scholarly journals EVALUATION OF Ni-Cr-Mo ALLOY APPLIED BY WELD OVERLAY CLADDING ON CARBON STEEL FOR USE IN NaCl 3.5% MASS SOLUTION

2021 ◽  
Vol 3 (3) ◽  
pp. 355-364
Author(s):  
Fabio P. D. de Araujo ◽  
Fernando B. Mainier ◽  
Brígida B. de Almeida
Keyword(s):  
Carbon Steel ◽  
Weld Overlay

Integrity of Weld Overlay of Flexible Joints and Lined Pipe

2015 ◽  
Author(s):  
Petrônio Zumpano ◽  
Alexandre G. Garmbis ◽  
Eduardo V. Oazen ◽  
Luis Guilherme T. S. Leite ◽  
Rafael N. Silva
Keyword(s):  
Carbon Steel ◽  
Ultrasonic Inspection ◽  
Base Material ◽  
Probability Of Detection ◽  
Internal Layers ◽  
Flexible Joints ◽  
Weld Overlay ◽  
Corrosion Resistant ◽  
Alloy 625 ◽  
Sulfide Stress

This paper describes different alternatives to be adopted to assess the integrity of weld overlays of flexible joints and lined pipes in offshore pipeline and riser projects. Protective layers are adopted as an interesting alternative to full thickness corrosion resistant alloys due to the possibility to adopt carbon steel as base material in order to reduce overall material costs. UNS N06625 (alloy 625) is generally selected for internal layers, such as weld overlay steels, lined pipes or clad pipes because of its sulfide stress cracking (SSC) resistance and outstanding weldability. However, unless the long-term integrity of the cladding or overlay as a protective layer can be demonstrated under the intended service conditions, the base material shall also be resistant against sulfide stress corrosion cracking. Due to low resistance of carbon steel to corrosion fatigue in the presence of contaminants in fluid content, the rupture of thickness of CRA (Corrosion Resistant Alloy) layer becomes a failure mode. An Engineering Critical Assessment (ECA) shall be performed in order to assess if circumferential planar flaws in weld overlay regions will not propagate through the CRA layer, thus exposing the base material, when submitted to critical cyclic loads during the service life. Such analysis would involve fatigue crack growth simulation and surface interaction of full circumferential embedded defects to determine the maximum weld overlay pass height to be limited by machining. This limited height of machined layers should guarantee that a full circumferential flaw will withstand the operational fatigue life. However, this is a very time consuming manufacturing process and would implicate additional concerns for long extensions due to out of straightness and out of roundness. Alternatively, the ECA results may be used to determine the flaw acceptance criteria and required probability of detection of volumetric non-destructive testing. Recent developments in ultrasonic inspection were successfully adopted and represent a better solution for alloy 625 weld overlay in terms of project scheduling and manufacturing costs. Radiographic testing may also be used provided it meets the required sensitivity, in terms of image quality indicators (IQI). Anyway, validation tests shall be performed to demonstrate adequate reliability to detect the minimum required flaw height.

Challenges About Testing, Welding and NDT of CRA Pipelines in Brazilian Pre-Salt

2012 ◽  
Author(s):  
Petrônio Zumpano ◽  
Genaro Zanon ◽  
Alexandre Galiani Garmbis ◽  
Luciano Braga Alkmin ◽  
Manfred Ronald Richter ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Material Selection ◽  
Design Strength ◽  
Weld Overlay ◽  
Campos Basin ◽  
Variable Level ◽  
Pipeline Welding ◽  
Girth Welds ◽  
Pipeline Design ◽  
Number Of Passes

Some new pre-salt fields at Santos Basin in Brazil are located in water depths as deep as 2200m and about 300 km away from the coast. There is variable level of contaminants in the produced fluid, mainly CO2 that affects the material selection of the infield flowlines and risers. Based on these constraints, Petrobras has selected UNS N06625 clad or lined steel linepipes to develop the first fields in Pre-Salt area and also the module 3 of Roncador a post-salt field in Campos Basin. Several challenges have arisen during design, construction and installation of these facilities related to pipeline welding procedures, NDT inspection and Engineering Critical Assessment (ECA). Firstly weld overmatching condition may not be fully achieved due to differences in mechanical properties between UNS 06625 and API X65, and concern increases when reel-lay installation method is chosen. Another welding issue is the maximum interpass temperature of nickel alloys (DNV and PETROBRAS standards limit that to 100°C) and this impacts pipeline installation productivity. Thirdly, back purging characteristics and number of passes protected with purging gases affects the possibility of root oxidation. Also, the inspection of the weld overlay in the pipe end of lined linepipes is other point of great concern. As defect sizing is mandatory for ECA, lined pipes have been designed with a weld overlay length which allows the inspection of the final girth weld by AUT. However, AUT solutions are normally more efficient in rolled or extruded materials than in weld overlaid ones. Additionally, the ECA methodology for both girth welds and weld overlay has complexities that are not usually addressed in a regular ECA for carbon steel pipelines (e.g. internal misalignment of girth welds in risers has stringent requirements because of its effects on fatigue performance and, consequently, the ECA girth weld criteria). Also CRA clad/lined pipelines and risers qualification program may include additional testing when compared with usual carbon steel welding qualification process (namely pitting and intergranular corrosion, full scale fatigue, spooling trials of lined linepipes, segment testing for ECA, and others). Finally, the contribution of clad/lined layer in pipeline design strength is also discussed. This work presents challenges PETROBRAS has faced at design and construction phases of on-going Guaré and Lula-NE pre-salt fields and Roncador field projects, as well as the solutions proposed by the project team in order to overcome the issues raised during project execution.

Application of Unifuse Overlay Tubes in the Convection Section of Waste-to-Energy Boilers

2003 ◽  
Author(s):  
Pedro Amador ◽  
George Lai
Keyword(s):  
Carbon Steel ◽  
Corrosion Protection ◽  
Steel Substrate ◽  
Gas Metal Arc Welding ◽  
Steel Tube ◽  
Waste To Energy ◽  
Stainless Steel Tube ◽  
Weld Overlay ◽  
Alloy 625 ◽  
Gtaw Process

The modern weld overlay applied by automatic gas-metal-arc welding (GMAW) process using Ni-Cr-Mo-Nb alloy 625 has been extremely successful in providing corrosion and erosion/corrosion protection for the waterwalls of waste-to-energy (WTE) boilers for over a decade. Without alloy 625 weld overlay protection, the carbon steel waterwall of a waste-to-energy boiler would be corroded through in a matter of months. The overlaid waterwalls for numerous WTE boilers have shown excellent performance results with services up to 10 years or more. Welding Services Inc. has developed a patented process for manufacturing weld overlay bimetallic tubes involving GMAW/GTAW process. Unifuse® 625 overlay tubing with carbon steel substrate has been successfully used as screen tubes, superheater tubes and generating banks in the convection section. The overlay tubes have successfully replaced such corrosion protection methods as stainless steel tube shields and refractories.

Experience With Weld Overlay and Solid Alloy Tubing Materials in Waste to Energy Plants

2004 ◽  
Author(s):  
Larry Paul ◽  
Michael Eckhardt ◽  
Andreas Ossenberg-Engels ◽  
Gregg Clark ◽  
Bern Hoberg
Keyword(s):  
Carbon Steel ◽  
Corrosion Protection ◽  
Nickel Alloys ◽  
Waste To Energy ◽  
Solid Alloy ◽  
Weld Overlay ◽  
Boiler Tubes ◽  
Materials Used ◽  
Tube Life ◽  
Energy Plants

Corrosive conditions in waste to energy boilers produce rapid wastage rates of traditional boiler tube materials. It is not unusual to see corrosion rates in the range of 1 to 3 mm/y (40–120 mpy) on carbon steel boiler tubes and occasionally corrosion occurs at even higher rates. In the mid1980’s there were several boilers that experienced corrosion failures of carbon steel waterwall tubes in less than 6 months of service (1,2). Because of this experience, it has become accepted that some type of corrosion protection is required for boiler tubes in refuse-to-energy boilers. Over the years, many different alloys have been evaluated to improve tube life in waste-to-energy boilers. The most successful materials used for corrosion protection are nickel alloys.

scholarly journals Weld Overlay Technique using Different Filler Rod Size to Overcome Internal Corrosion of Low Carbon Steel Base Metal

2020 ◽  
Vol 9 (3) ◽  
pp. 654-660
Keyword(s):  
Carbon Steel ◽  
Base Metal ◽  
Low Carbon Steel ◽  
Chloride Ions ◽  
Low Carbon ◽  
Internal Corrosion ◽  
Weld Overlay ◽  
Electrode Size ◽  
Steel Base ◽  
Overlay Welding

Overlay welding is commonly used to repair and replace the affected corroded surface of the base metal of a component. In other words, it is used to restore the original dimensions of the component. Weld overlay usually applies a corrosion resistant or hard facing layer onto the base metal. This experiment is to determine the suitable filler rod size in repairing corroded low carbon steel (LCS) base metal, respectively to the affected area and to identify the type of distortion occurring on the weldment. It is also to examine the microstructure of the joint between the overlay weld and corroded low carbon steel base metal using SEM/EDX. The overlay welding process was conducted on the corroded samples using SMAW process at defined attacked corroded areas. Filler electrode E-7018 with two diameter sizes of 3.2mm and 2.6mm were selected. It was found that the bigger electrode size produced higher degree of distortion angle compared to smaller electrode size. Resulting from the metallographic and SEM/EDX analysis, the joint between weld overlay and corroded LCS were fused well without any sign of oxides or other impurities present. Overlay welding also remove the sign of chloride ions that cause the LCS base metal to corrode. Thus, the repairing technique using overlay welding was found successful in repairing corroded LCS base metal. Therefore, the most suitable electrode size to do overlay welding on corroded low carbon steel base metal is 2.6 mm diameter electrode

Duplex and ferritic stainless steel sheet linings versus weld overlay and other metallic corrosion-resistant barriers

TAPPI Journal ◽  
2015 ◽  
Vol 14 (7) ◽  
pp. 491-495
Author(s):  
DAVID C. BENNETT
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Weld Overlay ◽  
Alkaline Pulping ◽  
Thermal Expansion Coefficients ◽  
Industry Standards ◽  
Steel Grades ◽  
Sprayed Coating ◽  
Metallic Corrosion ◽  
Steel Substrates

Sheet linings made from stainless steel can protect carbon steel substrates at lower initial direct cost for installation and subsequent direct inspection than weld overlay and thermal sprayed coating. Closely matched thermal expansion coefficients of ferritic and duplex stainless steel grades with carbon steel allow large “tile pieces” in reliable, leak-proof linings compared to linings from austenitic grades, simplifying and speeding installation. Sheet linings with ferritic and duplex grades typically have lower unit costs than weld overlay and thermal sprayed coatings. Ferritic and lean duplex grades resist corrosion and stress corrosion cracking in most alkaline pulping and liquor recovery environments. Super-duplex grades can replace acid-resistant brick linings in D-stage bleaching equipment, including pre-retention tubes and towers. Carefully specified sheet linings of ferritic and duplex stainless steels, professionally installed in accordance with longstanding industry standards, are reliable and economical protective barriers, especially compared with weld overlay, in many applications in modern pulp

Pyrolytic carbon filaments and associated catalytic particles formed in steel tubes

1984 ◽  
Vol 42 ◽  
pp. 662-663
Author(s):  
Y. L. Chen ◽  
J. R. Bradley
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Catalyst Particle ◽  
Pyrolytic Carbon ◽  
Plain Carbon Steel ◽  
304 Stainless Steel ◽  
Hydrocarbon Gases ◽  
Steel Tubes ◽  
Filamentous Carbon ◽  
Carbon Filaments

Considerable effort has been directed toward an improved understanding of the production of the strong and stiff ∼ 1-20 μm diameter pyrolytic carbon fibers of the type reported by Koyama and, more recently, by Tibbetts. These macroscopic fibers are produced when pyrolytic carbon filaments (∼ 0.1 μm or less in diameter) are thickened by deposition of carbon during thermal decomposition of hydrocarbon gases. Each such precursor filament normally lengthens in association with an attached catalyst particle. The subject of filamentous carbon formation and much of the work on characterization of the catalyst particles have been reviewed thoroughly by Baker and Harris. However, identification of the catalyst particles remains a problem of continuing interest. The purpose of this work was to characterize the microstructure of the pyrolytic carbon filaments and the catalyst particles formed inside stainless steel and plain carbon steel tubes. For the present study, natural gas (∼; 97 % methane) was passed through type 304 stainless steel and SAE 1020 plain carbon steel tubes at 1240°K.

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