Introduction about welding processes

Welding :-

Welding is process of joining of two similar or dissimilar materials by the application of heat and with or without the application of pressure and with or without application of filler materials. On Cooling the molten edges fuse together to form a strong joint. A filler material is added to the molten parent metal.

Welding (GMAW)

In simple words-

Process of joining metals/alloys
The process performed by Heat with or without Pressure
Filler metal may or may not be used
The joint will be homogeneous

Classification of Welding:-

Pressure Welding- With Heat & Pressure
Fusion Welding- With Heat & mostly with Filler

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Electroslag Welding (ESW)

ELECTROSLAG WELDING The Process :- Electroslag welding (ESW) is a process that melts and joins metals by heating them with a pool of molten slag held between the metals and continuously feeding a filler wire electrode into it, as shown in Figure. The weld pool is covered with molten slag and moves upward as welding progresses. A pair of water-cooled copper shoes, one in the front of the workpiece and one behind it, keeps the weld pool and the molten slag from breaking out. Similar to SAW , the molten slag in ESW protects the weld metal from air and refines it. Strictly speaking, however, ESW is not an arc welding process, because the arc exists only during the initiation period of the process, that is, when the arc heats up the flux and melts it. The arc is then extinguished, and the resistance heating generated by the electric current passing through the slag keeps it molten. In order to make heating more uniform, the electrode is often oscillated, especially when welding thicker...

Gas–Tungsten arc welding (GTAW)

GTAW The Process Gas–tungsten arc welding (GTAW) is a process that melts and joins metals by heating them with an arc established between a non consumable tungsten electrode and the metals, as shown in Figure. The torch holding the tungsten electrode is connected to a shielding gas cylinder as well as one terminal of the power source, as shown in Figure a . The tungsten electrode is usually in contact with a water-cooled copper tube, called the contact tube, as shown in Figure b , which is connected to the welding cable (cable 1) from the terminal. This allows both the welding current from the power source to enter the electrode and the electrode to be cooled to prevent overheating.The workpiece is connected to the other terminal of the power source through a different cable (cable 2). The shielding gas goes through the torch body and is directed by a nozzle toward the weld pool to protect it from the air. Protection fro...

Shielded metal arc welding (SMAW)

SMAW The Process:- Shielded metal arc welding (SMAW) is a process that melts and joins metals by heating them with an arc established between a sticklike covered electrode and the metals, as shown in Figure below. It is often called stick welding . The electrode holder is connected through a welding cable to one terminal of the power source and the workpiece is connected through a second cable to the other terminal of the power source (Figure a). The core of the covered electrode, the core wire, conducts the electric current to the arc and provides filler metal for the joint. For electrical contact, the top 1.5 cm of the core wire is bare and held by the electrode holder. The electrode holder is essentially a metal clamp with an electrically insulated outside shell for the welder to hold safely. The heat of the arc causes both the core wire and the flux covering at the electrode tip to melt off as droplets (Figure b ). The molten metal collects in the weld pool and solidifies ...

Welding

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