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通过Gleeble热模拟试验,研究了一种低碳铜沉淀纳米相强化铁素体钢焊接热影响区组织及性能,测试了试验钢粗晶区焊接CCT曲线。结果表明,试验钢焊接粗晶区组织主要为贝氏体,其它区域均为铁素体;铜沉淀纳米强化相随热循环不同而发生不同演变,从而引起热影响区性能变化。试验钢粗晶区冲击功及硬度与基体相当,细晶区、临界区及亚临界区冲击功均高于基体,有一定软化现象。在试验t8/5范围内,试验钢粗晶区对焊接热输入较为敏感,随t8/5的增加,组织粗化,并产生较多的粒状贝氏体组织,冲击功降低明显。
A Gleeble thermal simulation experiment was conducted to study the microstructure and properties of heat-affected zone (HAZ) of a low-carbon copper precipitation nano-phase strengthened ferritic steel. The CCT curve of the test steel in the coarse grain region was tested. The results show that the microstructure of the welded steel is mainly bainite and the other areas are ferrite. The evolution of the nanostructured copper precipitates evolves with the different thermal cycles, which leads to the change of the properties of the HAZ. The impact energy and hardness of the coarse grained zone of the test steel are comparable to those of the matrix, and the impact energy in the fine grained zone, the critical zone and the subcritical zone is higher than that of the matrix and has a certain softening phenomenon. In the range of t8 / 5, the coarse grain of the test steel is sensitive to the heat input of welding. With the increase of t8 / 5, the coarsening of the structure and the production of more granular bainite resulted in a significant reduction of impact energy.