A study was made to understand the possible effect of the Al/O ratio on the Charpy V-notch impact properties of submerged arc weld metals within the optimum range of Al/O ratio previously reported to be 0.45–0.75. To vary the Al/O ratio of weld metals in such a narrow range, two base plates different in aluminum content were selected, and a bead-in-groove weld was made on each plate using the same welding condition. From the chemical compositions obtained, the Al/O ratio of each plate was determined to be 0.47 and 0.75. Charpy impact tests showed that the ductile–brittle transition temperature (DBTT) of a low Al/O ratio was about 25 °C lower than that of a high Al/O ratio. The improvement in toughness is concluded to be attributable to the microstructural refinement that can be quantified by two different parameters: AF content increased from 70 to 79% and grain size decreased from 8 to 6 μm. These results also indicated that even a slight variation in aluminum content of base plates could cause a marked variation in weld microstructure and toughness. In addition, the inclusions in the weld of low Al/O ratio were confirmed to be covered by the TiO layer, but no manganese-depleted zone (MDZ) was observed.

进行了一项研究，以了解 Al/O 比对埋弧焊金属夏比 V 型缺口冲击性能的可能影响，之前报道的 Al/O 比最佳范围为 0.45–0.75。为了在如此窄的范围内改变焊缝金属的Al/O比，选择了铝含量不同的两块基板，并使用相同的焊接条件在每块板上进行坡口焊缝。根据获得的化学成分，确定每块板的Al/O比为0.47和0.75。夏比冲击试验表明，低Al/O比的韧脆转变温度（DBTT）比高Al/O比的韧脆转变温度（DBTT）低约25°C。韧性的提高归因于微观结构的细化，微观结构的细化可以通过两个不同的参数来量化：AF 含量从 70% 增加到 79%，晶粒尺寸从 8 μm 减小到 6 μm。这些结果还表明，即使基板铝含量的微小变化也可能导致焊缝微观结构和韧性的显着变化。此外，低Al/O比焊缝中的夹杂物被证实被TiO层覆盖，但没有观察到贫锰区（MDZ）。