Backing Gas Residual Moisture Analysis
Trailing gas residual moisture analysis measures the moisture in trailing gases to prevent hydrogen-induced porosity and embrittlement at the weld root. Traces of moisture can release hydrogen in the arc.
Physical-chemical mechanism of action
Trailing gas residual moisture analysis measures the moisture content in trailing gases. In the arc, water molecules dissociate and release atomic hydrogen, which can then be bound to metal atoms.
Metallurgical relevance & risks in welding
For reactive metals such as titanium and zirconium, moisture in the trailing gas can lead to hydrogen-induced porosity and embrittlement. This can impair the strength of the weld and cause cracks.
Shop practice & action instructions
Make sure the trailing gas is dry before use. Use a moisture meter to check the residual moisture content. A typical target range for residual moisture in trailing gas is below 0.1 ppm. If this value is exceeded, you must dry or replace the gas.