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Water-Gas Reaction in Welding Arc

Water-gas reaction in the arc: With moist shielding gas, hydrogen forms from water vapor and carbon monoxide, increasing the hydrogen content. Insufficient gas purity leads to porosity.

Physical-Chemical Mechanism of Action

In arc welding, moist shielding gas reacts with carbon monoxide to form hydrogen (H₂). This process is especially active at high temperatures.

Metallurgical Relevance & Welding Risks

Too high a hydrogen content can lead to porosity in the weld. These pores can impair the strength and mechanical properties of the material, potentially causing cracks and failure.

Workshop Practice & Instructions

To prevent hydrogen reactions, the shielding gas must always be dry. A water vapor content of maximum 50 ppm is recommended. If you suspect moist shielding gas, check gas purity and replace the gas if necessary.

MetallurgieSchweißtechnik

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