3 best methods for welding stainless steel

3 best methods for welding stainless steel

Welding of stainless steel is the primary assembly process used in the manufacture of stainless steel. Stainless steel is a commonly used engineering material due to its high corrosion resistance and cryogenic qualities. A wide range of industries such as food, petrochemicals, chemicals, oil and gas, etc. use stainless steel.

In addition to learning security practices and knowing the right places where better buy stainless steel and welding equipment, it is necessary to discuss welding methods before embarking on a project. You can learn the best methods for welding stainless steel below.

1. Gas arc welding method (GMAW)

Metal Inert Gas (MIG) welding and Metal Active Gas (MAG) welding are both versions of the Gas Arc Welding (GMAW) method, which is better known in the United States and other countries.

MIG / MAG welding can be used both on thin sheets and on thick profiles. An arc is created between a wire electrode and the workpiece, melting the two together to form a weld pool. In addition to providing heat, the wire acts as a filler metal for the solder joint. To solder, the wire is fed through a copper contact tube (contact tip). A shielding gas surrounds the wire and protects the weld pool from the surrounding atmosphere. The choice of shielding gas depends on the material and the application. A motor feeds the wire from a spool, while the welder drives the torch along the parting line. The wires can be solid or cored. Consumables are often less expensive than those for other processes. The process is very productive due to constant feeding.

The feed controls wire feed speed and arc length, while travel speed and wire position are manually adjusted. When not directly handled by a welder, the process can be automated, but manual adjustments may be required while welding. Automatic welding is described as requiring no manual intervention.

What is the MIG / MAG difference?

The type of shielding gas used is the only distinction between the two.

The composition of the shielding gas affects arc stability, weld profile, metal transfer, penetration and spatter.

This type of welding uses inert gases or combinations of gases as shielding gases. Argon and helium are inert gases commonly used for MIG welding of non-ferrous metals such as aluminum. Inert gases do not react with the sealant or the weld puddle.

This type of welding uses active shielding gases. In the molten bath, these gases can react with the filler metal, modifying its chemical and / or mechanical properties.

2. Metal arc welding method (SMAW)

This method of welding is done by hand using a stick. The stick creates an arc between the metals to be connected.

This is commonly used for soldering steel, iron and mild steel pipe using the open V-shaped groove.

The welder must be able to weld to a level that passes a destructive form of bend test. Under armor arc welding is used to join alloy steels, carbon steel, stainless steel, ductile iron and cast iron. Aluminum is rarely used.

Limitations of the SMAW process

1. Low melting temperature metals like zinc, tin and lead are not SMAW soldered. Since these metals have low boiling points, the high heat of the SMAW arc causes them to vaporize. This method is also unsuitable for welding reactive metals such as zirconium, titanium, niobium due to the lack of inert shielding.
2. The procedure generates lower deposit rates than GMAW and FCAW. The maximum usable current limits the deposition rate. The maximum usable current limits the deposition rate.
3. In SMAW electrodes, excessive heat is generated due to long electrodes or high current. After the start of welding, the temperature of the coating rises to a point where it degrades prematurely. This failure weakens the arc characteristics and decreases the shielding. The amount of current used is controlled to prevent overheating of the electrodes and rupture of the coating. Due to the restricted usable current, the deposit rates are lower than GMAW or FCAW.
4. Another concern is heel loss. The tip is the gripping end of the discarded SMAW electrode. It is made up of the core yarn and part of the blanket length. The loss of stub reduces the efficiency of the deposit but not the rate. Longer section losses reduce the efficiency of the deposit.
5. The operator factor for SMAW is generally smaller than for continuous electrode processes like GMAW or FCAW.

Low deposition rates and a smaller operator factor decrease the use of SMAW when a large volume of filler metal is required. In these cases, the weld completion rates may be too slow and the welding costs may be too high.

3. Flux Cored Arc Welding Method (FCAW)

This was created to replace shield welding. Semi-automatic arc welding is popular in construction because of its speed and portability. This approach can be used in different welding projects. The variables may depend on the welder model and the type of wire used.

Different voltage levels, operating angles, polarities and wire feed speeds add to the flexibility. Newly joined metal cools faster due to the faster welding speeds. When using flux cored wire, the welder should inspect the porosity of the welded joint.

Conclusion

Welding stainless steel is more difficult than other welds, but it is possible. You can achieve a strong and durable weld using the right equipment, temperature control, and filler material.