Abstract The microstructural factors that contribute to hardening mechanisms were investigated to explain the effect of post-weld heat treatment (PWHT) on the hardness of P92 steel in IN740H/P92 dissimilar weld joints. This study presents experimental analysis of the distribution of microstructural factors such as precipitate size, precipitate fraction, grain size and dislocation density in the heat-affected zone (HAZ) and base metal (BM) of the martensitic heat-resistant steel. Although precipitates mainly decorated the prior-austenite grain boundaries (PAGBs), packet boundaries (PBs), and block boundaries (BBs), their spatial distribution strongly depended on the distance from fusion line and the PWHT conditions. The grain size and the densities of geometrically necessary dislocations (GNDs) also exhibited a non-uniform distribution. The individual contributions of the microstructural factors to hardness were explained by introducing a simple hardening equation that considers the independent effect of different hardening mechanisms.

中文翻译：

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IN740H/P92异种焊缝焊后热处理对P92钢组织和硬度的影响

摘要 为了解释焊后热处理（PWHT）对IN740H/P92异种焊接接头中P92钢硬度的影响，研究了导致硬化机制的显微组织因素。本研究对马氏体耐热钢的热影响区 (HAZ) 和母材 (BM) 中的析出物尺寸、析出物分数、晶粒尺寸和位错密度等微观组织因素的分布进行了实验分析。虽然析出物主要装饰了原奥氏体晶界 (PAGBs)、包晶界 (PBs) 和块晶界 (BBs)，但它们的空间分布很大程度上取决于距熔合线的距离和 PWHT 条件。晶粒尺寸和几何必要位错 (GND) 的密度也表现出非均匀分布。