Tungsten Inclusions

Tungsten inclusion is a discontinuity found only in TIG welding. Particles of tungsten from the electrode can be embedded in a weld when improper welding procedures are used. Typical causes are as follows:

• The Contact of electrode tip with molten weld pool.
• Contact of the filler metal with hot tip of electrode.
• Contamination of  the electrode tip by spatter from the weld pool.
• Exceeds the current limit for a given electrode size or type.
• Extension of electrodes beyond their normal distances from the collet (as with long nozzles) resulting in overheating of the electrode.
• Inadequate tightening of  holding collet or electrode chuck.
• Inadequate shielding gas flow rates or excessive wind drafts resulting in oxidation of the electrode tip.
• Defects such as splits or cracks in the electrode.
• Use of improper shielding gases such as argon - oxygen or argon - CO2 mixtures that are used for gas metal arc welding