600℃/620℃二次再热超超临界机组高温部件用材

为提高燃煤发电转化效率,响应国家节能环保的发展策略,公司突破并掌握了再热蒸汽为620℃的超超临界二次再热机组设计制造技术,成为掌握该项技术的首家国内企业。针对该二次再热机组的实际投运,文章介绍了主要高温部件的选材用材情况。     

Static recrystallization behavior of Inconel 718 alloy during thermal deformation

The softening behavior of Inconel 718 alloy at different temperatures was studied using twostage interrupted compression method on Gleeble1500D thermal stimulator, and the 2% offset method was applied to analyze the experimental dates. Finally, the static recrystallization fraction was obtained. At the same times, optical microscope(OM) and transmission electron microscopy(TEM) were employed to investigate the microstructure characteristic. The experimental results showed that the recrystallization was more sensitive to temperature than holding time. The recrystallization process finished quickly above 1 050 ℃, and significantly prolonged below 1 025 ℃. Additionally, the dynamical model of static recrystallization follows the Avrami equation. The nucleating mechanism was characterized by bulging at grain boundary and merging of sub-grain.     

热处理对Inconel718合金组织及力学性能的影响

针对Inconel 718合金的不同用途,分析研究了4种常用热处理工艺对Inconel 718合金组织和力学性能的影响。结果表明:固溶温度超过1020℃时,奥氏体晶粒显著长大。合金中主要析出相有MC、δ、γ’和γ″相。δ相沿晶界分布,1025℃固溶时呈颗粒状少量析出;950℃固溶时呈块状大量析出;直接时效时呈网状不连续分布。同时,δ相对合金的晶粒度影响较大,且其析出数量和形态决定了合金的韧塑性,γ″、γ’相的析出量和尺寸与晶粒尺寸决定了合金的强度变化。