In this study, the microstructural features and microtexture evolution of API X-65 steel welded to UNS S32750 stainless steel were evaluated. The weldments were produced with the different heat input (HI) values: 0.68 and 0.78 kJ/mm. The samples were then characterized by means of the electron backscatter diffraction analysis. The obtained results showed that the microtexture components formed in the UNS S32750 heat-affected zones (HAZs) and the UNS S32750 base metal were the same. However, the microtexture of the API X-65 HAZs was significantly affected by the HI values in comparison to that of the API X-65 parent metal. A random orientation of grains and also a non-uniform distribution of both austenite and ferrite phases were observed in the weld zones. It was revealed that with decreasing the HI value, the austenite’s fractions decreased; hence, almost equal fractions of austenite and ferrite phases were formed in the weldment employing the HI value of 0.68 kJ/mm. It was inferred that the kernel average misorientation and fractions of the especial boundaries were not influenced by the changes in the HI values. Moreover, it was observed that the weld metals showed slightly better impact resistance in comparison to the base metals.

在这项研究中，评估了焊接到UNS S32750不锈钢上的API X-65钢的显微组织特征和微观组织演变。生产的焊件具有不同的热输入（HI）值：0.68和0.78 kJ / mm。然后通过电子反向散射衍射分析对样品进行表征。所得结果表明，在UNS S32750热影响区（HAZs）和UNS S32750贱金属中形成的微观组织相同。但是，与API X-65母金属相比，HI值显着影响了API X-65 HAZ的微观结构。在焊接区中观察到晶粒的随机取向以及奥氏体和铁素体相的不均匀分布。结果表明，随着HI值的降低，奥氏体的分数降低。因此，采用0.68 kJ / mm的HI值在焊件中形成几乎相等的奥氏体相和铁素体相。可以推断，籽粒平均取向错误和特殊边界的分数不受HI值变化的影响。此外，观察到，与母材相比，焊接金属的耐冲击性略好。