Taisuke Akamatsu

Oxygen and Nitrogen contents of Multilayer Weld Metal by Submerged Arc Welding

This study was made on the oxygen and nitrogen contents and notch toughness of the multilayered weld metal produced by submerged arc welding.The results obtained are summarized as follows.(1) The oxygen content of multilayered weld metal increased as the number of layered weld metal increased.(2) The nitrogen content of multilayered weld metal is almost constant irrespective of the number of layered weld metal.(3) The silicon content of multilayered weld metal increased as the number of layered weld metal increased, and the oxygen content of multilayered weld metal shows the similar tendency.(4) The manganese content of multilayered weld matal increased by MnO included flux, and decreased by flux without MnO as the number of layered weld metal increased.(5) The carbon content of multilayered weld metal decreased as the number of layered weld metal increased.(6) The impact value of multilayered weld metal is roughly constant, but the value of last layered weld metal decreased slightly.(7) The oxygen and nitrogen contents of weld metal does not change remarkablly irrespective of heat treatment.(8) The oxygen content of weld metal increased as the welding current increased, but the nitrogen content in weld metal decreased as the welding current increased, and the impact value of weld metal generally decreased as the welding current increased.

Various gas atmosphere. Report 2. Submerged arc welding in the Ar-O2 mixture gas atmosphere.

The submerged arc welding in variously mixed argon-oxygen gas atmosphere was studied experimentally. The effects of oxygen partial pressure were investigeted. Especially the effects on oxygen and nitrogen contents of the weld metal by various oxygen partial pressure were measured.The influence of oxygen partial pressure on the absorbed energy by Charpy impact test of these metals were also investigated.The results obtained are summarized as follows.(1) The oxygen content in the weld metal continues to decrease up to 0.015 MPa of oxygen partial pressure. After oxygen partial pressure exceeds this value, the oxygen content of the weld metal begins to increase again.(2) The nitrogen content in the weld metal does not change remarkablly irrespective of oxygen partial pressure.(3) The absorbed energy of weld metal continue to increase up to 0.015 MPa of oxygen partial pressure.After the oxygen partial pressure exceeds this value the absorbed energy of the weld metal begins to decrease again. A colse correlation between absorbed energy and oxygen content of the weld metal was found.