Another type of connection which is hardly visible to people is welded connection. When we say this it
doesn’t mean that it is invisible but its visibility is quite like the material in contact and the finishing work
that has been done on it. When we apply any adhesive material we tend not to make it visible from
outline areas so that it looks pleasing same is with the welded connections. One must be think why
welding, when we can have bolted connection? Why welding is needed when it is this much difficult?
The answer is that, Every time it is not possible to provide bolted and riveted connection due to reasons
- Less area is available for bolts or rivets
- Material thickness is not that enough to add bolts.
- Rivet and bolted connection are heavy weighted and increases total weight of structure when it
- Welding eliminates the need for splice plates instead of bolted connections which every time
requires a splice plate for its connection.
- A bolted connection provides some percentage of flexibility to the connection whereas welded
connection provides rigidity.
What is welding?
Welding is a process of connecting metal parts by fusion. When you see a chair, table made of metal their joints are connected through welding only, in a similar way in steel structures the supporting member or the connecting member is welded to the components of connection. Welding is a critical process but very crucial also. It requires perfection because any fault in welding can be dangerous and can sometimes be unpredictable, so in order to provide welding the person must be experienced one. Welding also depends on the parts that to be welded along with the filler material. Most of the welding works are carried out during fabrication process and some of the methods that are used for welding are,
- Shaded metal arc welding (SMAW)
- Submerged arc welding (SAW)
- Gas metal arc welding (GMAW)
- Flux cored arc welding (FCAW)
- Electrogas welding (GMAW- EG) or (FCAW-EG)
- Electrogas welding (ESW)
- Stud welding
- Resistance welding
Selection of type of weld.
Above given welding processes are select by the steel contractor according to the design requirements and productivity point of view. The weld length, round of weld and size of weld that should be provide are detail in the sheets but the fabricator must be aware of the actual possibilities that can get arise while erection.
Types of Weld that are used in steel structures are:
- Fillet weld
- Groove weld
- Plug welds and slot welds
Generally most of the welded connections are fillet because they are easy to prepare, easy to apply and can be easily done in an inaccessible areas. One must know these fact that a complete connection is not generally achieve by only welding or only bolting, sometimes or we can say now a days most of the structures have combine connection type, it might be shop weld. Or field weld. Some common welded connections are
- Shear connections
- Seated beam connections
- Eccentric welded connection