摘要:
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。
关键词:
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铜沉淀
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热影响区
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冲击功
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显微硬度
Abstract:
By Gleeble simulation tests,microstructures and properties of the heat affected zone(HAZ) for a low carbon Cu nano-precipitation strengthened ferrite steel are investigated. The results show that the microstructures of HAZ are ferrite except for those in coarse-grain HAZ which are dominated by bainite plus granite bainite. Cu nano-precipitation changes to the thermal cycle course,affecting the properties of HAZ. The coarse-grain HAZ exhibits comparable impact energy and microhardness to the unaffected base metal,while the impact energy in other HAZ regions are higher than the base metal and a certain loss of microhardness is observed as a result of dissolution of the Cu precipitates after the weld thermal cycle. The coarse-grain zone is sensitive to heat input in the range of heat inputs investigated in the study. With the t8/5increasing,the microstructure coarsens and more granular bainites are produced and the impact energy decreases obviously.
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