What is gouging?
In the maintenance and repair industry, welds are often in need of replacement if determined to be worn or defective. Metal gouging and/or backgouging is the process of removing old welds or base metals to restore the weld surface. Gouging is also a popular process used in foundries to remove defects from castings.
Gouging can be achieved through mechanical processes such as grinding, hand milling, routing and chipping and oxyfuel, the latter of which can only be used on carbon steels. Out of the many processes, traditionally the most popular choice is air carbon arc gouging.
Carbon arc gouging uses a carbon/graphite electrode, compressed air, and a power source. The electric arc between the electrode and work piece cuts and melts the metal, while the high velocity air stream blows away the molten metal to leave a clean groove. Though carbon arc gouging is a popular choice, it does come with some disadvantages and safety issues.
What is plasma gouging?
Much like plasma cutting, plasma gouging uses a plasma arc between the torch and workpiece to melt the metal, while utilizing the gas jet to blow it away. This is achieved with specially designed consumables for the plasma cutting system that produce a wider arc. When the plasma torch is held at an angle, only some of the material is blown away. Plasma gouging works on any conductive metal, including mild steel, stainless steel, aluminum, and copper.
What makes plasma gouging superior to carbon arc gouging?
Cleaner – Carbon arc gouging, especially with poorly practice or insufficient air flow, results in contamination within the side walls of the metal which may lead to metallurgical issues. Plasma gouging reduces contamination of the workpiece and minimizes the spread of debris and pollutants at the worksite.
Automation - Powermax plasma cutting systems from Hypertherm allow the user to gouge both freehand or with a track cutter, and can even be made fully automatable with a CNC cutting table. These features ensure clean and consistent gouge profiles every time.
Spot Weld Removal – The Powermax45 plasma system is a fast and cost-effective solution for spot weld removal. Using the precision-gouging consumables and operating at 10-25 Amp output current not only allows the operator better visibility but increases precision to protect the base metal with less fatigue on the wrists, arms, and shoulders.
Safer – As carbon arc gouging pushes the molten metal away with compressed air, fine droplets are created when the metal reacts with the air, resulting in a high level of fumes during the process. Plasma gouging uses gas to push the molten metal away, which generates less metal vaporization and reduces metallic vapour in the work area.
Faster - With the less time spent on secondary grinding work and overall quicker operating speeds, plasma gouging saves time and increases efficiency.
Quieter – Although both processes tend to be on the louder side, plasma gouging is 5-10 decibels quieter than carbon arc; reducing risk of possible hearing loss and communication interference.
Powermax Family
The Powermax family from Hypertherm is a line of portable cutting and gouging systems that are the ideal choice for cutting and gouging of any electrically-conductive metal. Six out the seven machines in the Powermax line offer dedicated gouging operation modes that adjust the amount of pressure traveling to the torch. Hypertherm also offers specialized gouging consumables in four tiers depending on the end user’s needs.
Consumables
Max Control Gouging Consumables
Max control shield is designed for slower rates of metal removal.
- Better control over amount of metal to be removed
- Shallow gouge profile creation
- Light washing capability
Max Removal Gouging Consumables
Ideal for experienced operators looking for faster rates of metal removal.
- Aggressive metal removal
- Deep gouge profile creation
- Extreme metal washing capability
HyAccess Extended Consumables
Designed for cutting or gouging in hard-to-reach places.
- Extended reach
- Improved visibility
- Easy to use
Precision Gouging
Ideal for precise applications, such as spot weld removal.
- Designed to operate at low output current (10-25A)
- Ultra low-density arc for better visibility of defect removal
- Precision performance to protect the base material
Learn more about Hypertherm plasma gouging here.