国内某深水导管架为控制重量，首次大规模使用了国产API 2Y-60超高强度钢进行设计和建造。为确保导管架的焊接质量，针对药芯焊丝气保焊（FCAW-G）焊接工艺的热输入开展研究，设置上限、中限、下限3个条件组进行焊接和试验，试验材料为导管架建造用超高强度钢和对应焊材。分析了焊缝金属和热影响区宏观和显微组织的演变，对焊接接头进行了拉伸、弯曲、冲击和硬度试验，并对焊缝金属进行了拉伸试验。试验结果表明，随着热输入的增加，焊接接头中的各类组织逐渐粗化；FCAW-G接头的各项力学性能均满足项目要求；热输入对焊接接头的强度和硬度影响较大，对冲击性能影响不明显。实际生产中，为保证FCAW-G接头性能，应在规定的热输入范围内焊接。

A deep-water jacket widely uses domestic extra high strength steel API 2Y-60 in the design and construction for the first time in China to reduce weight. To ensure the welding quality of the jacket， the heat input of flux cored arc welding with gas shielding （FCAW-G） of extra high strength steel is studied， and the upper， middle and lower limit conditions of heat input are set for welding and testing. Steel plate and corresponding filler metals used for the construction of the jacket are welded. The macrostructure and microstructure of the weld metal and heat-affected zone are analyzed. Tensile， bending， impact and hardness tests are carried out on the weld joints， and tensile tests are performed on the weld metal. The results indicate that the microstructure of the joints becomes gradually coarser with the increase of heat input. The mechanical properties of the FCAW-G joints all meet the requirement of the project. Heat input has a great influence on the strength and hardness of the joints， while has no obvious influence on the impact properties. In order to ensure the properties of the FCAW-G joints， welding beyond the specified heat input should be avoided in the construction of the jacket.