CO₂ / MIG / MAG welders are the most heavily used gas-metal-arc machines in any fabrication shop. Wire feeds continuously, the arc burns between wire and work, and shielding gas keeps air out. The process is fast, easy to learn and usable in all positions, covering everything from vehicle repair to heavy structural steel. The Icyrobot NB / NBM range spans 350 A to 500 A and includes single-pulse and double-pulse models.
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Icyrobot Welding & Cutting Equipment Co., Ltd.
Service Hotline: +86-10-61805655 / +86-17268660088
Email: lcy@lcyrobot.com
R&D Centre: Suite 1110, Zeyang Tower, 166 Fushi Road, Shijingshan District, Beijing
Production Base: 1/F, Block 6, Future Sci-Tech City, 165 Yuxiang Street, Luancheng District, Shijiazhuang
CO2 / MIG / MAG Welder
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NB-500A CO2 / MIG / MAG Welding MachineNB-500A CO2 / MIG / MAG gas-shielded welding machine with digital inverter control. Rated at 500 A, it delive…Learn More
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NB-350A CO2 / MIG / MAG Welding MachineCO₂ / MIG / MAG gas-shielded welder NB-350A, 350A / 60% duty cycle. Inverter DC, synergic control, wire diame…Learn More
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NBM-350D Single-Pulse MIG / MAG WelderNBM-350D single-pulse MIG / MAG welding machine with digital inverter control. Rated at 350 A, it provides a …Learn More
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NBM-350DP Double-Pulse MIG / MAG WelderNBM-350DP double-pulse MIG / MAG welding machine with digital inverter control. Rated at 350 A, the double-pu…Learn More
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NBM-350DP-W Double-Pulse Cold MIG/MAG WelderThe NBM-350DP-W double-pulse cold MIG/MAG welder tightens heat-input control beyond standard double pulse, fu…Learn More
Three shielding gases compared
| Process | Shielding gas | Characteristics | Best for |
|---|---|---|---|
| CO₂ (MAG) | Pure CO₂ | Low cost, deep penetration, more spatter | General carbon steel, cost-sensitive work |
| MAG | Ar + CO₂ mix | Less spatter, better bead appearance | High-quality carbon and low-alloy steel |
| MIG | Pure Ar or Ar + He | Stable arc, almost no spatter | Aluminium, stainless, non-ferrous |
Conventional versus pulsed GMAW
Conventional short-circuit and globular transfer hit natural limits on spatter, thin-sheet heat input and out-of-position bead shape. Pulsed GMAW switches current between peak and background tens to hundreds of times per second, achieving one drop per pulse:
- Spatter reduced by 80% or more — post-weld cleaning largely eliminated;
- Heat input precisely controlled, so thin sheet resists burn-through and distortion;
- Vertical and overhead pools are easier to control, with consistent all-position appearance;
- Double pulse adds low-frequency heat modulation on top, producing the regular rippled bead that lets cosmetic parts skip grinding.
Models
- NB-350A — general purpose, the mainstay for structures and repair;
- NB-500A — high current for productive welding of medium plate;
- NBM-350D single pulse — low spatter, thin sheet and all-position work;
- NBM-350DP double pulse — rippled cosmetic welds and aluminium.
Common defects and remedies
| Defect | Cause | Remedy |
|---|---|---|
| Heavy spatter | Parameters outside the short-circuit window, wrong inductance | Match voltage and current, use pulse, switch to mixed gas |
| Porosity | Gas flow too low or too high, draughts, rusty wire, dirty work | Set 15–20 L/min, shield from wind, clean, check gas path |
| Lack of fusion | Low heat input, insufficient weave, narrow groove | Raise current, widen weave, correct bevel |
| Undercut | High voltage, fast travel, wrong gun angle | Lower voltage, slow down, correct angle |
| Irregular wire feed | Worn contact tip, wrong drive-roll pressure, kinked liner | Replace tip, adjust pressure, straighten liner |
Frequently asked questions
350 A or 500 A?
Look at your normal welding current. For 6–12 mm plate at 180–280 A, a 350 A machine is sufficient and cheaper. If you regularly weld above 20 mm or run multi-pass, choose 500 A with a water-cooled gun.
Is a pulse machine worth the premium?
If you run a lot of thin sheet, stainless or aluminium, or if post-weld cleaning labour is significant, payback is typically six to twelve months. For rough, long carbon-steel seams, a conventional machine is better value.
When is a water-cooled gun needed?
Above roughly 300 A at high duty, an air-cooled neck overheats and burns contact tips and nozzles quickly. Water cooling extends continuous running time and spare-part life substantially.
For process and model matching advice, contact our engineers. The standards framework is published by the American Welding Society.
Frequently Asked Questions
350 A or 500 A?
For 180-280 A on 6-12 mm plate, 350 A is more economical. For regular work above 20 mm or multi-pass, choose 500 A with a water-cooled gun.
Is a pulse machine worth the premium?
With lots of thin sheet, stainless or aluminium, or expensive post-weld cleaning, payback is typically six to twelve months. For rough carbon-steel seams, conventional is better value.
When do I need a water-cooled gun?
Above roughly 300 A at high duty, an air-cooled neck overheats and burns tips and nozzles quickly. Water cooling extends continuous running time and spare life.