultra-thick steel plate needs to be further improved. Finally, the development trend of steel for hydropower station is pointed out. Firstly, optimized heat treatment technology is needed to obtain bainite steel with higher strength and toughness matching. Secondly, optimized rolling technology is needed to break the grains at 1/2 of the thickness of ultra-thick steel and develop excellent quenching technology to improve the hardenability at 1/2 of the thickness of ultra-thick steel. Finally, it is necessary to develop advanced heat treatment equipment with excellent tempering process to control the size and distribution of carbide in the ferrite matrix, the steel has a better mechanical property through the coordination of the second phase and ferrite.