The consumables
required for welding work are needed no less than a functional apparatus.
Welding electrodes are a coated steel bar that is used as a material for
welding on joining parts.
Today, products
can be bought almost everywhere: both on display in the bazaar and in specialized
stores. The assortment is huge. The buyer has only one problem: how to choose a
quality product.
Electrode types and selection
There are two
types of products: melting (wire with a special coating) and non-consumable
(tungsten, graphite and electrical carbon). But this feature does not affect
their work in any way, it is much more important to know what the purchased
products will be needed for.
So, according to
this parameter, electrodes for welding steel are divided into:
carbon and low-alloy;
alloyed;
highly alloyed with individual characteristics;
heat-resistant alloyed;
coatings of surface layers with special properties.
Therefore, if
elements are needed for stainless steel, buy those that can be applied to such
alloys. Do not be afraid to consult with experts and choose the right product.
Another feature:
products are afraid of moisture, so the packaging must be sealed without
defects.
As for the brand,
each welder chooses the one with which he is comfortable working. Someone will
say that he prefers ANO-21, and someone will oppose this choice. It all depends
on preference. Therefore, when deciding to buy a particular product, try to
work in advance with different types of this welding material.
Electrode composition
Elements of electrode
coating for inverter welding play a special role:
Slag-forming. Your task is to create a shell of slag around the weld metal
and drops as they fall from the rod into the bath.
Gas generating. During combustion, they form a protective cloud around the
bath and prevent gases from the atmosphere from attacking the molten metal and
pushing it back.
Alloying. When welding for a two-component inverter, mixing occurs: the
base metals with the rod and the metal powders contained in the coating. Depending
on the activity, the chemical composition of the weld may correspond to the
base metal or differ in physical, mechanical and chemical properties (for
example, a surface hardening coating).
Binding and cementing. All components for welding are connected to each
other and to the core, which gives the outer layer the necessary strength.
Coloring. Good elements are marked on the exposed end. However, if a cinder
remains, the stamp is difficult to read. The top surface provides a visual cue
to the welder.
Principle of operation and
characteristics of electrodes
For
manufacturing, special metal rods or conductive wires are used. There are parts
without shells, consisting exclusively of a rod and with a special surface
composition of the product. There are basic, acidic, cellulosic, rutile and
mixed casings. Depending on the purpose it can be ionizing (thin) and
protective (thick).
Many important
points depend on the type of surface: the possibility of welding in different
positions in space, the required welding current, the performance of electric
welding, the tendency to vaporization and the appearance of cracks in the
seams.
The quality of welding with electrodes with an ionizing sheath is inferior
to welding with parts with a protective sheath.
Ionized coated products cannot protect the weld from oxidation and
nitriding.
The acidic sheath of the electrodes consists of manganese, silicon and iron
oxides. When the arc is lengthened, metal elements covered with plaque or rust
are welded, no pores are formed. For electrodes with an acidic sheath, the
current can be constant or alternating and a stable arc occurs. The use of
these products guarantees high welding characteristics (heat is generated
during oxidative reactions).
Electrodes for welding with a basic type of coating consist of a rod and a
sheath (carbonates, fluorine compounds). The seam made by these products is
characterized by ductility, resistance to hot cracking, high resistance to
brittleness as a result of temperature drop, low toxicity, and impact
resistance of the weld metal.
Rutile coating is technologically more advanced than any other type of
casing. Such welding electrodes provide a stable and strong arc burning,
resulting in a high-quality clean seam. Vaporization of a rutile surface is not
affected by joining rusty or damp metal, surface welding with oxidation, or
changing arc length. Such products are distinguished by low toxicity, high
deposition rate when using iron powder, resistance to pore formation and other
positive properties.
Cellulosic type electrodes contain a large amount of organic components.
When one-sided welding with such components, an even seam will be obtained. You
can also weld vertical surfaces from top to bottom.
All welding
electrodes have certain advantages, high efficiency with the ability to use in
adverse conditions with the formation of a professional seam.
