Occupational HazardsOccupational Hazards

HUNDREDS OF THOUSANDS of people work in welding, cutting and brazing. It is estimated that welders compose 1 to 2% of the U.S. working population, including a significant segment of the aging workforce. According to OSHA’s Christine Petitti, the most commonly used welding processes are: 1) Flux-cored arc welding (FCAW). This process uses an arc between a continuous filler metal electrode and the weld pool. It also uses shielding gas from a flux contained within the tubular electrode, with or without additional shielding gas and without the application of pressure. 2) Gas metal arc welding (GMAW). Like FCAW, this process uses an arc between a continuous filler metal electrode and the weld pool. It uses shielding from an externally supplied gas and without the application of pressure. 3) Gas tungsten arc welding (GTAW). This process uses an arc between a tungsten electrode (nonconsumable) and the weld pool. It is used with a shielding gas and without pressure. 4) Shielded metal arc welding (SMAW). This process uses an arc between a covered electrode and the weld pool. It is used with shielding from the decomposition of the electrode covering without pressure and with filler metal from the electrode. 5) Submerged arc welding (SAW). This process uses an arc or arcs between a bare metal electrode or electrodes and the weld pool. A blanket of granular flux on the workpiece shields the arc and molten metal. It is used without pressure and with filler metal from the electrode. 6) Oxyacetylene welding (OAW). This process uses acetylene as the fuel gas. It is used without pressure. Petitti then identified the three most common cutting processes used in welding: 1) Oxygen cutting: This group of thermal cutting methods severs or removes metal by means of the chemical reaction between oxygen and the base metal at elevated temperatures. 2) Oxyacetylene cutting: This variation uses acetylene as the fuel gas. 3) Plasma arc cutting: This method uses a constricted arc and removes the molten metal with a high-velocity jet of ionized gas issued from the constricting orifice.