155 Welding Safety: Basic

Electric Arc Welding and Cutting

Arc welding is the process in which fusion is produced by heating with an electric arc that is generated between an electrode and the surface of the base metal.

Arc cutting is done when metals are cut or removed by melting with the heat of an arc between an electrode and base metal.

In electric welding, electrodes form a part of the electrical circuit. In gas tungsten arc welding, electrodes melt off and are a source of the filler metal supply.

• Solid Electrodes - These electrodes are consumable (composed of steel, copper, aluminum, various alloys, and other metals) or non-consumable (primarily tungsten). They produce fewer fumes compared with flux-cored wire or coated electrodes.
• Covered and Coated Electrodes - These are the largest group of electrodes used in welding. The covering provides the flux from the weld. Major metals from the coatings include fluoride, nickel, iron, chromium, manganese, copper, and molybdenum.

Overexposure to these substances can cause injury and illness over the long-term.

For more information on arc welding, read Safe Arc Welding by Lincoln Electric.

Brazing

Brazing is a welding process using non-ferrous filler alloys that do not contain iron or steel and have a melting point above 840°F but below that of the base metal. Brazing is also called "Hard Soldering" or "Silver Soldering."

Brazing is the only welding process in which melting the base metal is unnecessary for coalescence. Click here for more information on brazing alloys.

Soldering

Soldering is a joining process using non-ferrous filler alloys. Soft soldering uses alloys that melt between 190°F to 840°F and is used in electronics, plumbing, and joining sheet metal parts. Soldering is not considered a welding process. Lead and tin are common alloys used in soldering; however, there are also less common lead-free solder alloys used to decrease environmental impacts.

Knowledge Check Choose the best answer for the question.