With the development of the petroleum industry in China, galvanized steel pipes are increasingly used as pipelines for transporting crude oil in oil fields. Therefore, zinc coatings undergo a certain degree of corrosion in crude oil containing hydrogen sulfide and in aerated stratified water containing hydrogen sulfide. As a result, the corrosion resistance of galvanized steel pipes under oil production conditions is quite limited. However, it is also reported that in groundwater containing 240-400 mg/L of hydrogen sulfide near oil wells, the lifespan of galvanized steel pipes is 5 to 6 times longer than that of ungalvanized pipes.
If galvanized steel pipes are annealed at a temperature of 500 to 550°C for ten minutes, the pure zinc layer can be transformed into an iron-zinc alloy layer. This alloyed galvanized steel pipe exhibits significantly improved corrosion resistance compared to non-alloyed galvanized steel pipes.
