1. Chemical composition
The carbon content of API 5L B is not much different from that of X65, but the manganese content is roughly within 1.2%, which helps to improve certain strength and toughness. The content of alloy elements such as nickel, chromium, and molybdenum is extremely small, and the overall composition is relatively simple. Impurity elements such as sulfur and phosphorus are limited to less than 0.030% to ensure basic quality.
The manganese content of API 5L X65 can reach about 1.65%, and it contains appropriate amounts of alloy elements such as chromium, nickel, and molybdenum. Through the synergistic effect of these alloy elements, the strength, toughness, and corrosion resistance of the pipe are significantly improved. Its alloy system is relatively complex and the content is higher than API 5L B.
2. Mechanical properties
The minimum yield strength of API 5L B is 241MPa, which determines its load-bearing capacity under lower pressure environments. The tensile strength is in the range of 415MPa - 655MPa, which can withstand a certain tensile force but is relatively limited.
API 5L X65 has a minimum yield strength of 450MPa, which can withstand high pressure and work stably in scenarios such as high-pressure oil and gas transportation. The tensile strength is usually 530MPa and above, with strong tensile resistance.
The elongation is about 19%, which is slightly lower than API 5L B. While ensuring high strength, it still retains a certain deformation capacity.
3. Manufacturing process
API 5L B mainly relies on the basic hot rolling process to shape the raw materials, and then cooperates with normalizing or stress relief heat treatment to adjust the internal structure. It has low requirements for equipment, short production process, high efficiency and low cost in large-scale production.
API 5L X65 uses controlled rolling technology to accurately control the deformation amount, temperature and other parameters of steel during rolling to refine the grains and improve strength.
The accelerated cooling process can enable the pipe to obtain an ideal structure at a specific cooling rate, and the quenching and tempering processes further optimize the material properties. These processes are complex and require high equipment precision, resulting in a long production cycle and increased costs.
4. Application Scenarios
API 5L B is mostly used in low-pressure, medium-temperature conventional pipeline systems, such as small-area heat collection systems for collecting and transmitting heat energy, urban gas distribution pipelines, which distribute gas from high-pressure trunk lines to various user areas, and some short-distance, low-pressure industrial raw material pipelines, which do not require strict strength.
API 5L X65 It is an ideal choice for high-pressure, high-temperature oil and gas transmission trunk lines. It can stably transport a large amount of oil and gas resources over long distances and withstand huge internal pressure and external environmental stress. For example, oil and gas pipelines face harsh conditions such as seawater corrosion, wave impact, and complex geological stress. The high strength and good toughness of X65 can ensure the safe operation of the pipeline.
API 5L PSL2 X60 Seamless tube
