The technology of the welding process is constantly evolving and improving. Engineers and scientists are developing unique new ways to improve the quality and reliability of the welding process. One of such achievements was the invention in the middle of the last century of tubular cored wire for a semiautomatic device. This greatly facilitated the work of welders. A wire for welding a gas-shielding model appeared on the market for metal joining products in 1957, and already in 1961 a self-shielding flux-cored wire was developed and put into production.
To say that a particular type of welding is the best is impossible, each has its own advantages and disadvantages. The use of a certain type of welding is selected depending on the task of the work. Work with flux-cored wire is a popular type of welding that allows high-quality joining of various metals.
Cored wire design
A flux-cored wire for a semiautomatic device is an electrode that has a steel sheath filled with deoxidizing, protective and slag-forming additives. The main component of the material is iron powder, the content of which determines the grade of the wire.
The choice of consumables is made depending on the number of filler components, the characteristics of which and the field of application should coincide with the parameters of the welding rod, as well as the diameter of the wire for welding.
In terms of improving the quality of the wire with the filler differs from an ordinary bar with the following criteria:
- effectively reduces metal spatter;
- increases the speed of the welding process;
- provides an opportunity to carry out the welding process in any position of the parts;
- increases the quality of the weld pool metal, while maintaining the chemical composition of the compound.
Powder Welding Benefits
This type of welding is becoming very popular among masters, even not very highly qualified. This is due to a number of advantages compared to other species. Thus, in flux welding it is difficult to accurately direct the electrode to the junction. When metals are joined in a shielding gas medium, a simple draft makes connection difficult, weakening the protection and spraying the molten metal. Such troubles are excluded when using cored wire for a semiautomatic device.
The main advantages of using filler wire are the following:
- there is no need to use gas equipment to protect the weld pool from the harmful effects of oxygen;
- ease of conducting the welding process;
- low price of wire for welding;
- connection of corner parts in one pass;
- the ability to work outdoors.
The disadvantages of the welding process with wire
Along with many positive aspects of using cored wire for a semiautomatic device, there are also some disadvantages of this type of connection, which can affect both factory and home working conditions.
These include:
- exactingness to observe strict parameters of voltage, current, and also the length of the working area of the electrode;
- increased level of harmful gases and substances;
- in some cases, the need for additional protection.
Types of wire
Structurally, the welding wire can be:
- tubular;
- two-layer;
- with bends of the outer shell.
Bends are created to increase the rigidity of the finished material and prevent the filler from spilling out when squeezing the wire with the rollers of the welding machine.
According to the method of protection, the material is divided into:
- cored wire for a semiautomatic device using shielding gas in the medium;
- self-shielded electrode wire without gas.
Work with a wire with self-protection significantly simplifies the process of joining metals, since the use of gas cylinders is not required.
The use of wire for welding in a cloud of protective gas greatly improves the mechanical properties of the weld.
Cored wire grades
There are many special criteria by which manufacturers make consumables. The brand of wire for welding is most often determined by the composition of the components included in the powder.
It is the right choice of the brand of electrode used that decides the effective implementation of the task:
- E71T-1 flux cored wire is used for welding complex, critical products, as it contributes to the rapid solidification of slag covering the weld pool. This property of the material increases the speed of the operation. The productivity of such a rise welding is 3 kg / h, which cannot be boasted by another type of joint. This wire is made with self-protection.
- When welding thick-walled products in the lower position, E70T-4 wire is often used. In this position, the performance indicator is 18 kg / h, which is the fastest welding. This material is also considered self-protective.
- E70T-1 gas shielding wire allows to show the highest productivity in its equipment class - up to 14 kg / h. Welding with this material allows you to maintain a stable electric arc, even when working with parts that have not been mechanically cleaned. They easily weld dirty or rusty metal structures.
- E70T-5 grade is very practical when working with difficult to weld metals, as it contains slag-forming powder, which removes phosphorus and sulfur from the welding site.
- Seams in an upright position are recommended to be made with electrodes of grades PP-AN7 or PP-AN11. Additives that make up this wire quickly crystallize slag, which eliminates the movement of molten metal down.
- To connect the pipelines, a PPT-7 welding wire is used, which includes zirconium dioxide. This component blocks the path of nitrogen into the weld zone.
Features of powder welding
Most often, wire with additives is used for the operation of a hose semiautomatic device. Therefore, a visual overview of the weld has good accessibility. The connection process itself is not much different from manual arc welding with a consumable electrode.
However, if welding is carried out in several layers, you will have to remove the slag from the previous layer. The not very great strength of flux-cored wire requires the use of an automatic material feed system with an adjustable compression force. Performing operations with a standard wire for welding, with a diameter of 2.6 mm, requires the use of an electric arc of continuous burning.
To perform welding work of high quality, you need to resort to the protection of the weld pool with carbon dioxide.
Of course, the use of semiautomatic devices at home often becomes an economically disadvantageous activity, but there are other ways to use flux-cored wire. The coincidence of the chemical properties of the welding metals and electrodes allows the use of this method for surfacing worn parts.