2016 №07 (08) DOI of Article
2016 №07 (01)

Automatic Welding 2016 #07
Avtomaticheskaya Svarka (Automatic Welding), #7, 2016, pp. 52-55

Oxygen influence on the process of nitrogen-induced pore formation in consumable electrode arc welding

V.A. Pisarev And S.N. Zhiznyakov

Belarussian National Technical University, 65 Nezavisimost Ave., 220013, Minsk, Belarus Republic. E-mail: niil_svarka@bntu.by
Nitrogen-induced porosity is one of the most common defects in welded joints produced by consumable electrode arc welding, particularly, in open sites. It is believed that in order to produce sound welds in low-carbon and low-alloyed steels, their nitrogen content should not exceed 0.01–0.03 %. At the same time, cases of producing tight welds at up to 0.18 % nitrogen content are found in practice. This is indicative of the fact that alongside nitrogen concentration and temperature, other factors also have a determinant influence on the process of nitrogen-induced pore formation. One of such factors, as shown by the conducted analytical and experimental investigations, is oxygen present in weld pool metal. It is capable of slowing down penetration of nitrogen atoms from the melt into the gas cavity of developing nucleus or bubble (effect of oxygen adsorption inhibition). The newly established regularity was used in development of the technology of CO2 welding of steel structures in open sites under the impact of wind with the speed of up to 8–10 m/s. 11 Ref., 1 Table, 1 Figure.
Keywords: arc welding, pores, nitrogen, adsorption inhibition, tight weld, technology
Received:                04.04.16
Published:               02.08.16
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