What are causes and prevention of Slag Inclusion in Welding? |

What are causes and prevention of Slag Inclusion in Welding?

  1. Slag inclusion-

Metallic or nonmetallic solid material entrapped within the WM, between weld passes or between WM & BM”.

  • May be in the form of slag or any other foreign material, which does not get a chance to float on the surface of the solidifying WM

MGA17

  • H₂: the most undesirable inclusion (causing: cold crack)
  • Lowers the strength of joint & make it weaker
  • Non- metallic inclusion:-

–Most dangerous

–May be sulphide, oxide, silicate or aluminate type

–Acts as stress raiser

  • Slag inclusions are elongated or globular pockets of metallic oxides and other solid compounds.

Causes for slag inclusion:

–Inadequate cleaning of weld metal between passes

–Rapid rate of welding

–Too large electrode

–improper current

–Long arcs

Prevention :

–Maintain proper current & heat input

–Proper cleaning of weld.

According to the American Society of Mechanical Engineers (ASME) welding defect causes are following :-

  • Poor process conditions
  • Operator error
  • Wrong technique
  • Incorrect consumables
  • Bad weld grooves.

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