BASIC TERMS IN WELDING

BASIC TERMS IN WELDING

                             Before moving on to various weld symbols and their combinations, it is important to know the basic terms involved in welding. The basic terms involved in welding has been shown in the fig.


                  These terms shown in the fig. are commonly considered while applying weld symbols in the drawings. The definition of these terms is as follows:-

  1. Base metal:-

 

      One of the two or more metals to be welded together to form a joint.

  2. Bevel angle:-


    The angle formed between the prepared edge of one side of the base metal and a plane perpendicular to the surface of the other side of the base metal.

  3. Fusion zone:-

      It is the area between the two pieces of metal being joined. (When using a rod or tig, you would fuse the metals together)

  4.Groove or included angle:-


      The angle of the groove between the two workpieces that are welded together.

  5.Root:-


      The weld root is the point at which the base metals are closest together.

  6.Root face:-

     Root face is the portion of the groove face within the joint root.

  7.Root opening:-


   Root opening is the separation between the work pieces at the joint root.

  8.Thickness:-


       Thickness is the distance between two surfaces of the base metal which is to be welded.

  9. Throat:-


      The shortest distance between the weld root and the weld face. The throat
determines a fillet weld's size and strength.

  10.Toe:-


     The point at which the weld face and the base metal meet. Weld toes can
experience cracking and undercut.

  11.Weld face:-


     The exposed surface of a weld on the side from which welding occurs.

  12.Weld size:-


      The dimensions of a weld that include leg length, convexity, and concavity.
 

                Apart from the ones discussed above, there are some other terms which are necessary for considering the parameters for weld symbols.


  13.Backing or Back welding:-


      A strip of metal located on the side opposite of the weld that provides a surface
for depositing the first layer ... Weld backing is used for complete penetration
welds.

  14.Back Hand Technique:-


     Moving the electrode along the workpiece opposite the direction of welding.

  15.Bending Jig:-


       A device used for weld testing that bends weld test specimens to test their quality.

  16.Blueprint:-


       A document containing all the instructions necessary for making a project. A blueprint with instructions for welding contains one or more welding symbols.

  17.Chain - intermittent Weld:-


       A type of intermittent weld that requires a sequence of welds on each side of the joint that line up evenly with each other.

  18.Consumable Insert:-


        A type of filler material added to the welded joint. Consumable inserts often add strength to the welded joint.

  19.Fillet Weld Performance Test:-


        A weld test performed on fillet welds that places a fillet weld test specimen onto a load and bends it flat onto itself so that it can be inspected for defects.

  20.Fillet Weld Procedure Test:-


        A visual weld test performed on the weld and heat-affected zone of fillet welds.

  21.Guided-Face and Root-Bend Test:-


         A weld test used for thinner base metals that places a weld test specimen into a jig and bends it 180°. The weld test specimen must not break and must not have defects beyond those specified by the code.

  22.Guided-side Bend Test:-


         A weld test used for thicker base metals that places a weld test specimen into a jig and bends it 180°. The weld test specimen must not break and must not have defects beyond those specified by the code.

  23.Heat-Affected Zone:-


         The portion of the base metal that has not been melted, but its mechanical properties have been altered by the heat of welding.

  24.Reference Line:-


         The horizontal line in the center of the welding symbol from which all elements of the welding symbol are referenced. The reference line is one of the most important elements of the welding symbol.

  25.Root Angle:-


          The angle of the groove at the weld root of the two workpieces.

  26.Weld:-


       A mix of metals that joins at least two separate parts. Welds can be produced by applying heat, or pressure, or both heat and pressure, and they may or may not use an additional filler metal.

  27.Weld Backing:-


        A strip of metal located on the side opposite of the weld that provides a surface for depositing the first layer of metal to prevent molten metal from escaping through the joint. Weld backing is used for complete penetration welds.

  28.Weld Dimension:-


         A specific measurement of a weld. Weld dimensions include length, pitch, and size.

  29.Weld Leg:-


         The distance from the root to the toe of the fillet weld. The size of the fillet weld is determined by the length of its legs.

  30.Weld Spacer:-


          A metal strip that acts as weld backing, but is inserted in the root of a joint of a groove weld. Weld spacing maintains a joint's root opening during welding.
 

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