## 4 Conclusions  
Using the linear polarization resistance (LPR) method and the work presented in this paper, we have been able to make repetitive measurements of the corrosion rate of API-5L-X65 QT steel--taking an average of at least three measurements per parameter. For each test condition, one parameter was varied, while all other parameters were kept constant. This level of detail is essential to assess the true effect of each parameter on the corrosion rate.  
Experimental data presented in this work indicates a complex relationship between pH level, temperature, salt concentration, flow velocity, and corrosion rate. For the majority of combinations of experimental parameters, one can observe a range of flow velocities where the corrosion rate reaches a quasi-steady state or exhibits a linear behavior. The complex behavior where the corrosion rate is best described by exponential functions is mostly observed for cases with pH = 5. For pH = 5, the exponential function, that fits the experimental data very well, has the form \(c_{r}=a+be^{-c_{r}}\) where \(c_{r}\) is the corrosion rate, \(v\) is the fluid velocity, and \(a\), \(b\), and \(c\) are the fitting constants. The majority of the experimental data, but not all, suggests that in the velocity range of 0.2 m/s to 0.8 m/s, the corrosion mechanism appears to be uniform corrosion, and erosion corrosion is not occurring. Near fluid velocity of 0.8 m/s, an increase in corrosion rate is observed in most cases but not all. Turbulence-induced erosion corrosion maybe occurring. The highest corrosion rate occurs at 40 \({}^{\circ}\)C and 3.5% salt concentration, and the corrosion rate is about 0.25 to 0.3 mm/yr.  
Figure 13: Corrosion rates at different temperatures for flow insensitive regions are fitted using Power-law.  
In this paper, we have also produced individual equations relating to the corrosion rate to a given parameter. In the future, it is our intention to look at the synergistic effects of changing two or more parameters at the same time and study their effects on the corrosion rate of oil pipelines. Eventually, this work will lead towards a predictive model of the corrosion rate in mild steel pipelines. Since API-5L-X65 material is widely used in the oil industry, the experimental data collected and published in this paper can be very useful to corrosion engineers working in the oil industry.  
[PERSON] conducted all the experimental testing, and wrote the first draft of this paper, [PERSON] was responsible for the design of the flow loop, supervision of this project and experimental data analysis, [PERSON] was the overall principle investigator of the research project that included this work, is the corresponding author, and was responsible for detailed review of this journal paper, and [PERSON] was responsible for experimental data analysis. All research members (the authors) met weekly and gave technical inputs/suggestions to the first author throughout the duration of this research project. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Khalifa University (KU) and we are grateful to the Chemistry Department of the Khalifa University for providing laboratory space for this project.  
Data sharing not applicable.  
The authors declare no conflict of interest.