An engineer from Moscow has developed and patented a new gas atmosphere for arc welding and surfacing of metals, which allows for controlled increase of carbon content in the weld and a sharp increase in steel hardness. The solution is aimed at parts operating under severe abrasive wear conditions – from agricultural machinery to road mechanisms, where surface durability is critical.
The technology is based on a triple gas mixture, which includes acetylene, helium, and carbon monoxide in strictly defined ranges. Acetylene acts as a carbon source, decomposing under the action of the arc and saturating the melt; helium stabilizes the thermal regime and improves bath mixing; and carbon monoxide forms a reducing environment and reduces the burning out of alloying elements.
Tests on low-carbon steel showed that adding helium and acetylene in optimal proportions allows increasing the carbon content in the deposited metal from approximately 0.10% to values up to 0.84% while maintaining a dense weld structure. As a result, a more homogeneous microstructure is formed, up to martensitic-cementite phases, and hardness increases to 600–630 HV, which significantly exceeds the indicators of traditional protective environments.
At the same time, the development also takes into account technological limitations: an excess of acetylene leads to soot formation and porosity, while a lack of helium does not provide a stable effect of improving the structure. In the optimal range, the mixture demonstrates a stable improvement in surfacing quality without metal destruction and surface defects.
The result is a gas system that not only protects the welding zone but actively controls the chemical composition and properties of the deposited layer.