铸造技术2025，Vol.46Issue(10)：1003-1013,11.DOI:10.16410/j.issn1000-8365.2025.5111
回火次数对超超临界机组用P92钢焊缝显微组织及力学性能的影响
Influence of Tempering Times on the Microstructure and Mechanical Properties of P92 Steel Welds for Ultra-supercritical Units
摘要
Abstract
To address the issue of repeated tempering during the installation of P92 steel welded joints in ultra-supercritical units,the influence of tempering cycles on the microstructure and mechanical properties of a weld was systematically investigated.The evolution of the grain morphology and the distribution of precipitates in the P92 steel welds were analysed via OM,SEM,EBSD,and TEM characterization techniques.The results reveal that the weld microstructure primarily consists of tempered martensite,M23C6 carbides along lath boundaries,and dispersed δ-Fe phases.With increasing tempering cycles,M23C6 carbides significantly aggregate along martensite lath boundaries and preferentially nucleate and grow at δ-ferrite grain boundaries,eventually forming a continuous carbide network.These findings indicate that multiple tempering treatments regulate carbide precipitation and dislocation substructure rearrangement,leading to a gradual decrease in the microhardness and an improvement in the impact toughness.Notably,after four tempering cycles,some subgrains transform into equiaxed grains,whereas the M23C6 carbides coarsen and segregate at the grain boundaries.This phenomenon not only induces a rapid increase in high-angle grain boundaries but also significantly weakens the solid solution strengthening effect,ultimately resulting in a sharp decline in the microhardness.关键词
P92钢焊缝/回火处理/显微组织/晶粒取向/冲击性能Key words
P92 steel weld seam/tempering treatment/microstructure/grain orientation/impact performance分类
金属材料引用本文复制引用
王瑜,胡鹏飞,坚永鑫,皇志富..回火次数对超超临界机组用P92钢焊缝显微组织及力学性能的影响[J].铸造技术,2025,46(10):1003-1013,11.基金项目
国家市场监督管理总局科技计划(2019MK162HZ) （2019MK162HZ）
