API SPEC 5LD CRA Clad or Lined Steel Pipe

This specification covers seamless and welded clad steel line pipe and lined steel line pipe with enhanced corrosion-resistant properties suitable for use in pipeline transportation systems in the petroleum and natural gas industries. The clad and lined steel line pipe specified herein is composed of a carbon steel backing or base material outside (in some cases inside and/or outside) and a corrosion-resistant alloy (CRA) layer or lining inside of the pipe. The base material conforms to API 5L (45th Ed.), product specification level (PSL) 2 and applicable annex(es), except as modified herein. Grades of base material covered by this specification include X42, X46, X52, X56, X60, X65, X70, X80, and grades intermediate to these. Grades of the CRA layer are LC 1812, 2205, 2506, 2242, 2262, unified numbering system (UNS) S31703, UNS N08904, UNS N10276, Alloy 31 (UNS N08031), Alloy 59 (UNS N06059), Alloy 254 SMO-11 (UNS S31254), Alloy 400 (UNS N04400), AL6NX (UNS N08367), and EN 1.4529 (UNS N08926). Other grades are subject to agreement between the purchaser and the manufacturer. The delivered product usually has square ends, but other special ends may be furnished by agreement between the purchaser and manufacturer. Included are nominal pipe sizes (NPS) 25 mm (1 in.) through 2134 mm (84 in.). Sizes greater than 2134 mm (84 in.) are outside of the range of API 5L (45th Ed.) but may be supplied up to 2500 mm (100 in.) by agreement, including requirements for materials.

Longitudinal or helical seam CRA clad steel pipe:

Use hot rolling metallurgy composite plate or coil as material, modern advanced pipe-making technology (UOE, JCOE, COE and SAWH) to forming, SAWL or SAWH, and TIG etc. combined automatic welding process to complete welding. The welding quality is stable, and the product size accuracy is high. The composite plate or coil is manufactured by hot rolling technology, which can achieve metallurgical bonding of the atom between corrosion-resistant clad and the backing layer, the binding force reaches above 200MPa, the binding area rate can reach above 99.9%, and the performance is stable and reliable. The clad can meet the corrosion-resistant specific performance requirements, and the backing layer can meet the strength and rigidity condition the structure required.

Seamless or welded Lined steel pipe:

Seamless or welded carbon steel pipe as the outer backing layer, and corrosion-resistant alloy pipe as the inner corrosion layer, using the limit elasticity hydraulic composite method innovated independently by the company achieves the composite between the inner and outer pipe and forms the mechanical liner pipe. Through the composite technology, the optimal composite effect of mechanical liner can be achieved, and the shear stress between inside and outside metal layer can reach 2.0MPa (the relative standard requires 0.2-0.5MPa). Meanwhile, we develops specially the pipe ends automatic overlaying technology and NC machine tools specialized for beveling, which can process complex shape bevels such as U-bevel, and guarantees the conformity of pipe mouth diameter and bevel size, so as to operate pipe jointing on site.

PRODUCT MATERIALS of CRA clad pipes or lined steel pipes

1.BACKING MATERIALS:

Q235B, Q345B, Q245R, Q345R, 16MnDR, L245～L485 (API 5L Gr.B, X42～X70), and other backing materials may be used according to user’s requirement.

2.CRA GRADES:

S30408 (TP304), S30403 (TP304L), S31608 (TP316), S31603 (TP316L), S32168 (TP321), S31803 (LC2205), S31260 (LC2506), N06625 (ASTM B443 625), N08825 (ASTM B424 825), and other corrosion-resistant cladding materials may be used according to user’s requirement.

CRA LINED STEEL PIPE SIZE TABLE

Significant cost savings on capital expenditure for production flow lines were achieved by the use of corrosion-resistant alloy (CRA) lined pipe, instead of solid CRA and metallurgically clad pipe options.
Presented here are the materials philosophy of the project team and the rationale for selecting bi-metal-lined pipe along with a description of the manufacture, fabrication, and installation of the flow lines.

Clad pipe
Use of CRA-clad steel line pipe is familiar to the offshore oil and gas industry. In a clad line pipe, the corrosion-resistant alloy forms a complete barrier layer on the internal surface of carbon or low-alloy steel pipe (usually referred to as the “backing steel”). In general, use of clad or bi-metal-lined pipe allows the economic use of expensive CRA materials.
Corrosion resistance to the process environment is provided by the internal CRA clad layer, typically 2.5-3.0 mm thick, while the less expensive carbon backing steel provides the line pipe with the required strength and toughness to maintain the mechanical integrity.
Clad line pipe can be manufactured by various techniques that include the forming and welding of hot roll bonded plate, hot co-extrusion, weld overlay, and manufacture of lined pipe. The details of the various methods of manufacture are well documented.1, 2 For Bruce Phase II development, manufacturing of the CRA-lined pipe was by a process involving hydraulic expansion of a CRA liner pipe inside a carbon-steel outer pipe. The finished product is supplied as bi-metal-lined pipe.
A more-detailed description of the manufacturing process occurs presently.
Manufacture of bi-metal-lined pipe is based upon use of traditional manufacturing routes for the primary materials, carbon-steel outer pipe, and CRA liner pipe.