The production process of API 5L X52 oil welded pipe mainly includes the following steps:
Raw material preparation:
Purchase: Select steel plates or steel strips that meet the API 5L standard as raw materials. The chemical composition, mechanical properties and other indicators of these materials must meet the requirements of the X52 level to ensure the quality of the welded pipes processed later.
Inspection: Strict quality inspection of the purchased raw materials, including dimension measurement, surface quality inspection, chemical composition analysis, mechanical property testing, etc. Only raw materials that pass the inspection can enter the next production link.
Steel plate pretreatment:
Uncoiling: Unroll the rolled steel plate or steel strip for subsequent processing.
Flattening: The flattened steel plate is flattened by the flattening machine to eliminate the curling stress of the steel plate, make the surface of the steel plate flat, and ensure the accuracy of subsequent processing.
End shearing and welding: Shear the ends of the steel plate to make its edges neat, and then weld the adjacent ends of the steel plate to form a continuous steel strip to prepare for the subsequent forming process.
Leveling and milling: Use an anvil press to level the steel plate to ensure the flatness of the steel plate; then use the milling machine to double-sided mill the two edges of the steel plate to achieve the required plate width, plate edge parallelism and groove shape.
Forming:
Spiral welded pipe forming (if spiral welding process is used):
The pre-treated steel strip is gradually bent into a spiral shape by a forming machine to form a tube. During the forming process, the feed speed, bending angle and other parameters of the steel strip must be strictly controlled to ensure that the shape and size of the tube meet the requirements.
A weld gap control device is used to ensure that the weld gap meets the welding requirements, so that the pipe diameter, misalignment and weld gap are strictly controlled.
Straight seam welded pipe forming (if straight seam welding process is used):
UOE forming: First, the steel plate is pre-bent, and then the edge pre-bending, U forming and O forming are completed in sequence on a special forming press to deform the steel plate into a round tube.
JCOE forming: After multiple step-by-step stamping on the JC0 forming machine, first half of the steel plate is pressed into a "J" shape, then the other half of the steel plate is pressed into a "J" shape to form a "C" shape, and finally pressure is applied from the middle to form an open "0" shaped tube blank.
RB forming: The steel plate is rolled and bent into shape, and then subsequent welding and other processes are carried out.
Welding:
Select welding method: According to the type and requirements of the welded pipe, select a suitable welding method, such as double-sided submerged arc welding (applicable to straight seam submerged arc welded pipes), high-frequency current welding (applicable to straight seam high-frequency welded pipes), etc. For API 5L X52 petroleum welded pipes, the welding process usually used needs to ensure the quality and strength of the weld, and can meet the requirements of harsh working conditions such as oil transportation.
Implementation of welding: During the welding process, the welding parameters, such as welding current, voltage, welding speed, welding temperature, etc., must be strictly controlled to ensure that the weld depth, weld width, welding strength, etc. meet the standard requirements. At the same time, the welding environment must be controlled to avoid external factors affecting the welding quality.
Weld seam treatment:
Removal of internal and external weld beads: After welding, use special equipment or tools to remove weld beads and burrs at the weld to make the weld surface smooth and flat, reducing the resistance and wear of the fluid when flowing in the pipeline.
Weld seam inspection: Perform visual inspection and non-destructive testing on the weld, such as ultrasonic flaw detection, radiographic flaw detection, etc., to check whether the weld has defects such as cracks, pores, slag inclusions, etc., to ensure the quality and sealing of the weld.
Subsequent processing:
Preliminary correction: Perform preliminary correction on the welded pipe after welding, adjust the straightness and roundness of the welded pipe to meet the size requirements.
Induction heat treatment: Perform induction heating treatment on the welded pipe to improve the metallographic structure of the weld and the pipe body, and improve the strength and toughness of the welded pipe.
Sizing and straightening: The outer diameter of the welded pipe is accurately controlled by the sizing machine to make its size meet the standard requirements; at the same time, the welded pipe is straightened to ensure the straightness of the welded pipe.
Eddy current detection: Use eddy current detection equipment to detect the welded pipe and check the defects on the surface and near the surface of the welded pipe, such as cracks, scratches, etc.
Quality inspection:
Hydraulic test: Perform hydraulic test on welded pipes to check the sealing and strength of welded pipes to ensure that there will be no leakage during use.
Pickling: Pickle the welded pipes to remove rust, oil and other impurities on the surface of the welded pipes to improve the surface quality of the welded pipes.
Final inspection: Perform a comprehensive inspection on the appearance, size, chemical composition, mechanical properties, etc. of the welded pipes to ensure that the quality of the welded pipes meets the API 5L standard and customer requirements.
Packaging and shipment: Pack the welded pipes that have passed the inspection, and use different packaging methods according to customer requirements, such as bundling, boxing, etc. After packaging, the welded pipes will be shipped to customers.
API 5L X52 PSL1 LSAW Carbon Steel tube
