Today I will discussing on the working principles of shielded metal arc welding (SMAW), its advantages and disadvantages. Previously, an article was published on what is SMAW. Check out!
Working principles of SMAW
SMAW is carried out closely just as other arc welding process. It also uses AC or DC power supply which transfer current to the electrode holder in order to produce arc leading to intense heat to melt the tip of the electrode and the joining portion of the workpiece with the arc. This arc length is maintained by the welder by holding a consistent space between the electrode and the weld pool that is form on the workpiece. This workpiece bond as soon as the arc is taken off it. then the joint is obtained.
The followings are the advantages of SMAW;
- Operation result can be readily and reliably obtained.
- Filler and shielding material is provided on the electrode
- SMAW equipment is inexpensive, relatively simple and portable
- Auxiliary gas shielding or granular flux is not required
- Ability to weld variety of metals such as; carbon and low-alloy, steel, high alloy steel, coated steel, tool and die steel, stainless and heat resisting steels, cast irons, copper and copper alloys, nickel and cabalt alloys
- The process is flexible and can be applied to a variety of joint configuration and welding positions
Despite the benefits SMAW offers, it also has some disadvantages. The following are the limitations of SMAW;
- Unable to weld metals with low melting temperature such as, lead, tin, and zinc and their alloys cannot be welded. This is because they have low boiling point and for this welding process that produces intense heat. It will cause immediate vaporization from the solid state.
- The grip end of the electrode (stub-loss) that will be throw away with a small portion of flux can affects the deposition rate. The longer stub-loss change directly into lower deposition efficiency
- Too much high current and too long electrode generate excessive heat within the electrode. This will cause premature breakdown of the flux, when the welding starts. This breakdown triggers a deterioration of the arc characteristics and reduces the level of the shielding
- It is not stable for welding reactive metals such as titanium, zirconium, tantalum, and niobium, due to the shielding provided is not sufficiently inert to prevent contamination of the weld.
- It yields lower deposition rates than other welding process like gas metal arc welding (GMAW) and flux core arc welding (FCAW) process. This is because he maximu m useful current is limited.
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And that is it for this article, working principles of shieded metal arc welding, its advantages and disadvantages. I hope you enjoy reading this article. If so, ask questions, comment, and share. Thanks for reading!