Structure of arc welding
Welding electrodes for manual arc welding (welding of steel, welding of cast iron, aluminum welding …). In the welding process, the welding rod is responsible for causing arc and metal addition to the weld. Hand-welded arc welding electrode consists of two main parts: welding rod core and drug sheath.
Construction of welding rods
Part 1: Welding rod core
Core rods are wire segments with the following basic dimensions:
– Length of welding rod L = 250-500 mm
– Core diameter d = 2.0 to 6.0 mm and the size of the rod is called the diameter of the rod
– An unopened cap for stapling pliers of 15-30 mm long, the other end being cleaned with angular bevel angle α = 35o-45o and aperture of 1-1.5 mm for ease of arc solder
– The thickness of the drug layer is about 1-3 mm
Part 2: Cover the medicine
Coating is a mixture of chemicals, minerals, fero-alloys and binders.
Type of welding rod:
Currently there are many standard systems for welding rod classification such as: ISO (International Standard), AWS (USA), BS (UK), DIN (Germany), GOST (Russia), …). The core of the rod, wrapper, type of electric current used for welding, welding space posture, chemical composition and mechanical embankment, …
Acid-resistant sheathed solder (symbol A):
This type of oxide is made of oxides (Fe2O3, MnO, MnO2, SiO2, …) feromangan, …
Welding Solder System Coated Base (Symbol B):
This type of wrapper is made of carbonate (CaCO3, dolomite, CaCO3.MgCO3), feldspar, ferrite (Fe-Si, Fe-Mn, Fe-Ti, …).
Rutilated Rutile Solder (R)
In this kind of packagings, the principal substances are titanium dioxide (rutile, ilmenhite), in addition to feldspar (Na2O3, Al2O3.6SiO2), MgCO3 and CaCO3 or wood pulp, ferrolo …
Welding electrodes with organic coating (denoted O or C):
In this type of drug is mainly: starch, cellulose. When welding produces large amounts of CO2-protecting gases. To overcome the phenomenon of hydrogen buildup and porosity, TiO2, FeO, MnO2, CaF2 and some ferro-ferro-ferric (Fe-Si, Fe-Mn, …) are often added.