SEAMLESS METALLURGICAL BONDED CLAD PIPE & · PDF fileCOMPANY PHILOSOPHY 4 SX-CLAD SCHULZ GROUP OF COMPANIES SX-Clad - Metallurgical Bonded Seamless Clad Pipe A variety of techniques

SEAMLESS METALLURGICAL BONDED CLAD PIPE & FITTINGS

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SCHULZ XTRUDED PRODUCTS

SCHULZ GROUP OF COMPANIES WWW.WSCHULZ.COM

Schulz Xtruded Products, LP

The Schulz Group of Companies has more than 65 years experience in manufacturing a complete size range of high-performance pipes and fittings. With our unique cold forming technique we produce the full scope of alloy, stainless and high alloy piping products available for the chemical and petro-chemical, power and nuclear power plant industries and water treatment plants.

Schulz Xtruded Products (SXP) in Tunica, Mississippi, USA is the most recent addition to the Schulz Group of Companies.

The Tunica plant is dedicated to produce both hot and cold finished seamless stain-less, high alloy, nickel base and titanium pipe starting from 8” NPS up to 24” O.D. with a maximum length of 16m.

In addition, SXP is specialized in the pro-duction of metallurgical bonded clad pipe(SX-Clad) particularly for the oil and gas industry.

The full scope clad combinations is shown on page 16.

YOUR TASK FORCE IN CLADDING

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SX-CLAD


SX-Clad - Metallurgical Bonded Seamless Clad Pipe

A variety of techniques have been used to produce bi-metallic pipe products to handle the more corrosive product streams en-countered by today‘s oil and gas industry.These products consist of a thin corrosion-resistant ID (CRA) pipe inside a heavier,stronger OD (host) pipe for pressure contain-ment. The techniques employed to produce these products include welding roll-bonded clad plate, weld overlay of both welded and seamless pipe, and merely mechanic-ally lining a host pipe with a thin, welded CRA pipe.

Based on its many years of experience using its cold forming technology, the Schulz Group of Companies, in a joint research program with Petrobras Brazil, has develop-ed an improved process, SX-Clad, for produc-ing a metallurgical bonded seamless clad pipe which is not harmed by the deficiencies associated with other processes.

The Schulz process uses its ultra high pressure technology to prepare billets that, when hot extruded, form a very thin but

extremely strong diffusion bond between the CRA and host pipe. In addition SX-Clad offers excellent weldability, heat transfer and thermal stability.

Pipelines and process piping are being exposed to increasingly severe corrosive environments as new reserves discovered are in deepwater locations. This extreme depth results in higher temperatures and pressures which add to the aggressiveness of the corrosion encountered. Methods to combat this situation include the introducti-on of inhibitor systems and the use of more costly piping materials such as duplex, super duplex and nickel base alloys.

The oil and gas industry has used bi-metallic or clad piping in which a relatively thin layer of an expensive corrosion resistant alloy (CRA), such as Incoloy, is placed in the ID of a less expensive host pipe, suchas X-65. Highly improved corrosion resistance compared to solid alloy pipe at reduced cost compared to solid CRA pipe is the major advantage to this approach.


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APPLICATION


SX-Clad pipe and fittings are composite products combining the best properties ofdifferent metals.

Advantages:

• Highmechanicalstrength

• ProvencorrosionresistanceoftheNiCr family of alloys

• Reductionofthewallthicknessandweight compared to solid CRA pipes due to the higher strength of the carbon steel host pipe

• Superiormechanicalpropertiesduetoboth components being wrought structures rather than one wrought and the other as-cast

• Mechanicalpropertiesalsoenhanced due to 100% bonding

• Thethin,100%bondwithSX-Clad provides the maximum heat transfer of any clad system available

• Acompleterangeofcold-formedfittings can be produced from all SX-Clad combinations 1:1 produced from standard sized SX-Clad pipe. No special dimensions and tolerances are needed as starting material for the fitting production

• TheabilityoftheSX-Clad process to control CRA and host dimensions provides for ease of fit up and field welding

As a result the SX-Clad pipe and fittings provide superior mechanical properties, areeconomically more efficient and as corrosion resistant as a solid CorrosionResistant Alloy (CRA) pipe and fittings.


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MANUFACTURING PROCESS


SX-Clad Process

1. Billet Assembly

The CRA billet is placed inside the host pipe. After closing the ends the billet will beexpanded hydraulically to form an extreme-ly tight fit. The diagram on the right showsthis process.

2. Billet Heating

The assembled and expanded composite billet is then heated to the extrusion tempe-rature under controlled conditions to avoid separation of the two components. This controlled practice prevents oxidation of the interface that would interfere with the diffusion bonding mechanism.

3. Extrusion

The hot composite billet is then extruded to the final pipe dimensions. Diffusion bonding reached by the high temperature and shear stresses occurring during extrusion. The extrusion process is pictured on the right.


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SX-CLAD


Strength of Bonding

During extrusion the extremely thin oxide films formed at ambient temperatures on the host ID and CRA OD prior to billet assembly are ruptured due to the elongati-on associated with the extrusion operation. Since no air is present during the heat up, the nascent surfaces at the rupture sites are sufficiently active to permit diffusion across the interface at the temperatures and pressures present during extrusion.

The strength and ductility of the bond formed using this process are equivalent to that of the individual component alloys.

The SEM‘s and EDAX scans shown on the next pages, both demonstrate this phenomena.The EDAX scans indicate that chromium migration from the CRA into the carbon host pipe is the principal mobile element.

Right:Cut of a LR180° SX-Clad Elbow P9/904L


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MICROGRAPH & EDAX ANALYSES


SEM of SX-Clad pipe X65/ Alloy 625

Top left:As-hardened X65/625 SX-Clad flattening sample showing extremely strong bond between components that blunts fracture from both destroying bond and progress-ing into CRA layer.

Middle left:SX-Clad pipe after tempering showing 100% perfect bond after flattening.

Bottom left:EDAX scan across bond area of SX-Clad X-65/NO6625 showing diffusion of Cr and Ni across interface during extrusion as being the principal bonding mechanism.


Top right:ASTM A262 Practice E:Result of ASTM A262 Practice E corrosion test of X65/625 SX-Clad sensitized at 1250 F showing no fissures or intergranular corrosion.

Bottom right:Thermal cycling:5 cycles soak at 700°C (1300°F) hold for 30 minutes, air cool to room temperature100X magnification passing specimens, no intergranular fissures or cracks detected.

Tensile test results of base material area after austenizing at 1950°F, quenching and temper-ing at 1100°F for one how per ASTM A370, E8

All SEM and EDAX work provided courtesy of Mississippi State University

Orientation Diameter UTS ksi YS at 2% Elongation % Reduction offset ksi 1” Gauge of area %

longitudinal 0.244” 107.2 94.6 21.1 71.2

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MICROGRAPH & EDAX ANALYSES


SEM of SX-Clad pipe SS347/ SS317L

Top left:EDAX analysis of host pipe (347) showing it stabilized with Nb and containing no Mo.

Middle left:EDAX analysis at interface showing diffusion of Nb from the host and Mo from the CRA into this area.

Bottom left:EDAX analysis of CRA layer (317L) showing approximately 3% Mo.


SEM of SX-Clad pipe P9/ 904L

Top right:Graph of the chemical analysis of the host pipe in P9

Middle right:Graph of the chemical analysis in the diffu-sion zone showing Cr and Ni being the main bonding elements during extrusion

Bottom right:Graph of the chemical analysis of the CRA layer in 904L

Cladding Alloys

SS304/304LSS316/316LSS317/317LSS321/321HSS347/347HSS904/904LAlloy 825Alloy 625

Product Program

Seamless SX-Clad Pipe• 6”NBupto14”O.D.asoftoday SCH 80S up to SCH 160 6-16m lengths Clad Thickness 2.5 to 4mm

Full range of BW fittings 1:1 produced from SX-Clad pipe• Elbows• Concentric&EccentricReducers• EqualTees&ReducedTees• Caps

SX-Clad pipe and fittings can be produced in small quantities to satisfy customers needs.

Available Combinations

Base Material

Carbon Steel Hi Yield Grades Low Alloy Steels Stainless Steels Chrome MolySteels

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PRODUCTION PROGRAM



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TESTING


Finishing & Inspection

After extrusion the SX-Clad pipe is finishedand inspected according to highest demands:

•VisualinspectionofODandIDsurface condition/Verifyingtargetedhotdimensions

•Heattreatment(ifrequired)

• Mechanicalandphysicaltesting

• Rotarystraightening

•ODandIDblasting

•BoroscopeID

•100%UTforbondintegrity,totalwall and EM for CRA thickness

The bond integrity, CRA thickness, total wall thickness and volumetric quality are allmeasured simultaneously with equipment recently developed by SXP and NDT Technologies.

Figure I:All combinations have also passed “H” value flattening tests.

Figure II:Demonstration of the excellent ductility of the bond.

Figure III:The fracture in the X65 to be totally blunted at the Alloy 625 interface shows the very high strength of the bond.


Figure I Figure II Figure III

Schulz Group of Companies · Headquarter · Kuhleshütte 111 · 47809 Krefeld · GermanyPhone +49-2151-517-0 · Fax +49-2151-517-101 · [email protected] · www.wschulz.com

Documents

SEAMLESS METALLURGICAL BONDED CLAD PIPE & · PDF fileCOMPANY PHILOSOPHY 4 SX-CLAD SCHULZ GROUP OF COMPANIES SX-Clad - Metallurgical Bonded Seamless Clad Pipe A variety of techniques