Presentation on theme: "NTUU “KPI”, UFU, PWI TQC E1815-01 Ponomarev V., Slivinsky A. MIG/MAG spray and streaming metal transfer modes - Welding conditions for these metal transfer."— Presentation transcript:
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. MIG/MAG spray and streaming metal transfer modes - Welding conditions for these metal transfer modes - Their advantages and limitations
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. Short-circuiting Globular Streaming rotating Streaming Spray MIG-Pulsed Transfer modes versus welding current and arc voltage UaUa IwIw Transition current CO 2, or argon based mixtures Argon based mixtures
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. Globular – spray transfer transition Current Transition current Rate of droplet transfer Droplet diameter 180 A I w < I tr (190 А) AWS ER70S mm; Ar 2 %O A I w > I tr IwIw F emz 250 A IwIw F emz IwIw F emr
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. Transition current for different electrode materials and diameters as well as for different shielding mixtures Electrode wire material Electrode wire diameter, mm Shielding mixture Transition current, А Low-carbon steel 0,8 1,0 1,2 1,6 95%Ar + 5%CO Low-carbon steel 0,8 1,0 1,2 1,6 80%Ar + 20%CO Stainless steel 0,9 1,0 1,2 1,6 98%Ar + 2%O Aluminium 0,8 1,0 1,2 1,6 Argon
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. Examples of spray metal transfer 1 mm; Ar+5%O 2 ; 197 А The welding current slightly exceeds the transition current level 1 mm; Ar+2%O 2 ; 211 А The droplets are transferred in line with electrode rather than along the shortest path between the electrode and workpiece that is typical for this mode of the metal transfer.
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. The spray transfer can be experienced at different arc lengths Melting rate: 8.1 m/min 8.8 m/min 9.5 m/min The shorter is the arc, the longer becomes the electrode extension (provided the contact tube – to - work distance is kept changeless) and, as a result, the electrode gets more intensive preheating by the current and therefore its melting rate rises (low-carbon wire of 1 mm and 211 А for all three tests).
NTUU “KPI”, UFU, PWI TQC E Ponomarev V., Slivinsky A. Welding conditions and application sphere of the spray and streaming transfers Welding conditions for spray and streaming transfers: 1. High arc voltage and welding current; 2. Shielding: argon based mixtures. MIG/MAG spray and streaming transfer application is restricted to welding only in the flat position because, in spite of the fact that all droplets are getting into the weld pool, the pool itself is too large to be properly controlled when welding in the vertical or overhead position.