何晓波,刘文胜,张可,于萌,白玉静

• 1:安阳钢铁集团有限责任公司
• 2:河南钢铁集团有限公司
• 3:安徽工业大学冶金工程学院

摘要(Abstract)：

基于Gleeble-3500热模拟试验，采用光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)技术和显微硬度计等研究了Q500qENH桥梁耐候钢焊接粗晶热影响区的组织转变，绘制了模拟焊接热影响区连续冷却转变曲线(SH-CCT)图，探讨了试验钢的低温韧性随冷速的变化机理。结果表明：粒状贝氏体的相变区间为429～615℃,板条贝氏体的相变区间为330～530℃;当冷速≤10℃/s时，组织为粒状贝氏体，当冷速为10～37.5℃/s时，组织为粒状贝氏体和板条贝氏体，而当冷速≥37.5℃/s时，组织全部为板条贝氏体。随着冷速由1℃/s增加至100℃/s,试验钢的硬度呈现先快速增加后缓慢增加的趋势。拐点为30℃/s,此时的硬度为318 HV0.5。硬度升高是由于组织细化和位错密度提高，细晶强化和位错强化效果增强。当冷速为30～60℃/s时，试验钢具有良好的低温冲击韧性，主要是因为板条贝氏体高比例的大角度晶界阻碍了裂纹的扩展。为了使硬度和韧性实现良好匹配，Q500qENH桥梁耐候钢的焊接热输入应当控制在19～27 kJ/cm的范围。

关键词(KeyWords)： 桥梁耐候钢;SH-CCT图;热影响区;显微组织;低温韧性

Abstract:

Keywords:

基金项目(Foundation): 河南省博士后科研启动项目(202103098);; 安徽省高等学校科学研究项目(2023AH051090)

作者(Author): 何晓波,刘文胜,张可,于萌,白玉静

DOI: 10.13289/j.issn.1009-6264.2024-0253

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