Selecting a Quality MIG Wire

Supplier: Blackwoods
13 August, 2013

Selecting a quality MIG wire that is suitable to the application is vital.

Selecting a Quality MIG wire is Critical to Your Weld Application

  • A plate with surface contaminants and the right MIG wire for that application may make some pre-welding operations obsolete
  • A quality MIG wire will provide accuracy in wire placement and consistent in the weld, making rework less of an issue

Common Mistakes in Choosing MIG Wire

  • The most common type of MIG wire for welding mild steel is ER70S-6
  • Choose ER70S-6 wire for welding on plate that has mill scale or surface contaminants as this wire incorporates the proper deoxidiser to combat these issues
  • A deoxidiser absorbs oxygen so that it vaporises into the arc or forms as scale oxidises
  • ER70S-6 creates a smooth transition from the weld to the base metal known as wash-in, or tie-in.  Better wash-in may be a requirement in applications subject to fatigue

The Effect of Wire Diameter

  • Consistent wire diameter is critical to ensure proper current passage from the contact tip to the wire
  • Undersized wire causes arcing between the wire and inside diameter of the tip, which usually erodes the inside diameter of the tip and eventually fuses the tip to the wire
  • Oversized wire causes excessive feeding force, tip blockage, wire slippage and therefore downtime