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How to choose the right powder welding machine

by Tech Reporter
20 Mar 2019 at 15:19hrs | Views
The choice of the right powder welding machine can be simple and profitable if you carefully consider the application as well as the advantages of each welding process. It involves searching for a product that is efficient, powerful, easy to handle and, most importantly, suited to the particular needs.

In turn, there are many types of welding processes, from simple oxy-fuel to high-tech laser beam.

So, how do welders select the right one for them?
Examine some commonly used welding processes and which materials they are best suited for.

Types of Welding Machines
There are many different types of welding machines used today for different effects and needs. Every method uses varied tools, equipment, and techniques. There are four which are most commonly applied:

SMAW/Stick: Shielded Metal Arc Welding
Stick welding is a type of arc welding, in which a lightning-bolt-like electric current runs between the electrode, or "welding rod" and the substrate. The electrodes have a flux core, which is a chemical cleaner. It is typically used in construction, steel fabrication, pipeline work, and for repairing heavy equipment.

GMAW/MIG: Gas Metal Arc Welding/Metal Inert Gas
This type of welding also uses a consumable electrode. Instead of using flux to prevent oxidation and other metal-weakening agents, MIG welders use an inert gas, which also runs through the welding gun. This type of welding is easy to learn and can be used on a wide range of metals.

FCAW: Flux Cored Arc Welding
Flux-cored arc welding has all the speed of MIG welding, with the efficiency of stick welding. Like in MIG welding, you have a continuously fed wire running through the gun. However, this wire has a flux core, just like the electrodes used in stick welding. It excludes the necessity of addition of inert gas, needed for welding MIG.

GTAW/TIG: Gas Tungsten Arc Welding/Tungsten Inert Gas
This type does not use a consumable electrode. Instead, the welder uses an external rod to create the molten metal needed to forge the weld. TIG welding is known for its strong, high-quality welds, though it requires a higher level of skill than other types of welding.

Powder Welding Peculiarities

Powder welding is traditionally applied using an oxy-acetylene torch. The workpiece heats with the torch. The powder is introduced into the gas stream from the integral powder hopper and then transferred to the workpiece through a flame.

A dense coating of powder forms a strong bond to the base metal by alloying and diffusion.
This process is similar to the oxy-acetylene process with the exception that the hardfacing takes place at lower temperatures. It reduces to the minimum oxidation and deformation of the workpiece and supplies easy edges floating-up.

Powder welding provides an excellent method for puddling in small patches of material fairly quickly. For this reason, the torch is usually used for repair work, to build up the small gouges and cracks, and to apply the small amounts of material. There are some materials currently available exclusively in powder welding format.

Peculiarities of powder welding are:
  • Low Dilution
  • Easy Application
  • Low Distortion
  • Ideal for Edge Building

It should be noted that adding iron powders to covered electrodes, flux cored wires and metal cored wires are well established today.

Additions of iron powder to covered electrode coatings contribute improvement of welding characteristics. The results are often a smoother and more stable arc, lower spatter losses, improved re-striking as well as good bead appearance, and easy slag removal.

Also, additions of high-purity iron powders in welding electrodes have a positive effect on final weld quality.

Flux-cored wires are produced usually with a high percentage of iron powder in their fill, which allows for very high deposition rates in applications such as vertical up welding. Metal-cored wires have even higher deposition rates than flux-cored wires, and solid wires as the core mainly consist of metal powders. For these wires, choosing the right iron powder is even more critical for final product performance.

For both flux-cored and metal-cored wires, the manufacturing process is decisive in achieving the desired product quality. Consistent grain size distribution, powder density and flow characteristics during form and fill of the wires are all extremely important.

Source - Fülldraht Schweißgerät