Introduction
Flux cored arc welding (FCAW) is a welding process which has become increasingly popular in recent years. It was first developed in the 1940s as an alternative to shielded metal arc welding (SMAW), which had been in use since the early 1900s. FCAW is a welding process in which a continuous flux-coated wire is fed into an electric arc, creating a molten weld pool and consequently, a fusion bond.
Flux cored arc welding is particularly useful in welding materials that are difficult to weld by other processes such as stainless steel, aluminum and nickel alloys. Compared to SMAW, FCAW provides a faster and cleaner weld with lower distortion and spatter. Additionally, FCAW uses self-shielding electrodes, meaning that no external shielding gas is required.
In addition to being efficient, FCAW is also economical and has the potential for automation. Automated welding systems can reduce manpower costs and increase productivity.
Recently, a type of FCAW has emerged as an alternative to SMAW: Oxy-acetylene FCAW. This process involves the use of oxy-acetylene gas in conjunction with a flux-cored consumable. The oxy-acetylene gas provides both a protective atmosphere, shielding the weld pool from oxidation, and a fuel source, powering the arc. Oxy-acetylene FCAW has the potential to replace SMAW in many applications that are either too difficult or too costly to join using SMAW.
In this paper, we will discuss the physical properties of oxy-acetylene FCAW alloy powders. We will analyze their microstructures and mechanical properties, and compare them to those of SMAW alloy powders to determine the advantages and disadvantages of oxy-acetylene FCAW compared to other welding processes.
Microstructure
The microstructures of oxy-acetylene FCAW alloy powders are similar to those of SMAW alloy powders. Both powders contain a variety of inclusions, such as grain boundaries, dispersoids and solidified particles of flux residue.
The grain boundaries, solidified particles of flux residue and dispersoids are both thermally stable, imparting improved thermal stability to the final weld.
Mechanical Properties
The mechanical properties of oxy-acetylene FCAW alloy powders are comparable to those of SMAW alloy powders. Both processes can produce welds with high strength and ductility and good impact toughness.
The microalloyed elements, such as niobium and vanadium, found in oxy-acetylene FCAW alloy powders act as fine grain and dispersoid strengthening agents, resulting in improved mechanical properties.
Advantages and Disadvantages
Oxy-acetylene FCAW offers several advantages over SMAW. It is faster, produces a cleaner weld with less spatter, requires no external shielding gas and is easier to automate. Additionally, oxy-acetylene FCAW alloy powders can be formulated to offer superior mechanical properties.
The main disadvantage of oxy-acetylene FCAW is its higher cost. Additionally, oxy-acetylene FCAW produces more welding fumes and higher welding currents than SMAW.
Conclusion
In conclusion, oxy-acetylene FCAW is a useful and cost-effective alternative to SMAW, capable of producing superior welds with excellent mechanical properties. Its use has the potential to reduce labour costs and increase productivity in many applications.
