Composition and Application Range of API 5L X65 Steel
API 5L X65 is an important grade of high-strength pipeline steel, offering higher strength than X60. It is widely used in high-pressure, long-distance transmission systems. With excellent strength, toughness, and corrosion resistance, X65 performs exceptionally well in demanding engineering environments.
In terms of composition, X65 maintains carbon content below 0.25% to ensure ductility and weldability. Higher manganese levels significantly enhance strength and impact resistance, while silicon improves microstructure uniformity. Phosphorus and sulfur are strictly limited to prevent cracking under high-pressure service. Some X65 steels also contain micro-alloying elements such as vanadium, niobium, or titanium to further improve performance.
X65 is commonly used in high-pressure oil and gas pipelines, cross-border natural gas projects, and subsea transmission systems. It is especially suitable for projects requiring long-distance transmission, high strength, and operation under harsh climatic conditions. With its strong load-bearing capacity and reliability, X65 has become one of the key materials in the international energy transmission industry.