为高强钢在低温环境下的应用提供试验数据和建议，本文重点围绕焊接热输入和接头母材的不同交货状态这两个关键影响因素，选取控轧控冷（TMCP）和调质（QT）两种交货状态的20 mm厚Q550D和Q690D高强钢，分别进行1.0 kJ·mm^-1、1.5 kJ·mm^-1和1.9 kJ·mm^-1三种常见的气保焊焊接热输入的接头制备、韧性试验检测和对比分析，进行了不同交货状态下对接接头的母材、焊缝区和热影响区（HAZ）的夏比冲击功及其变化规律，以及韧脆转变温度的研究。结果表明：焊接热输入对接头各位置冲击韧性的影响不明显，而交货状态不同则接头呈现出不同的冲击韧性，其中QT态钢板焊接接头热影响区的冲击韧性要优于母材和焊材，而TMCP态钢板焊接接头热影响区的冲击韧性则低于母材和焊材；对控制工况下的韧脆转变温度的研究表明，本文所用的高强钢低温敏感性较好。

To provide experimental data and recommendations for the application of high-strength steels in low-temperature environments， this paper focuses on two key influencing factors： welding heat input and different delivery conditions of base metals. Two types of high-strength steels， Q550D and Q690D with thicknesses of 20mm， were selected in thermo-mechanically controlled process （TMCP） and quenched and tempered （QT） conditions. Three commonly used gas shielded welding heat inputs of 1.0 kJ·mm^-1， 1.5 kJ·mm^-1， and 1.9 kJ·mm^-1 were applied to prepare the joints. The impact toughness tests were conducted， and the results were analyzed and compared. A systematic study was performed on the Charpy impact energy and transition temperature of the base metal， weld metal， and heat-affected zone （HAZ） in butt joints under different delivery conditions. The results indicate that the effect of welding heat input on the impact toughness of various regions of the joints is insignificant， while the delivery condition significantly affects the impact toughness. Specifically， the impact toughness of the HAZ in QT steel joints is superior to that of the base metal and weld metal， whereas in TMCP steel joints， the impact toughness of the HAZ is lower than that of the base metal and weld metal. The study on the ductile-to-brittle transition temperature under controlled conditions suggests that the high-strength steels used in this study exhibit good low-temperature sensitivity.