本文第一部分研究了淬火和回火9%Ni钢的焊接性，采用焊接模拟和人工时效来评估低温下热影响区（HAZ）的延展性。还对9%Ni对接焊缝进行了一系列大型拉伸试验，试验结果见第二部分。夏比V型钢筋经过各种焊接模拟循环和后续热处理，并在低温范围内开槽断裂。一般而言，即使在宽限值之间变化，模拟焊接热也会导致钢的冲击性能降低，尽管即使在非常低的试验温度下，它们仍然是可接受的(- 196摄氏度）。人工老化可导致严重脆化，例如塑性变形，然后在200-400°C温度范围内加热。这表明，在9%镍钢结构中使用冷变形或纠正变形时，必须小心。

An investigation on the weldability of a quenched and tempered 9% Ni-steel, using weld simulation and artificial aging to estimate the heat affected zone (HAZ) ductility at cryogenic temperatures is reported in the first part of this paper. A series of large scale tensile tests have also been carried out on 9% Ni butt welds, the results of which are presented in the second part. Charpy-V bars were subjected to various weld simulation cycles and subsequent heat treatments and after notching broken at a range of cryogenic temperatures. The simulated welding heat in general, even where varied between wide limits, causes a decrease in impact properties of the steel, although they are still acceptable even at the very lowest test temperatures (-196°C). Severe embrittlement can result from artificial aging, such as a plastic deformation followed by heating in the 200-400°C temperature range. This suggests that care must be taken when cold deformation is used or distortions are corrected in structures made of 9% Ni-steel.