Influence of covering basicity on toughness and HD of highstrength electrode

After some methods being applied to the electrode which yield strength exceeds 785MPa, the impact work of its deposited metal at -50℃ may averagely exceed 80 J.These methods are adding a small quantity of titanium and boron into deposited metal to form toughness micro-structure, or increasing the covering basicity to purify the weld metal.However, when the covering basicity is excessively high, the impact work at -50℃ can't increase any more;and the increase of the covering basicity makes against decreasing the diffusible hydrogen value in the deposited metal.So other methods have been applied to the electrode, such as dehydrating covering materials at quite high temperature, or repeatedly drying the electrode.Finally, all tests indicate that the deposited metal of the electrode can simultaneously have quite high yield strength, quite high impact work and quite low diffusible hydrogen value under optimizing process parameters.