锅筒斜拉杆焊接接头失效原因分析

通过现场勘查及资料查阅,利用宏观检查、无损检测、金相检验、力学性能试验、化学成分分析、扫描电镜分析、电子能谱分析对锅炉缺陷试样的外观、裂纹状况、金相组织、强度、硬度、冲击韧性、塑性、化学元素含量、高倍显微形貌、裂口晶粒能谱等状况进行了分析。结果表明,这是一起罕见的低碳钢由于非金属硅元素含量超标,形成非金属夹杂物,导致焊接时在热影响区发生纵向热裂纹的质量事故。

Analysis on Failure Causes of Welded Joint of Drum Inclined Rod

Through field investigation and data collection, the appearance, crack condition, metallographic structure, strength, hardness, impact toughness, plasticity, chemical element content and microscopic feature were analyzed by macroscopic examination, nondestructive testing, metallographic examination, mechanical performance test, chemical composition analysis, scanning electron microscope analysis and electronic energy spectrum analysis. Result showed that it was a not common accident. The non-metallic silicon content in low carbon steel exceeded the standard, forming non-metallic inclusions, which caused the quality accident of the longitudinal hot crack in the heat affected zone (HAZ) during the welding process.