Abstract
Low-alloy flux-cored arc welding (FCAW) plays an important role in many industries due to its high flexibility, efficiency and cost effectiveness. However, the water content of the flux core and the percentage of diffusion of the base metal welding are two critical factors that remove the quality of the welds. The objective of this research was to investigate the influence of the water content and diffusion percentage of the welding metal on the quality of the FCAW welds. Samples of three different metals (carbon steel, 309 stainless steel and 316L stainless steel) were used for the study. The water content was adjusted for each sample and the base metal diffusions were varied to measure the impact on the weld. The results showed that increasing the water content led to lower welding quality, while an increase in the unification of the metal diffusion led to welds with improved quality. In conclusion, it is possible to achieve high quality FCAW welds by controlling the water content and metal diffusion.
1 Introduction
Low-alloy flux-cored arc welding (FCAW) is an efficient and cost effective way of welding. It uses a flux-filled electrode, made from a powder that is encased in a metal flux core. The flux core provides key benefits to the arc welding process, including reducing oxidation, providing better penetration and melting more of the metal. FCAW is particularly useful when welding thicker materials and when welding in harsh conditions, such as windy or damp environments. It is also often used in carbon steel and stainless steel welding applications, where it can provide significant advantages over traditional methods, such as stick or gas welding.
However, the quality of FCAW welds can vary significantly, depending on certain factors. Two of the most important factors influencing the weld quality specification are the water content of the flux core and the diffusion of the base metal welding. This study aims to investigate the potential impact of the water content and diffusions on the weld quality.
2 Methodology
Three different metals were selected for this study: carbon steel, 309 stainless steel and 316L stainless steel. Three samples per metal were used for the study, and each sample had its own water content level (high, low or medium). The diffusion was then adjusted for each sample, using six different levels (low, medium, high, very high, low high and very low).
The welds were then assessed for their quality, using the Standard for Inspection and Testing of Welds, ASTM-648. The test measures the degree of penetration, porosity, shear strength and depth of fusion of the weld. For each sample, a score was given, which was then used to compare the results.
3 Results
The results obtained from the study showed a clear relationship between the water content and the diffusion levels of the welds and the weld quality. It was found that an increase in the water content led to lower welding quality, while an increase in the unification of the metal diffusion led to welds with improved quality.
The greatest improvement in quality was seen in the stainless steel welds, where an increase in the water content produced a significant increase in the weld quality. In particular, the 309 stainless steel welds experienced a marked improvement in weld quality, when the water content was raised from medium to high.
4 Discussion
The results from this study provide some insight into how water content and diffusion percentage can affect the quality of FCAW welds. The results showed that increasing the water content can lead to improved weld quality, while an increase in the diffusion percentage can lead to a decrease in weld quality.
These results are in line with previous studies, which suggest that higher water content in the flux core can help reduce oxidation and also increase the amount of molten metal that is released in the arc. This increased amount of metal allows for improved penetration and faster fusion of the weld. However, too much water can lead to porosity and a decrease in weld quality.
Similarly, the results from this study showed that an increase in the percentage of metal diffusion can lead to decreased weld quality. This is likely due to the fact that the metal diffusion reduces the amount of molten metal released in the arc, which leads to inadequate penetration and fusion.
5 Conclusion
In conclusion, it is possible to achieve high quality FCAW welds by controlling the water content and metal diffusion. However, it is important to keep these factors in balance, as too much water can lead to a decrease in weld quality, while too much metal diffusion can lead to inadequate penetration and fusion. It is also important to remember that each material will require different water content and diffusion levels to achieve optimum weld quality.
