图5.16为Q690NHH耐蚀耐火钢焊接接头各部位微观组织。其中焊缝及焊缝重热区金相组织均为贝氏体；焊接热影响区过热区金相组织为粒状贝氏体；焊接热影响区正火区和不完全正火区金相组织均为贝氏体。      

Figure 5.16 shows the microstructure of each part of the Q690NHH corrosion-resistant and fire-resistant steel welded joint. The metallographic structure of the weld and the reheat zone of the weld are all bainite; the metallographic structure of the superheated zone of the welding heat-affected zone is granular bainite; the metallographic structure of the normalizing zone and the incomplete normalizing zone of the welding heat-affected zone is uniform It is bainite.