Why are chromium-containing steels used for oil-industry tubing?

Chromium-containing steels are utilized for tubing in the oil industry primarily because they offer increased resistance to corrosion and oxidation.1

Specifically, steels containing between 6 and 10 percent chromium are employed for this purpose. The addition of chromium to steel is highly effective because, at sufficient concentrations, it facilitates the formation of a protective oxide film on the metal's surface when exposed to air. Beyond enhancing corrosion resistance, chromium is also added to steel to improve its hardenability, wear resistance, and strength at high temperatures.123