SSAW Steel Pipe, also known as spiral submerged arc welded steel pipe, may encounter the following problems during use:

Welding defects

Weld porosity: During the welding process, if the groove is not cleaned thoroughly, the welding rod is damp, or the welding parameters are improper, it may cause porosity in the weld. Pores can reduce the density of welds, making steel pipes prone to leakage under pressure, affecting their sealing and strength.

Slag inclusion: During welding, the slag fails to fully surface the weld seam and remains in the weld seam, forming slag inclusions. Slag inclusion can weaken the effective cross-sectional area of the weld, causing stress concentration and reducing the load-bearing capacity of the weld. In severe cases, it may lead to weld cracking.

Lack of penetration: Improper groove angle, insufficient gap between joints, low welding current, or too fast welding speed may all cause incomplete fusion at the root or between layers of the weld, resulting in a lack of penetration defect. Lack of penetration can reduce the mechanical properties of the weld seam, and it is easy to produce cracks at the lack of penetration during use, leading to safety accidents.

Corrosion issue

External corrosion: If SSAW steel pipes are exposed to corrosive environments such as humidity, acidity, or alkalinity for a long time, chemical reactions will occur on the surface of the steel pipes, gradually leading to corrosion. External corrosion can cause thinning of the steel pipe wall thickness, reducing its load-bearing capacity and service life, and in severe cases, may lead to perforation and leakage of the steel pipe.

Internal corrosion: When transporting corrosive media, the chemical components in the media will react with the inner wall of the steel pipe, causing internal corrosion. Internal corrosion not only affects the quality of medium transportation, but may also cause pipeline blockage, affect normal production operation, and even lead to safety accidents.

Wear and tear issues

Medium wear: When SSAW steel pipes are used to transport media containing solid particles, the particles will cause erosion and wear on the inner wall of the steel pipe during the flow process. Long term wear can cause the inner wall of the steel pipe to become thinner, reducing its strength and corrosion resistance, and in severe cases, may lead to perforation and leakage of the steel pipe.

Mechanical wear: During installation, maintenance, or contact with other objects, the surface of steel pipes may experience mechanical wear. Mechanical wear can damage the anti-corrosion layer of steel pipes, exposing them to the external environment, accelerating the corrosion process, and also reducing the overall strength of the steel pipes.

Deformation issue

Ellipticity deformation: SSAW steel pipes may undergo ellipticity deformation during transportation, loading and unloading, or installation if subjected to external compression or collision. Ellipticity deformation can affect the connection and sealing performance of pipelines, increase stress concentration in pipeline systems, and reduce the service life of pipelines.

Bending deformation: During the laying process of steel pipes, if the foundation settles unevenly, is affected by lateral forces or temperature changes, etc., bending deformation may occur. Bending deformation can change the stress state of steel pipes, increase the stress level of pipelines, and easily lead to pipeline rupture.

Stress concentration problem

Welding stress concentration: During the welding process, welding stress is generated in the weld seam and its surrounding areas due to the cooling shrinkage of the weld metal. If the welding stress is too high, it will cause cracks in the weld seam, reducing the strength and toughness of the weld seam.

Geometric stress concentration: During the manufacturing process of steel pipes, if there are geometric defects such as excessive weld seam height, undercutting, and misalignment, stress concentration will occur in these areas. Stress concentration can make steel pipes more prone to fatigue failure and brittle fracture during use.

Leakage issue

Sealing failure: Aging, damage, or improper installation of sealing gaskets at pipeline connections can lead to sealing failure, resulting in medium leakage. Leakage not only causes resource waste and environmental pollution, but may also lead to safety accidents.

Weld seam leakage: Defects such as porosity, slag inclusion, and incomplete penetration in the weld seam, or cracking due to corrosion, stress, and other factors during use, can all lead to weld seam leakage.

In addition to the above issues, SSAW steel pipes may also encounter the following problems during use:

Problems caused by material defects

Unqualified chemical composition: If the chemical composition of the steel pipe does not meet the standard requirements, such as excessive content of carbon, sulfur, phosphorus and other elements, it will affect the mechanical properties and corrosion resistance of the steel pipe. For example, excessive carbon content can increase the hardness of steel pipes, but reduce their toughness and make them prone to brittle fracture.

Uneven metallographic structure: In the production process of steel pipes, improper heat treatment may lead to uneven metallographic structure, such as uneven distribution of pearlite and ferrite. This will cause anisotropy in the mechanical properties of steel pipes, reducing their overall strength and reliability, and making them prone to defects such as cracks in weak tissue areas during use.

Problems caused by environmental factors

Effect of temperature changes: When used in high temperature environments, the strength of SSAW steel pipes will decrease, and creep phenomenon may occur, that is, the material slowly undergoes plastic deformation under long-term high temperature and constant stress. In low-temperature environments, the toughness of steel pipes decreases, becoming brittle and hard, and prone to brittle fracture.

The impact of ultraviolet radiation: If SSAW steel pipes are exposed to outdoor sunlight for a long time, ultraviolet radiation will cause the anti-corrosion coating on the surface of the steel pipe to age, crack, and peel off, thereby losing its protective effect on the steel pipe and accelerating the corrosion process of the steel pipe.

Problems caused by poor maintenance and management

Lack of regular testing: SSAW steel pipes in use are not regularly inspected and evaluated, making it difficult to detect potential problems such as corrosion, wear, deformation, etc. in a timely manner. Once these problems develop to a serious level, they may lead to sudden failure of the steel pipes and cause safety accidents.

Improper maintenance: When repairing steel pipes, if the maintenance methods used are incorrect, the quality of the repair materials is not qualified, or the repair process does not meet the requirements, it may further deteriorate the performance of the steel pipes and even produce new defects. For example, during the repair welding process, if the weld seam is not properly preheated and post heat treated, it is easy to produce welding cracks.

External force damage problem

Natural disasters such as earthquakes: In earthquake prone areas, strong earthquakes may cause serious damage to SSAW steel pipes, such as pipeline displacement and fracture. The inertial force and foundation deformation generated by earthquakes can exert enormous stress on steel pipes, exceeding their bearing capacity and causing pipeline system failure.

Man made damage: In some construction sites or other places, SSAW steel pipes may be damaged due to improper construction, human error, and other reasons. For example, accidentally breaking underground steel pipes during excavation operations, or colliding with steel pipes on the ground while carrying heavy objects, can cause damage to the steel pipes and affect their normal use.

Abnormal pressure issue

Overpressure operation: If SSAW steel pipes are subjected to pressure exceeding their design pressure during use, it will cause excessive deformation and stress in the pipes, leading to a decrease in their strength and even rupture. Overpressure operation may be caused by operational errors, process changes, or pressure control system failures.

Pressure fluctuations: Frequent pressure fluctuations can subject steel pipes to alternating stress, which can easily lead to fatigue failure. Especially in stress concentrated areas such as bends and tees in pipelines, fatigue cracks are more likely to occur and propagate, ultimately leading to pipeline leakage or fracture.