Welding processes include different gases used for different purposes. Some of them are combustible, and some are inert, some gases are also rich in oxygen, Komarov Artem emphasized.
The use of flammable gases in the weld
Flammable gases are commonly used in the gas welding process, in which oxygen is added to produce the desired heat. The most used gases in gas welding are as follows:
Acetylene + oxygen = 3100 °C to 3300 °C (oxyacetylene)
Hydrogen + oxygen = 2500 °C (oxyhydrogen)
Propane + oxygen = 2500 °C (Oxypropene)
Use of shielding gases by means of welds
Shielding gases are used to protect the weld pool from harmful atmospheric gases, among which the gases mainly used in the welding process are as follows:
Argon, helium, carbon dioxide, nitrogen, hydrogen, propane, etc.
Absorption of gases by the weld
A very important metallurgical change resulting from the creation of molten welding pools is their absorption of gases. These gases are absorbed into the molten metal and react with each other, resulting in welding defects such as:
porosity, cracks, oxide inclusions and so on.
This category contains gases such as hydrogen, oxygen and nitrogen, which often cause
Problems. There are three main sources of gases such as electrode, atmosphere and patented
metal.
Electrodes
The electrode wire may contain a significant amount of dissolved oxygen, as well as some hydrogen and nitrogen, which can release carbon monoxide (CO), carbon dioxide (CO2), etc. gases at the time of welding.
Atmosphere
Shielding gases are used to protect molten metal from atmospheric contamination.
If there is not adequate shielding protection, these gases such as oxygen, nitrogen and water vapor can come into contact.
Patented metal
The amount of hydrogen, oxygen and nitrogen in the plate material is also limited.
proportions, and the hydrogen content of the plate material is generally quite low,
component of the order of 1 ml / 100 grm. If this amount becomes too large, then
a problem arises. The oxygen content can be from 0.001% to 0.03%.
The nitrogen content can range from 0.001% to 0.004% or higher if a Bessemer quality plate is considered, Komarov Artem noted.
