The maintenance requirements for LSAW (submerged arc welding) steel pipes in different applications may vary due to factors such as working environment and conveying medium. The following are some common maintenance requirements for application scenarios:

Long distance onshore pipelines

External anti-corrosion coating maintenance: Regularly inspect the external anti-corrosion coating of the pipeline. If any damage, peeling or aging of the coating is found, it should be repaired or repainted in a timely manner. For pipelines crossing special areas such as swamps, saline alkali land, etc., anti-corrosion monitoring should be strengthened, and the detection frequency can be increased.

Cathodic protection system testing: Regularly test the cathodic protection potential to ensure that the protection potential is within a reasonable range (generally between -0.85V and -1.2V). Check whether the cathodic protection facilities such as anode ground bed and test pile are intact, and repair or replace them in a timely manner if they are damaged.

Pipeline route inspection: Regularly inspect the pipeline route to check for any ground subsidence, exposed pipelines, surrounding construction activities, or other situations that may affect pipeline safety. For areas prone to natural disasters such as floods and mudslides, protective measures should be taken before the disaster prone season, such as reinforcing pipeline foundations and setting up retaining walls.

Ocean pipeline

Coating and anti-corrosion system maintenance: Due to the strong corrosiveness of the marine environment, it is necessary to regularly inspect the integrity and anti-corrosion performance of the external coating of the pipeline. Use underwater inspection equipment, such as remotely operated vehicles (ROVs), to check for damage, bulges, and other issues with the coating. For damaged areas, timely repair should be carried out, while considering the use of high-performance anti-corrosion coatings and sacrificial anode protection systems suitable for marine environments.

Monitoring of erosion and corrosion: Pay attention to the flow velocity and direction of seawater around the pipeline, as well as changes in seabed topography, as these factors may cause pipeline erosion and corrosion. Regularly measure the wall thickness of pipelines, especially in areas prone to erosion, such as pipe bends and tees. If the wall thickness is found to have decreased beyond the specified value, timely repair or replacement measures should be taken.

Marine organism attachment cleaning: Marine organism attachment can affect the heat dissipation and anti-corrosion performance of pipelines. Regular application of biocides or physical cleaning methods can be used to remove shellfish, algae, and other organisms on the surface of pipelines. However, attention should be paid to the impact of the use of biocides on the marine environment and relevant environmental regulations should be followed.

Acidic environment (including hydrogen sulfide)

Maintenance of sulfur resistant coating: Use specialized sulfur resistant coating, regularly check the integrity of the coating, and prevent acidic media from penetrating the surface of the steel pipe. If defects such as pinholes and cracks are found in the coating, immediate repair should be carried out to ensure the protective performance of the coating.

Stress corrosion cracking prevention: Control the operating stress of pipelines to avoid stress concentration. Perform regular non-destructive testing on pipelines, such as ultrasonic testing, magnetic particle testing, etc., with a focus on inspecting welded joints, bends, and other parts to promptly detect and address potential stress corrosion cracking. At the same time, it is necessary to strictly control the water content and hydrogen sulfide content in the conveying medium to prevent it from forming a corrosive environment inside the pipeline.

Material inspection and upgrading: Regularly inspect the steel pipe material based on its service life and corrosion condition to evaluate its sulfur resistance performance. For pipelines with long service life or severe corrosion, material upgrades or replacements should be considered to ensure the safe operation of the pipeline in acidic environments.

low-temperature environment

Anti brittleness measures: Use steel with good low-temperature toughness to manufacture LSAW Steel Pipes. When operating in low-temperature environments, it is important to avoid severe impacts or vibrations on the pipeline to prevent steel from becoming brittle and breaking. Regularly conduct low-temperature performance testing on pipelines, such as impact testing, to evaluate the changes in low-temperature toughness of steel.

Maintenance of insulation and heat tracing system: Check whether the insulation layer of the pipeline is intact. If there is any damage or moisture, replace or repair the insulation material in a timely manner to ensure the insulation effect. For pipelines using a heat tracing system, the operation of the heat tracing equipment should be regularly checked to ensure that the heat tracing temperature is stable within the specified range and to prevent the medium inside the pipeline from freezing.

Drainage and de icing: Install drainage devices at the low points of the pipeline to regularly drain condensed water from the pipeline, preventing water accumulation and freezing that could cause damage to the pipeline. For pipelines exposed outdoors, it is necessary to promptly remove snow and ice on the surface of the pipeline in winter to avoid increasing the load on the pipeline.

Urban gas transmission

Appearance inspection and leakage detection: Regularly inspect the appearance of pipelines to check for rust, deformation, and other conditions. At the same time, professional gas leak detection equipment, such as gas leak detectors, is used to detect pipeline interfaces, valves, and other parts, and timely detect and deal with leakage points. For buried pipelines, the presence of leaks can be determined by regularly monitoring the gas concentration in the soil.

Safety distance and protection: Ensure sufficient safety distance around the pipeline to avoid unauthorized construction and excavation activities above or near the pipeline. Set up clear warning signs along the pipeline to remind surrounding personnel to pay attention to protecting pipeline safety. For pipelines crossing special areas such as roads and rivers, protective measures should be strengthened, such as setting up sleeves, warning posts, etc.

Internal cleaning and impurity removal: Regularly clean the gas pipeline to remove impurities, rust, etc. inside the pipeline, preventing them from causing corrosion and blockage to the pipeline. At the same time, it is necessary to control the water and dust content in the gas to avoid the formation of liquid and dust accumulation in the pipeline, which may affect the transportation efficiency and safety of the pipeline.

High pressure rich gas transportation

Pressure monitoring and control: Install high-precision pressure monitoring equipment to monitor pressure changes in the pipeline in real time. Strictly control the operating pressure of the pipeline, avoid overpressure operation, and prevent pipeline rupture or seal failure caused by excessive pressure. At the same time, it is necessary to develop a reasonable pressure regulation plan and adjust the pressure in a timely manner according to the delivery volume and user needs.

Temperament testing and purification: Regularly conduct temperament testing on the transported rich gas, analyzing its composition and impurity content. Ensure that the rich gas undergoes strict purification treatment to remove acidic gases, moisture, solid impurities, etc., to prevent these substances from causing corrosion and wear to the pipeline. Regular maintenance and overhaul are required for purification equipment to ensure its normal operation.

Pipeline deformation monitoring: Due to the high pressure on high-pressure rich gas transmission pipelines, deformation is prone to occur. Adopting pipeline deformation monitoring technology, such as fiber optic grating monitoring system, intelligent pipe cleaner, etc., to regularly monitor the deformation of pipelines. When abnormal deformation is found in the pipeline, the cause should be analyzed in a timely manner and corresponding measures should be taken, such as adjusting operating parameters, repairing the pipeline, etc.