超超临界电站锅炉结构材料焊接性能研究进展

Development of weldability of structural materials for ultra-supercritical power boilers

针对超超临界电站锅炉的焊接性问题,分析了铁素体/马氏体耐热钢、奥氏体不锈钢及镍基合金等新型锅炉结构材料的抗裂性和焊接接头的力学性能,以及焊接冶金因素对焊接裂纹的影响和焊接热影响区IV型裂纹的形成条件。指出焊接接头的力学不均匀性及对焊接接头力学性能的要求,讨论了焊接接头长期高温服役对力学性能尤其是高温力学性能的影响。从焊接填充材料的成分设计角度,分析了保证焊接接头力学性能的冶金特点,指出焊接材料微量元素控制及焊接工艺控制对保证接头质量的重要性。并展望了超超临界电站锅炉新材料焊接性的研究发展。

In the present work,the cracking and mechanical properties of welded joints have been reviewed for the new structural materials including ferrite/martensite creep resistance steel, austenitic stainless steel, and nickel-based alloy, aiming at the weldability problems of the ultra-supercritical power boilers.In the work, effect of welding metallurgy on the cracks of welded joints and the type IV crack formation of heat affected zone were analyzed.In addition, the mechanical heterogeneity and the requirement of mechanical properties were pointed for the welds.The effect of high-temperature long-duration service on the mechanical properties, especially on the degradation of mechanical properties was discussed.Moreover,from viewpoint of alloy design,the metallurgical characteristics of the consumables were analyzed for ensuring the mechanical properties of welded joints.The minute amount of elements in weld metals and welding technology control were emphasized for the welds quality insurance.Finally, the prospects for the research on weldabifity are proposed in the field of new power boiler materials.