There are some common considerations for the construction process of LSAW (straight seam submerged arc welding) steel pipes in different applications, and there are also special points in different scenarios. The following will introduce them to you from the aspects of pipeline laying, steel structure construction, mechanical manufacturing, etc.:

Pipe laying

Preparation before construction

Carefully inspect the quality of the steel pipe, including whether there are any defects in appearance and whether the dimensions meet the requirements. At the same time, check the quality certification documents of the steel pipe to ensure that it meets the engineering usage standards.

According to the construction drawings and the actual situation on site, plan the direction, slope, and connection method of the pipeline to ensure that the pipeline laying meets the design requirements and relevant specifications.

Steel pipe lifting and stacking

Suitable lifting equipment such as cranes should be used, and specialized lifting devices such as nylon slings or specialized pipe cranes should be used during the lifting process to avoid scratching or damaging the surface of the steel pipe.

When stacking steel pipes, a flat and solid site should be selected. Steel pipes should be stacked in layers, with wooden pads separating each layer to prevent them from rolling and colliding with each other.

Excavation and Treatment of Pipe Trenches

Excavate the pipe trench according to the design requirements. The depth and width of the trench should comply with the specifications, and the bottom of the trench should be flat to avoid sharp objects such as stones, which may damage the steel pipe.

Necessary drainage treatment shall be carried out on the pipe trench to prevent water accumulation in the trench from soaking the steel pipe, which may affect the anti-corrosion performance and stability of the steel pipe.

Pipe installation

During the installation process, it is necessary to ensure the accuracy of the steel pipe alignment, control the misalignment and gap, and ensure the quality of the weld seam. Suitable welding processes and parameters should be adopted, and welding personnel should have corresponding qualifications and experience. After welding is completed, non-destructive testing of the weld seam should be carried out in a timely manner.

When installing pipelines, strong coupling should be avoided to prevent large stresses from being generated inside the pipeline, which may affect its normal use. At the same time, attention should be paid to the issue of thermal compensation in pipelines, and compensators should be set up reasonably based on factors such as pipeline material, length, and usage environment.

Corrosion prevention and insulation

Steel pipes usually require anti-corrosion treatment before laying, such as using anti-corrosion coatings or anti-corrosion tapes. During construction, it is necessary to ensure the rust removal quality of the steel pipe surface to meet the design requirements for rust removal grade, and then carry out the construction of the anti-corrosion layer according to the prescribed process to ensure that the thickness and adhesion of the anti-corrosion layer meet the requirements.

For pipelines with insulation requirements, insulation layer installation should be carried out after anti-corrosion construction is completed. The selection of insulation materials should be determined according to the operating temperature and environmental conditions of the pipeline. During the installation process, attention should be paid to the integrity and sealing of the insulation layer.

Backfilling and compaction

After the pipeline installation and inspection are qualified, backfilling should be carried out. The backfill soil should meet the requirements and should not contain stones, garbage, or other debris. Backfilling should be carried out in layers, and the thickness of each layer should not be too large. Suitable compaction equipment should be used for compaction to ensure that the compactness of the backfill soil meets the requirements of the specifications.

Steel structure building

Component processing

According to the design requirements, perform cutting, bending, drilling and other processing operations on LSAW Steel Pipes. During the processing, attention should be paid to controlling the machining accuracy, ensuring that the size and shape of the components meet the design requirements, and avoiding difficulties in component installation or affecting the stability of the structure due to machining errors.

For components that require welding connections, a reasonable welding process should be developed to control welding deformation and welding stress. During the welding process, appropriate measures such as preheating and post heating should be taken to prevent defects such as welding cracks.

Steel structure installation

Before installation, the foundation should be inspected and accepted to ensure that its flatness, elevation, and the position of the anchor bolts meet the requirements. During the installation of steel structures, suitable lifting equipment should be used to lift the components in the designed installation sequence, ensuring the installation accuracy and connection quality of the components.

During the installation process, attention should be paid to the protection of steel pipe components to avoid collision, deformation, or damage to the surface anti-corrosion layer. For open-air steel structures, it is necessary to carry out rust prevention and fire prevention treatment, select suitable rust proof paint and fireproof coating according to environmental conditions, and carry out construction according to the prescribed process.

Quality inspection and acceptance

After the construction is completed, a comprehensive quality inspection of the steel structure should be carried out, including the dimensions of the components, the quality of the welds, the quality of the coating, and the overall stability of the structure. Using non-destructive testing technology to inspect welds, ensuring that the quality of welds meets design and specification requirements.

Acceptance shall be carried out in accordance with relevant standards and specifications, and only after passing the acceptance can it be put into use. During use, it is necessary to regularly inspect and maintain the steel structure to promptly identify and address any potential issues.

Machinery manufacturing

Accuracy control

In mechanical manufacturing, LSAW steel pipes are usually used as raw materials for mechanical components, requiring high dimensional accuracy. During the processing, high-precision processing equipment and advanced processing technology should be used to strictly control the dimensional parameters such as outer diameter, wall thickness, and straightness of the steel pipe, ensuring that the assembly requirements of mechanical components are met.

For steel pipes that require surface treatment, such as grinding, polishing, etc., it is necessary to ensure that the surface roughness and surface hardness meet the design requirements to improve the performance and service life of mechanical components.

Welding and assembly

When steel pipes need to be welded and assembled with other components, appropriate welding materials and welding processes should be selected based on the material and usage requirements of the components. During the welding process, the welding quality should be strictly controlled to avoid defects such as porosity, slag inclusion, and cracks, ensuring the strength and sealing of the welded joint.

During the assembly process, steel pipes and other components should be assembled according to the design requirements to ensure assembly accuracy and fit clearance. For some mechanical components with special requirements, such as ensuring coaxiality, perpendicularity, etc., specialized assembly fixtures and testing equipment should be used for assembly and testing.

performance testing

After the manufacturing is completed, performance tests such as strength testing, sealing testing, fatigue testing, etc. should be conducted on mechanical components using LSAW steel pipes to verify whether the mechanical components meet the design requirements and usage performance.

Based on the test results, necessary adjustments and improvements will be made to the mechanical components to ensure their reliable and stable performance. At the same time, it is necessary to record and analyze the test data to provide reference for subsequent production and improvement.

The above are some construction process precautions for LSAW steel pipes in different applications. In actual construction, detailed construction plans and quality control measures need to be developed based on specific engineering requirements, relevant standards and specifications, and the actual situation on site to ensure project quality and safety.