Damage Evaluation of a Welded Joint in a Long-term Service-exposed Boiler by Using a Small Punch Creep Test
Damage Evaluation of a Welded Joint in a Long-term Service-exposed Boiler by Using a Small Punch Creep Test
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利用小冲头蠕变试验评价长期使用锅炉焊接接头的损伤
DOI：
10.2355/isijinternational.47.1228
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发表时间：
2007
影响因子：
1.8
通讯作者：
Y. Kohno
中科院分区：
文献类型：
--
作者：
S. Komazaki;T. Sugimoto;Y. Hasegawa;Y. Kohno
对一台实际使用约250000小时的锅炉集箱（1.0Cr - 0.3Mo钢）的焊接接头进行了小冲杆（SP）蠕变试验，以评估蠕变性能的变化。分别从母材、焊缝金属和热影响区（HAZ）截取10×10×0.5 mm的小型板状试样，用于SP蠕变试验和微观结构观察。试验结果表明，长期服役暴露后各部分的蠕变断裂强度均有所下降，特别是在高应力（载荷）条件下。在低应力（载荷）水平下，热影响区的蠕变断裂时间比母材和焊缝金属短，这表明可能存在IV型蠕变损伤。透射电镜（TEM）观察还发现，热影响区的晶界上有膜状（Mo，Fe）6C碳化物析出，同时M23C6碳化物粗化。这些微观结构变化可能导致热影响区蠕变断裂强度出现上述降低。
A small punch (SP) creep test was applied to the welded joint of a boiler header (1.0Cr–0.3Mo steel), which had been actually used for around 250 000 h, to evaluate the changes in creep properties. A miniaturized plate-type specimen of 10×10×0.5 mm was taken from the base metal, weld metal and the heat affected zone (HAZ), respectively, for the SP creep test and microstructure observation. Experimental results revealed that the creep rupture strength of each portion had decreased by long-term service exposure, especially in the high stress (load) conditions. The creep rupture time of the HAZ was shorter than that of the base and weld metals in the low stress (load) levels, suggesting the possibility of Type IV creep damage. TEM observation also revealed that film-like (Mo, Fe)6C carbides precipitated along the grain boundaries in the HAZ, as well as the coarsening of the M23C6 carbides. These microstructural changes were likely to cause the above-mentioned reduction in the creep rupture strength at the HAZ.
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DOI：
--
发表时间：
2022
期刊：
影响因子：
--
作者：
新盛 弘法;高橋可昌
通讯作者：
高橋可昌