Mechanical Lined Pipe Manufacturing Procedure Specification

This manufacturing procedure specification is prepared mainly with reference of API Spec 5LD (3rd edition) Specification for CRA Clad or Lined Steel Pipe, SY/T6623-2005 Specification for CRA Clad or Lined Steel Pipe, SY/T6855-2012 Bi-metal Line Steel Pipe for Natural Gas Line with H2S/CO2 ,relevant technical specifications and related standards home and abroad.
This document is made based on process parameters determined by company’s current equipment, accessory equipment, line-ups and heat treatment conditions. If the above conditions change, process parameters will change accordingly.
I: CRA Liner Verification – performed by Quality Control Dept.
Quality Certificate Review: The quality certificate shall contain the material, specification, heat treatment No., production No., date, main chemical composition and mechanical properties of the CRA Liner. Pipes without quality certificate cannot be used in production.
Appearance Inspection: Cracks, bubble, inclusion, scars and layers are not allowed to appear on the CRA Liner surface. If the CRA Liner is not polished, very few tiny scratches, indentations, roll marks and pits can exist, but its depth or height shall not exceed 0.5 mm.
Dimension Inspection: It is necessary to check the CRA Liner dimension piece by piece, including the outside diameter, wall thickness, out-of-roundness, straightness and length. Testing results shall conform to API Spec 5LC standard and technical specification requirements.
Chemical Composition Verification: Re-test one piece of pipe from every batch (pipes with the same heat treatment number are considered as one batch). Take samples from the pipe body as well as the welding seam. Sample position of pipe shall be at least 90°with that of the welding seam; chemical composition of pipe and welding seam shall conform to the requirements of API Spec 5LC and technical specifications.
Mechanical Properties Verification: Re-test one piece of pipe from every batch (pipes with the same heat treatment number are considered as one batch).Conduct pipe tensile strength test to pipe. Testing results shall conform to the requirements of API Spec 5LC and technical specifications.
Report Completion: Record all data of the re-test and complete the Raw Material Verification Report. Put the qualified pipes in storage and notify purchasing department in time about the disqualified pipes. It is forbidden to put the disqualified pipes into production.
II: Backing Pipe Verification – performed by Quality Control Dept.
Quality Certificate Review: The quality certificate shall contain the material, specification, heat treatment No., production No., date, main chemical composition and mechanical properties of the backing pipe. Pipes without quality certificate shall be used in production.
Appearance Inspection: Cracks, fold, rolling marks, separation layer and capillary crack. All these defects shall be moved out. Elimination depth shall not surpass the minus value of tolerance. The wall thickness at the cleaning point shall not be less than the allowed min figure of tolerance.
Dimension Inspection: It is necessary to check the backing pipe dimension piece by piece. Tolerances shall conform to API Spec 5L and technical specification and other relevant standards requirements.
Chemical Composition Verification: Re-test one piece of pipe from every batch (pipes with the same heat treatment number are considered as one batch). Chemical composition of pipe shall conform to the requirements of API Spec 5L.
Mechanical Properties Verification: Re-test one piece of pipe from every batch (pipes with the same heat treatment number are considered as one batch). Mechanical testing results shall conform to API Spec 5L requirements.
Report Completion: Record all data of the re-inspection and complete the Raw Material Verification Report. Put the qualified pipes in storage and notify purchasing department in time about the disqualified pipes. It is forbidden to put the disqualified pipes into production.
III: Welding Consumables Verification – performed by Quality Control Dept.
Quality Certificate Review: The quality certificate shall contain the material, specification, heat treatment No., production No., date, main chemical composition and mechanical properties of the CRA Liner. Welding wires without quality certificate shall not be used in production.
Chemical Composition Verification: Take sample of each size based on the heat treatment number to make melting chemical analysis. Chemical composition shall conform to relevant standard. Complete Raw Material Verification Report for qualified welding wires; notify purchasing department in time about the disqualified welding wires and never use the disqualified welding wire in production.
IV: Backing Pipe Inner Side Blasting – performed by Production Dept.
Backing Pipe Inner Side Blasting: Before assembling the backing pipe and CRA Liner, blasting shall be conducted. Remove the oxide skin and make the inner side free of covers like grease and sand grains before blasting. Remove the burr fin and kerfs by file. Surface cleanness shall reach ISO Sa2.5 sand blasting treatment level.
V: Backing Pipe and CRA Liner Assembly – performed by Production Dept.
Assembly: Assembly the backing pipe and CRA Liner after sand blasting. If the backing pipe is welded, actions shall be taken to avoid matching welding seams of backing pipe and CRA Liner together. Keep the assembly temperature and humidity proper for production requirements.
VI: Mechanical Pressing – performed by Production Dept.
Mechanical Pressing: Put the assembled backing pipe and CRA Liner into the mechanical pressing machine. Fix the diameter by mold and take the inner diameter as benchmark to conduct mechanical pressing. Make sure that the CRA Liner is free from the contamination of Cu, Sn and Fe ion.
Straightness Correction: After mechanical pressing, conduct the straightness correction and the straightness tolerance shall not exceed 0.2% of the pipe length.
End Cutting: Cut off the extra CRA Liner at both ends and make the ends even.
VII: End Welding – performed by Production Dept.
End Processing: Process the CRA Liner ends by lathe machine and measures the length.
If interest, welcome to contact us for more details.
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