MIG-MAG welding - SIAD Società Italiana Acetilene e Derivati
MIG-MAG Welding header
MIG-MAG is a welding process which uses energy supplied by an electric arc between a fusible metallic electrode (the weld wire) and the piece to be joined, all under a stream of gas or gas mixtures, the make up of which determines the inert (Metal Inert gas) or active (Metal Active Gas) process.
The metallic electrode or weld wire also acts as a filler metal, the chemical composition of which varies depending upon the base material to be welded.
MIG-MAG welding is used to weld almost all of the common commercially used metals today; it is fast, practical and allows welding to be carried out in any position.
Transfer of the metal from the weld wire to the weld puddle can take place in a number of ways depending both on the electrical parameters and the protective gas or gas mixture used:
1. Short-arc, or short circuit transfer, is a process based on a low influx of heat and low penetration. The short-arc process gives good results on thin materials and sheet metal, and is used successfully to carry out welds which are out of position or where there is a wide gap between the pieces to be welded. Short-arc can be used with all protective gases and gas mixtures but has low productivity if used solely with Carbon Dioxide.
2. Bead transfer is not usually the best method for depositing weld metal given the low efficiency which characterises this process.
3. Spray-arc transfer is an extremely clean and highly efficient process in which the complete absence of scattered droplets means all the material introduced is deposited into the weld pool. Spray-arc welding gives better results if performed using gas mixtures with low Carbon Dioxide content or ternary mixtures from the Stargas® range.
4. Pulsed arc transfer combines the benefits obtainable from short-arc (low heat transfer) and spray-arc (greater productivity). This transfer method is useful for both out of position welds or small-medium thicknesses and both for filling hollows or welding extremely thick materials. Pulsed arc is optimised using mixtures from the Stargas® line, such as Stargon PB for carbon steels, for example, and Hydrostar PB SS. for stainless steels.
Continuous wire feed welding has wide application in almost all industrial sectors, in particular:
Being knowledgeable about the complexities of continuous wire feed welding technology, SIAD is able to provide clients with a vast range of products and consultancy driven by the type of need.
Protective gases have a bearing on the cost of MIG and MAG processes equivalent to between 3-5%. Their importance is, however, fundamental in that, thanks to the use of a mixture specifically prepared for the purpose from the Stargas® line, the entire cost of the process can be reduced by anything up to 15-20%.
STARGON mixtures enable a marked increase in productivity in the manual or automated welding of classic construction steel, reducing spray and fumes.
HELISTAR mixtures noticeably increase the speed of automated applications, reducing the number of passes and cleaning costs and decreasing the amount of harmful fumes produced.
HYDROSTAR mixtures make it possible to optimise the welding of austenitic stainless steels.