| 高强度桥梁钢Q690q的连续冷却转变行为 |
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| 引用本文： | 周文浩.高强度桥梁钢Q690q的连续冷却转变行为[J].金属热处理,2022,47(9):202-207. |
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| 作者姓名： | 周文浩 |
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| 作者单位： | 湖南华菱湘潭钢铁有限公司 技术质量部, 湖南 湘潭 411101 |
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| 基金项目： | 长株潭国家自主创新示范区专项(2018XK2301) |
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| 摘 要： | 利用MMS-200热模拟试验机、Imager M2m光学显微镜、JSM-6490LV扫描电镜和FV-ARS9000全自动维氏硬度计,对高强度桥梁钢Q690q在细晶奥氏体(晶粒度10级)、粗晶奥氏体(晶粒度6.5级)和细晶形变奥氏体(晶粒度10.5级、压缩变形30%)3种奥氏体状态下的连续冷却转变行为进行了比较研究。结果表明,冷却速率相同时,细晶奥氏体使相变开始温度、转变速率峰值温度和相变结束温度升高,而粗晶奥氏体有助于板条贝氏体和板条马氏体等中低温组织生成,而且生成的板条变得更为细长,但组织中原奥氏体晶界更清晰可见,其硬度明显提高;细晶奥氏体变形后,相变开始温度和转变速率峰值温度更高,从而使铁素体变得粗大,但能减少珠光体转变、促使无碳贝氏体生成,其硬度在冷却速率较低时比细晶奥氏体时要大,冷却速率较高时二者的硬度相差不大。
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| 关 键 词： | 桥梁钢Q690q 控制冷却 显微组织 相变 |
| 收稿时间： | 2022-05-30 |
Continuous cooling transformation behavior of high strength bridge steel Q690q |
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| Zhou Wenhao.Continuous cooling transformation behavior of high strength bridge steel Q690q[J].Heat Treatment of Metals,2022,47(9):202-207. |
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| Authors: | Zhou Wenhao |
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| Affiliation: | Technology and Quality Department, Hunan Valin Xiangtan Iron and Steel Co. , Ltd. , Xiangtan Hunan 411101, China |
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| Abstract: | Continuous cooling transformation behaviors of high strength bridge steel Q690q were studied under three different primary austenite states of fine-grained austenite (grain size of grade 10), coarse-grained austenite (grain size of grade 6.5) and fine-grained deformed austenite (grain size of grade 10.5 and 30% compression deformation) by means of MMS-200 thermo simulator, Imager M2m optical microscope, JSM-6490LV scanning electron microscope and FV-ARS9000 automatic Vickers hardness tester. The results show that when the cooling rate is the same, fine-grained austenite increases phase transformation starting temperature, transformation rate peak temperature and phase transformation finishing temperature, while coarse-grained austenite contributes to the formation of medium and low temperature structures, such as lath bainite and lath martensite, and the lath becomes more elongated, but the prior austenite grain boundary becomes clearer, and its hardness obviously improves. Meanwhile, after the fine grain austenite deformation, the phase transformation starting temperature and transformation rate peak temperature are higher, so that the ferrite becomes bulky, but that can reduce the pearlite transformation and promote the formation of carbon-free bainite, and the hardness is greater than the condition of fine-grained austenite at lower cooling rate, and there is no difference when the cooling rate is higher. |
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| Keywords: | bridge steel Q690q controlled cooling microstructure phase transformation |
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