A carbon arc melts the metal & a blast of air violently blows it away, creating a groove. It produces a lot of fumes containing metal vapor, carbon dust & other metallic byproducts. These can be hazardous if inhaled. It’s essential to wear proper ear protection for the plasma-cutting process.
High-Intensity Arc
Welders need high levels of energy to weld metals together. An electric current passing through the torch transforms this energy into heat during arc welding. This heat travels through the weld puddle and melts it, forming a new material at the point of contact with the base metal. Weading a given size weld on the thick plate at 175 amps, 25 volts, and three pm generates 87,500 energy per linear inch. This amount of energy causes the weld to have locked-in tensile stresses equal to the yield strength of the base metal.
If the weld is not restrained (by clamps or jigs that hold it in place) during the welding process, these internal stresses will cause movement of the weldment after it cools. Air carbon arc gouging produces fumes with high concentrations of metal vapor, carbon dust, and other metallic byproducts. These can pose health problems if exposed in sufficient quantities. Plasma cutting, on the other hand, produces a smaller volume of fumes. Invest in a mini torch adapter for a faster and safer alternative. It prevents carbon and trace metal accumulation and requires less oxygen to operate.
High-Pressure Air
High-pressure compressed air is needed for air carbon-arc cutting, or PAC welding, to expel the molten metal being cut. It helps to reduce dross formation and provides a better edge quality on the workpiece. Different configurations are required depending on the cutting goals. If inert gas is used as the plasma gas, the molten metal is protected from the surrounding atmosphere and less reactive with the air.
This method is preferred for stainless steel and other corrosion-resistant alloys as it produces no oxidation and a clean groove that can be rewelded without additional cleanup. Air carbon-arc gouging is less expensive than plasma gouging because it can use already-existing welding power and air supplies. However, the filtration system for the compressed air must be sized to achieve the required high pressure and flow rate. It can add to the total capital cost of this type of equipment.
Torch Head
It’s pretty scary and dangerous when your torch head pops in the middle of a project. It can also leave your work looking unprofessional. It is usually caused by dirt in the nozzle. Make sure you have the proper sized nozzle for your torch and that it is clean. Flashback arrestors are safety devices installed between the gas supply hoses and the torch to prevent the flame from burning back into the cylinders (flashback) or exploding (backfire).
They are typically located on the downstream side of the regulator and cylinder but can be on either side. Air carbon arc cutting, or metal arc gouging, is a repair process that uses the heat of an electric arc to cut through the weakened surface of a component. All standard welding precautions apply to this type of cutting, but a few extra precautions should be taken.
Ear Protection
The human ear is a sensitive and delicate organ that detects minimal changes in sound pressure. Damage to these hair cells due to loud noise (or even a single impulse) can lead to permanent hearing loss, though this is not usually as debilitating as it sounds. Generally speaking, anything above 85 decibels is considered harmful to the ears, and workers must wear appropriate protection.
Welding, plasma cutting, and similar processes often produce much higher levels of noise than this (e.g., hammering and guillotines can generate up to 105 decibels, grinding hard metal can reach over 110 decibels, and air carbon arc gouging can reach up to 120 decibels).
Employers should offer a range of types of ear protection that workers can choose from, keeping in mind that the kind of protector they prefer will likely influence whether or not they wear it. Molded plugs that fit comfortably in the ear are better than ones that are too bulky, especially if workers must remove and reinsert them many times during the day.
