Chapter 9 Gas Metal and Flux Cored Arc Welding
Learning Objectives
After studying this chapter, you will be able to:
The gas metal arc welding (GMAW) process uses a solid welding wire that is continuously fed into the weld pool. The welding wire is consumed and becomes the filler metal. Flux cored arc welding (FCAW) is very similar to gas metal arc welding. One big difference between GMAW and FCAW is that FCAW uses a welding wire with flux inside the wire. See Chapter 4 for an overview of these processes.
The growing popularity of GMAW is due to several factors. The continuous development and refinement of constant voltage arc power sources and wire feeders has made GMAW more effective to use. Welding using GMAW is easy to learn, especially if a welder has already learned to weld using a different process. GMAW equipment is relatively low in cost. Also, GMAW deposits more weld metal in lbs/hr (kg/hr) than the shielded metal arc and gas tungsten arc welding processes. The low purchase cost, the ability to weld continuously, and the ability to deposit weld metal faster, make GMAW an attractive choice for welding.
GMAW can be used to produce high-quality welds on most metals commonly used in manufacturing, including aluminum, magnesium, stainless steels, carbon and alloy steels, copper, and others. GMAW may also be performed easily in all welding positions.
FCAW is a very popular welding method. It has the advantages of both GMAW and SMAW. The advantages of GMAW include the ability to weld continuously, to deposit weld metal faster, and it is an easy process to learn. The advantages of SMAW include the addition of alloying and fluxing elements in the electrode. FCAW can be done with shielding gas. Gas-shielded FCAW is known as FCAW–G. FCAW can also be done without shielding gas. The flux cored electrode creates a protective atmosphere around the weld area. Self-shielded FCAW is known as FCAW–S.
Learning Objectives
After studying this chapter, you will be able to:
- Contrast the various GMAW metal transfer methods, considering arc characteristics, weld characteristics, and out-of-position welds.
- Select the proper arc welding machine, wire feeder, shielding gas, flow rate, contact tube, nozzle size, and welding wire type to produce an acceptable weld.
- Contrast the various types of shielding gases used for GMAW, and how they affect the shape and penetration of the completed welds.
- Contrast the self-shielded and gas-shielded methods of FCAW.
- Properly assemble and adjust all the equipment required to produce an acceptable weld using the GMAW and FCAW processes.
- Correctly prepare metals for welding.
- Weld using GMAW. Make acceptable welds on all types of joints in all positions using GMAW.
- Weld using FCAW. Make acceptable welds on all types of joints in the flat and horizontal positions using FCAW.
- Identify the potential safety hazards associated with the GMAW and FCAW processes in a working environment and describe ways of safely dealing with these hazards.
- Be able to pass a safety test on the proper use of the GMAW and FCAW processes.
The gas metal arc welding (GMAW) process uses a solid welding wire that is continuously fed into the weld pool. The welding wire is consumed and becomes the filler metal. Flux cored arc welding (FCAW) is very similar to gas metal arc welding. One big difference between GMAW and FCAW is that FCAW uses a welding wire with flux inside the wire. See Chapter 4 for an overview of these processes.
The growing popularity of GMAW is due to several factors. The continuous development and refinement of constant voltage arc power sources and wire feeders has made GMAW more effective to use. Welding using GMAW is easy to learn, especially if a welder has already learned to weld using a different process. GMAW equipment is relatively low in cost. Also, GMAW deposits more weld metal in lbs/hr (kg/hr) than the shielded metal arc and gas tungsten arc welding processes. The low purchase cost, the ability to weld continuously, and the ability to deposit weld metal faster, make GMAW an attractive choice for welding.
GMAW can be used to produce high-quality welds on most metals commonly used in manufacturing, including aluminum, magnesium, stainless steels, carbon and alloy steels, copper, and others. GMAW may also be performed easily in all welding positions.
FCAW is a very popular welding method. It has the advantages of both GMAW and SMAW. The advantages of GMAW include the ability to weld continuously, to deposit weld metal faster, and it is an easy process to learn. The advantages of SMAW include the addition of alloying and fluxing elements in the electrode. FCAW can be done with shielding gas. Gas-shielded FCAW is known as FCAW–G. FCAW can also be done without shielding gas. The flux cored electrode creates a protective atmosphere around the weld area. Self-shielded FCAW is known as FCAW–S.