WELDING & TYPES - OVERVIEW



                            WELDING & TYPES - OVERVIEW

            Welding is define as fabrication work in which joint made by materials usually metals by using high heat to melt the parts together, there is huge variety of weldings as SMAW,GTAW,GMAW,FCAW,SAW etc.
            Generally large numbers of weldings done on different material of jobs as per requirements.out of this we discuss firstly SMAW.

I)               SMAW- SHEILDED METAL ARC WELDING also known as MANUAL METAL ARC WELDING in this welding either AC current or DC current from welding source is used to form electric arc between electrode & metals, the base metal and electrode forming weld pool shielded by melting flux.
   
     Pic01

      

           Above image is picture of SMAW WELDING on 10 inch pipe.

            This process is one of the most popular welding processes established since 1890’s. operation of welder is manual. Power source use for this type of welding AC/DC. Require ampere range in order of 300-400 Amps. Flux can be cellulose, rutile or basic.
            The quality of welding is totally depending on skill and experience of welder as only one hand is involved in welding.
            SMAW universally used process for shop, site & construction. This welding is suitable for all position. The advantage of this welding process is this process is best for maintenance welding, economical and flexible also required simple and low-cost equipment’s.
II)            SAW-SUBMERGED ARC WELDING is mechanised welding as auto/semi type welding, established since 1930’s.
           In this process an arc maintained between end of wire electrode and parent metal, bare wire electrodes melts to form weld pool, arc is submerged under special granular powder flux.
          Power source required for this process is DC supply and ampere range in a range of 750A to 3000A.In this process special granular powder flux is used.
         For this process less skill required but welder must have proper operational experience of machine and operational system. This welding mainly suitable for shop and used where higher thickness used. Very high productivity, no smoke formed during operation as compared to other weddings.
        Excellent quality and no any kind of spatters is specialty of this type of welding. This process fins there application for SAW PIPES & LPG GAS CYLINDERS. Cost of SAW process is very high, suitable only for shop welding.


III) GTAW-GAS TUNGSTEN ARC WELDING is also known as TIG WELDING or ARGON ARC WELDING.
              In this process the arc is maintain between tungsten rod and base metal, fusion with or without filler wire inside gas shielded arc. This process is manual but can be mechanized.
              Power source required as AC or DC, Ampere range in order of 50A to 400A. GTAW process done by inert gases or mixture of gases such as Argon and Helium mixture. The quality is totally depends on welder so welder should have proper skill and experience.
             This welding is most cleanest method as compared to other weddings. Suitable for shop and site for all position. Specially used where welding one side welded joint and second side is not possible, particularly in pipe welding for root run. This process find there application in aircraft and chemical industry.
             Productivity is low, imputed gas affects the quality of welding. Welding eye catch for others. But overall most clean and special type welding.
    Different types of welding done as per requirement and types of application, some of types of welding shown below,

  1)   Pressure Welding – This welding also called as pressure welding in this welding the piese of metal to be joint is heated to plastic state and forced together to external pressure Ex. Resistance Welding.


2)   Fusion Welding – This welding also called as non presuure welding in this welding the material at joint heated to moltern state and then solidify Ex, Gas Welding.

3)   Different processes of welding,
1) MIG Welding (Gas Metal Arc Weldinga (GMAW))
2) TIG Welding (Tungstan Inert Gas Weldinga)
3) SMAW Welding (Shielded Metal Arc Welding)
4) FCAW Welding (Flux-cored Welding)
5) Laser Bean Welding.
6) Resistance Welding.
7) Solid State Welding.
8) Plasma Arc Welding.
9)  Thermo-Chemical Welding.
10)     Atomic Hydrogen Arc Welding.
11)     Thermit Welding.

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