ガスシールドアーク溶接における耐風効果に関する研究(第1報)

試作ノズルの流速分布および噴流形状

抄録

Nowadays a gas shielded arc welding, i.e.a semi-automatic welding, has been popularized in the metal work industry, but it has a disadvantage with respest to the wind resistance. Under windy condition the growth of defects, for example blow hole and crack, cannot be avoided.
In order to eliminate this disadvantage of gas shiedled arc welding, research of the welding nozzle was planned and 3 types of welding nozzles, i.e.A, B and C types, were trial-manufactured.
A shows an axial single-shielded nozzle, B an axial dual-shielded nozzle with inner and outer flows and C a wirling vortex shielded nozzle with axial and tangential flows.
Experiments were carried out on the distribution ofshielding gas (CO₂) velocity, the shape of gas jets and influence of gas flows on welds. Results of the experiments are summarizedas follows:
(1) The distribution of the gas velocity in A type nozzel is indicated in a convergent solid pattern and B type bozzle is indicated in a semi-redial pattern. In the latter, the inner flow being a little and the outer flow much, the so-called "saddle type" distribution can certainly be gained.
(2) On the shape of gas jet, it is observed that C type nozzle may have all patterns from a convergent solid to a complete radial pattern and this type is estimated to be better for practital welding under windy condition than the other nozzles used.
(3) With A type nozzle we have no defects in the welds in the region of gas flow of 70 or 80 1/min concerning the spattering, the shape of bead and the air inclusion.