Gazaltı kaynağı

Nert Gas Weldıng

Inert gas welding is an arc welding method where the heat necessary for the welding is generated by the arc formed between a consumable electrode and the workpieceThe solid wire electrode continuously supplied to the welding area form welding metal by being melted and consumed. The electrode, welding bath, arc and the areas of the workpiece near to the welding machine are protected against the hazardous impact of the atmosphere by the gas or mixed gas supplied from the welding torch. The gas should be able to fully protect the welding area, otherwise even a very small air ingress come out errors on the welding metal.

Benefits:

  • The inert gas welding is a welding method faster than coated electrode arc welding due to the following reasons.
    • Since the wire shaped welding electrode is continuously supplied to the welding area, the welder does not have to stop the welding to replace the consumed electrode as is in the coated electrode arc welding method.
    • Since slag is not formed, there is no slag removing process after each welding pass and higher quality welds are obtained as there is no risk of forming slag residues in the welding metal
    • Because electrodes with smaller diameter than the coated electrode arc welding It has high current density and high metal accumulation speed at same current range
  • The welding metal obtained by the inert gas welding has a low hydrogen content, which is particularly beneficial for steels in hardening properties.
  • Since deep ingression is possible in inert gas welding, it is possible to make small corner welds and it provides a smoother root penetration compared to coated electrode arc welding.
  • Thin materials are often welded with TIG welding method or without using additional metal on the other hand the inert gas welding provides better results on the welding of thin materials than coated electrode arc welding.
  • It is highly suitable for use in both semi-automatic and full-automatic welding systems.

Disadvantages:

  • The inert gas welding equipment are more complex, more expensive and more difficult to transport than coated electrode arc welding equipment.
  • Since the inert gas welding torch should be close to the workpiece, it is more difficult to weld in hardly accessible areas compared to coated electrode arc welding.
  • The welding joints made with inert gas welding and steels having hardening property is more prone to cracking since there is no slag layer that decreases the rate of cooling of the welding metal as is the case in coated electrode arc welding.
  • The inert gas welding requires additional protection against airflow to send away the gas protection from the welding area. Therefore, it is not as suitable as coated electrode arc welding for welding works in outdoor areas.
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The Submerged Welding

Submerged welding is an arc welding method where the heat necessary for the welding is generated by the arc(s) formed between a wasting electrode (or several electrodes) and the workpiece. The arc area welding powder layer as well as the welding metal and base metal close to the weld are protected by the melted welding powder (slag). In submerged welding the electricity flows through the arc and the welding bath formed melted metal and melted slag. The arc heat electrode forms the welding bath that fills up the welding bend by melting the melting powder and base metal The welding powder, which is a protective task, also reacts with the welding base and deoxidize the welding metal.The welding powders used for welding the alloy steels may contain alloy elements that compensate the chemical composition of welding metal. Submerged welding is an automatic welding method. In some submerged arc welding applications two or more electrodes may be fed the welding bend.Electrodes may be fed into in side-by-side (twin arc) welding bath or far enough to ensure that the weld baths are hardened independently from each other; thereby thereby a high welding speed and high metal accumulation speed may be obtained.

Benefits:

  • It is a method with high welding speed and high metal accumlation speed which can be used in the welding of flat and cylindrical parts, tubes with all thicknesses and sizes for hardfacing welds
  • It provides perfect and high mechanical strength welding seams.
  • There is no spatter during arc welding and arc heat is not visible, therefore the welding operator needs less protection.
  • It is possible to weld the weld angle bends in contrast to the other methods.
  • 5. The submerged welding could be performed in both indoor and outdoor areas.

Disadvantages:

  • The submerged welding powders are prone to gain moisture from the air, which is a cause of pores in welding.
  • The base metal must be smooth and not be oil, rust and other contaminants on the base metal surface In order to obtain high quality welds.
  • The spatter should be removed out of the weld seam and this may be difficult in some applications. In multi-pass welding works, the slag should be removed after each pass in order to avoiding slag residuals.
  • The submerged welding method is not suitable for materials thinner than 5 mm because it may able to cause oxidation.
  • The method is suitable for flat, horizontal butt-welding and corner welds, except for some special applications
  • For each metal and alloy is not applicable method.
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