Metals and Materials International ( IF 3.3 ) Pub Date : 2021-07-07 , DOI: 10.1007/s12540-021-00988-7 Young Wha Ma 1 , Yeon Soo Lee 1 , Kyong Woon Lee 2 , Byeong Ook Kong 2 , Hyun Uk Hong 2
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Abstract
A study for evaluating the weld joint strength reduction factor (WSRF) due to creep was conducted for alloy 740H-P92 dissimilar metal weld joint to be used advanced ultra-supercritical fossil power plants. To this end, a series of the creep rupture tests were carried out for P92 and alloy 740H parent metals and alloy 740H-P92 dissimilar metal weld joint at elevated temperatures ranging from 600 to 700 °C. Additionally, for the creep tested specimens, hardness measurement and microstructure observation were performed. Weldment creep rupture test used specimens of transverse cross-weld type. In the creep test result, weldment creep rupture strength was almost same as that of the P92 parent metal when analyzed as a function of Larson-Miller parameter (LMP). However, when analyzed as a function of creep rupture time for individual temperatures, it showed a tendency to be lower than that of the P92 parent metal after certain times. The difference between two creep strengths increased with increasing time. Based on the analysis result for creep rupture time at each temperature, the WSRF for 100,000 h creep life was determined as 0.84 at 600 °C, 0.72 at 650 °C and 0.58 at 700 °C through extrapolation. Additionally, from the results of investigation on hardness and microstructure, it was shown that the creep life of alloy 740H-P92 dissimilar metal weld joint was dominantly determined by the characteristics of the heat affected zone (HAZ) on P92 side.
Graphic Abstract
中文翻译：
合金 740H 至 P92 异种金属焊接接头中由于蠕变引起的焊接接头强度降低系数的评估
摘要
对用于先进超超临界火力发电厂的合金 740H-P92 异种金属焊接接头进行了评估由于蠕变引起的焊接接头强度折减系数 (WSRF) 的研究。为此，对 P92 和合金 740H 母材以及合金 740H-P92 异种金属焊接接头在 600 至 700 °C 的高温下进行了一系列蠕变断裂试验。此外，对于蠕变试验样品，进行了硬度测量和显微组织观察。焊件蠕变断裂试验使用横向交叉焊缝类型的试样。在蠕变试验结果中，当作为 Larson-Miller 参数 (LMP) 的函数进行分析时，焊件蠕变断裂强度与 P92 母材的蠕变断裂强度几乎相同。然而，当作为各个温度下蠕变破裂时间的函数进行分析时，在一定时间后，它显示出低于 P92 母金属的趋势。两种蠕变强度之间的差异随着时间的增加而增加。根据各温度下蠕变断裂时间的分析结果，通过外推法确定 100,000 h 蠕变寿命的 WSRF 在 600 °C 下为 0.84，在 650 °C 下为 0.72，在 700 °C 下为 0.58。此外，从硬度和显微组织的研究结果表明，740H-P92合金异种金属焊接接头的蠕变寿命主要由P92侧热影响区（HAZ）的特性决定。通过外推法确定 000 h 蠕变寿命在 600 °C 下为 0.84，在 650 °C 下为 0.72，在 700 °C 下为 0.58。此外，从硬度和显微组织的研究结果表明，740H-P92合金异种金属焊接接头的蠕变寿命主要由P92侧热影响区（HAZ）的特性决定。通过外推法确定 000 h 蠕变寿命在 600 °C 下为 0.84，在 650 °C 下为 0.72，在 700 °C 下为 0.58。此外，从硬度和显微组织的研究结果表明，740H-P92合金异种金属焊接接头的蠕变寿命主要由P92侧热影响区（HAZ）的特性决定。
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