Basic Types of Welding Joints and Common Welding Terminology

Welding technology involves the melting of metal to create goods. Welders work in a variety of different industries with many different pieces of equipment.It is a fabrication process used to join materials, usually metals or thermoplastics, together. During welding, the pieces to be joined (the workpieces) are melted at the joining interface and usually a filler material is added to form a pool of molten material (the weld pool) that solidifies to become a strong joint.In contrast, Soldering and Brazing do not involve melting the workpiece but rather a lower-melting-point material is melted between the workpieces to bond them together.

With the advent of technology, the process of welding has evolved over the years. However, it’s important to understand the differences between all the existing welding techniques in order to make an educated decision when it comes to picking the right welding technique for the job. Today many processes can be done by automated equipment, however some projects require professional help in order to manually customize the product. Welding requires work and practice, and it’s best learned with the assistance and guidance of professional steel fabricators.

Types of Welded Joints :-
The weld joint is where two or more metal parts are joined by welding. The five basic types of weld joints are the

  1. Butt,
  2. Corner,
  3. Tee,
  4. Lap, and
  5. Edge.

Butt Joint: It is used to join two members aligned in the same plane. This joint is frequently used in plate, sheet metal, and pipe work.

Corner and Tee Joints: These joints are used to join two members located at right angles to each 
other. In cross section, the corner joint forms an L-shape, and the tee joint has the shape of the letter T. 

Lap Joint: This joint is made by lapping one piece of metal over another. This is one of the strongest types of joints available; however, for maximum joint eff

Edge Joints :
An edge joint is used when two pieces of sheet metal must be fastened together and load stresses are not important. Edge joints are usually made by bending the edges of one or both parts upward, placing the two ends parallel to each other, and welding along the outside of the seam formed by the two joined edges. The joint requires no filler rod since the 
edges can be melted down to fill the seam. 
There is some special technical vocabulary (or language) that is used in welding. The basic terms of the welding language include:

Filler Material: When welding two pieces of metal together, we often have to leave a space between the joint. The material that is added to fill this space during the welding process is known as the filler material (or filler metal).
Welding Rod: The term welding rod refers to a form of filler metal that does not conduct an electric current during the welding process

Electrode: In electric-arc welding, the term electrode refers to the component that conducts the current from the electrode holder to the metal being welded. 

Electrodes are classified into two groups: consumable and non-consumable.
* Consumable electrodes not only provide a path for the current but they also supply filler metal to the joint. An example is the electrode used in shielded metal-arc welding.
* Non-consumable electrodes are only used as a conductor for the electrical current, such as in gas
tungsten arc welding. The filler metal for gas tungsten arc welding is a hand fed consumable welding rod.

Flux: Before performing any welding process, the base metal must be cleaned form impurities such as oxides (rust). Unless these oxides are removed by using a proper flux, a faulty weld may result. The term flux refers to a material used to dissolve oxides and release trapped gases and slag (impurities) from the base metal such that the filler metal and the base metal can be fused together. Fluxes come in the form of a paste, powder, or liquid. Different types of fluxes are available and the selection of appropriate flux is usually based on the type of welding and the type of the base metal.

Common TROUBLE's :-
Crack :- A fracture in the weld.
Crater :- A depression at the end of an arc weld.
Porosity :- Bubbles and/or holes in the weld.
Spatter :- Unwanted metal particles expelled during arc and gas welding.
Undercut :- A groove melted into the base metal near the weld toe or root and left unfilled.

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