Influence of parameters of two-jet gas protection on the structure and microhardness of steel45 joints when welding with a consumable electrode

Employees from the Institute of Physics and Mathematics and Mechanics SB RAS and NSTU studied the influence of the parameters of electric arc welding with a consumable electrode under conditions of two-jet gas protection in CO₂ on the structure and microhardness of welded joints with slotted edges made of high-strength steel 45 using the full factorial method experiment.

(a) Diagram of the outflow of protective gas from the welding nozzle with two-jet gas protection. Images of temperature fields after welding: (b) heating (t=60s.); (c) cooling (t=120s.)

In the course of research, an asymmetric distribution of microhardness in the sections of welded joints relative to the axis of the weld was established, which indicates some difference in the structure and properties of the heat-affected zone of the relative weld due to the uneven introduction of heat into each of the welded plates during slotted cutting of the edges. It was found that electric arc welding with a consumable electrode under conditions of double-jet gas protection provides faster distribution and equalization of heat on the surface of the product and reduces its instantaneous overheating, which improves the structural-phase state of the welded joint made of steel 45 and reduces the microhardness gradient in the heat-affected zone. An increase in welding heat input (a simultaneous increase in welding current and welding arc voltage) leads to a decrease in the gradient (peak) of microhardness in the heat-affected zone.

The work was carried out within the framework of the state assignment of the Institute of Physical Problems and Problems of the Siberian Branch of the Russian Academy of Sciences (project FWRW-2021-0003). The research results were published in the journal Metals (IF: 2.695, Q1 in the Metals and Alloys category - according to SJR).

Chinakhov, D.A.; Il'yashchenko, D.P. The Influence of Two-Jet Gas Shielding Parameters on the Structure and Microhardness of Steel 45 Joints during Consumable Electrode Welding. Metals 2023, 13, 1136
https://doi.org/10.3390/met13061136