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Stick Welding – Shielded Metal Arc Welding
Stick welding is known as Shielded Metal Arc Welding (SMAW). Similarly, MIG welding is known as Gas Metal Arc Welding, or GMAW. The TIG or Heliarc welding is referred as Gas Tungsten Arc Welding, or GTAW.
During TIG welding, consumable rods or electrodes are used. High voltage electric current is sent through the rods or electrodes, and when these are short circuited at the tips, very high heat is generated, causing the electrode or rod tips to melt into tiny molten droplets. These droplets form the weld puddle that combines into the base, or parent metal to form a strong bond or a weld. This process is some times called fusion.
The strength of the weld greatly depends on how far the weld puddle penetrates into the base metal pieces. The correct penetration of weld puddle into the metal greatly depends on the welders skill as well as the speed of weld travel.
Besides above, when carrying out the welding process, utmost care has to be taken to keep away the harmful substance in the atmosphere from the weld puddle or the pool. When harmful substances such as hydrogen, oxygen, and nitrogen contaminate the weld pool it can result in cracking and porosity in the weld once it is harden or cooled. Similarly, the weld can get corroded later. Hence during stick welding, it is important to prevent porosity and cracking to form a strong and durable weld. These are the major defects in stick welding.
During the world war II, it was found that applying a flux coating to the electrode had enabled to keep away the harmful substance of the atmosphere from the weld pool This was achieved by forming a gas shield around the weld pool. Also, the slag developed during the welding would get solidified and act as a protective coating for the weld. The slag can be later chipped off to have a clean weld.
Along with the above, it is important to ensure cleanliness right throughout the welding processes.
Stick welding is widely used to weld mild steel and stainless steel. However, it can be used on welding of aluminum and other metals. Similarly, cast iron can be welded using stick welding, however it is important to ensure specific procedures when using it on cast iron. In particular, the cast iron has to be preheated and cooled down gradually with special attention.
Advantages of Stick welding:
It is very much portable
Stick welding equipment is affordable.
Can be used in various positions and could be used indoors as well as outdoors,
Disadvantages of stick welding:
It is very slow as few inches of weld can be carried out at a time before another electrode is introduced.
Electrode tips get wasted quickly
Very high skill level is needed to produce quality welds.
Low penetration levels can be achieved with many electrodes available.
Stick welding is used in structural construction, using low hydrogen (7018),and 6010 rods. The rod type most commonly used is 6013.
On referring to above, it is noted that although stick welding is an easy and a versatile welding method, one has not only to adhere to specific guidelines but also should know the basics.