Influence of 8% CO2 and argon shielding gas mixture on MAG welding of high strength steel (650 MPa) in spray arc
2022
Avisans, Didzis | Boiko, Irina | Avisane, Anita
It is more complicated to weld low alloyed high-strength steel materials than standard structural steel. The chemical composition of these materials makes the process harder as it is important to keep the high strength properties of the steel even after the process is done. An important influence in MAG (Metal Active Gas) welding of such steels makes the choice of the welding wire, welding parameters and shielding gas composition. Appropriate choice of the welding wire and shielding gas is an important issue in welding of low alloyed high-strength steel. Change of the welding parameters changes the heat input, type of welding wire transfer and the welding process in general. Shielding gas can influence the stability of the welding parameters. The influence of shielding gas has been investigated for structural steels (till 275–355 MPa). There are also articles about very high strength steel (900–1000 MPa) MAG welding where the shielding gas influence on the welding joint was investigated. As these investigations show that the influence of Argon mixture with 8% Carbon dioxide (CO2) is much better than mixtures with higher CO2 content, the authors have stated that the same influence can be on low alloyed high strength steel (550–650 MPa) MAG welding. High welding parameters can also influence the welding process. Lower heat input is an important issue in welding of high strength steels. Because of the previously mentioned reasons the influence of 8% CO2 mixture in Argon on MAG welding of low alloyed high strength steel at high welding parameters was investigated. Better results in combination of penetration + inclusions + hardness were reached with lower welding parameters.
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