The presence of moisture on the joint surface can create porosity in the weld metal.
It is therefore important that the dew point is monitored so that welders are made aware when moisture is likely to be present.
Water can form as moisture on metal surfaces while welding and it is important to be able to measure ‘Dew Point” while welding lengthy critical joints as conditions can change during the welding process.
Using the PurgeNet™ Dew Point Purging Gas Moisture Sensor™ while welding is the easiest method for indicating when water will condense on solid surfaces in the welding zone.
By using the PurgeNet™ Dew Point Purging Gas Moisture Sensor™ you will have an important predication instrument of when water will form on metal surfaces in the welding environment.
How does water moisture affect the quality of the weld joint?
Under arc conditions, water is broken down into hydrogen and oxygen in atomic form which, when present in weld metal, cause porosity and are known to create cracking in the weld joint.
What is ‘Dew”?
Dew is expressed as drops of liquid water that condense from the atmosphere and onto any solid surface like metal.
What is ‘the Dew Point’?
The dew point is the temperature in ºC or ºF at which air is saturated with water vapour (also referred to as humidity). Below the dew point, water will begin to condense on solid surfaces in the welding environment.
Understanding ‘Dew Point”
Most people are comfortable with a dew-point temperature of 60ºF/16ºC or lower.
As air becomes more humid, the dew point will vary but the temperature will stay the same. If the air around you is very humid and the temperature drops a few degrees, it will reach its dew point.
In contrast, the temperature of air that is very dry will have to drop much more to reach its dew point. The dew point will vary from one part of a country to another.
Welding and quality control personnel who live year round in their working environment will be familiar with their local conditions and will more readily realise the value of a Dew Point Sensor for the security in obtaining the highest quality of critical welds.
Further information about the PurgEye® Dew Point Sensor
The PurgeNet™ Dew Point Purging Gas Moisture Sensor™ accessory has been designed to integrate with most of the Argweld® Weld Purge Monitors® via the PurgeNet™ lead that is supplied with them, thereby giving values and water present on the same screen.
In this way, the user is not forced into the purchase of an expensive, separate Dew Point Monitor that will give its reading elsewhere.
The PurgeNet™ Dew Point Purging Gas Moisture Sensor™ is compatible with the PurgEye® 200, 500 Desk, 600, 1000 Remote and 1500 Site.
Dew Point will vary when there are changes in the atmospheric pressure. The PurgeNet™ Dew Point Purging Gas Moisture Sensor™ takes this into account.
Output
Dew point data will be output to supporting Weld Purge Monitor® with PurgeNet™ for display and PurgeLog™ (on compatible models).
Data Display
Data is displayed on the OLED screen of the Weld Purge Monitor® in split format, so both oxygen (02) and moisture (H20) content are shown as ppm value.
