Sun Jian, Wang Tong, Liu Fuguang, Zhang Zhoubo, Chen Yunhui, Lin He, Liu Hui, Zhao Xiaohui, Cheng Xiaole
School of Mechanical and Electrical Engineering, Xi'an Polytechnic University, Xi'an 710048, China.
Xi'an Key Laboratory of Modern Intelligent Textile Equipment, Xi'an 710048, China.
Materials (Basel). 2023 Jun 20;16(12):4474. doi: 10.3390/ma16124474.
In the power plant boiler industry, dissimilar steel welding is widely used in the connection of thermal power generation units. As an important component of the unit, research on the organizational properties of dissimilar steel welded joints has significant guidance for the life design of the joint. For the long-term service state of TP304H/T22 dissimilar steel welded joints, the microstructure's morphological evolution, the microhardness, and the tensile properties of tube samples were analyzed using tests and numerical simulations. The results show that the microstructure of each part of the welded joint was free of damaged features, such as a creep cavity and intergranular cracks. The microhardness of the weld was higher than that of the base metal. In the tensile test, the welded joints broke at the weld metal at room temperature and at the side of the TP304H base metal at a temperature of 550 °C. The tensile fracture morphology demonstrated a change from a ductile fracture to a hybrid fracture when the temperature rose. The fusion zone and base metal on the TP304H side were the stress concentration areas of the welded joint, which easily sprouted cracks. This study holds significant reference value in assessing the safety and reliability of dissimilar steel welded joints in superheater units.
在电站锅炉行业，异种钢焊接广泛应用于火力发电机组的连接。作为机组的重要部件，对异种钢焊接接头组织性能的研究，对接头的寿命设计具有重要的指导意义。针对TP304H/T22异种钢焊接接头的长期服役状态，通过试验和数值模拟分析了管样微观组织的形态演变、显微硬度及拉伸性能。结果表明，焊接接头各部位微观组织无蠕变孔洞、沿晶裂纹等损伤特征。焊缝的显微硬度高于母材。拉伸试验中，室温下焊接接头在焊缝金属处断裂，550℃时在TP304H母材一侧断裂。拉伸断口形貌随温度升高呈现从韧性断裂向混合断裂的转变。TP304H侧的熔合区和母材是焊接接头的应力集中区域，易萌生裂纹。本研究对评估过热器机组异种钢焊接接头的安全性和可靠性具有重要参考价值。
