Reconditioning Power-Generation Components with Thermal Spray
The growth of power-generation facilities throughout the world has been unprecedented. With this expansion, plant superintendents and maintenance supervisors will tell you that a tremendous amount of effort is expended behind the scenes to keep these power generating facilities running smoothly. These facilities face numerous corrosion and/or wear issues, and maintenance must regularly be performed on various machines and systems. In an effort to reduce
downtime, plant superintendents and maintenance supervisors have turned to and have come to depend upon thermal spray technology to extend the life of power-generating components and systems. Coatings manufactured by this technology are being used throughout the power-generating industry in applications
such as water pumps, conveyor screws, boiler tubes, and coal crushers.
Masking for Thermal Spray Coatings
When specific areas of a part must be thermally sprayed, the areas that are not to be coated must be masked. The masking method and materials used need to be selected based on the spray equipment and automation employed to apply the coating. The choice of maskant for each job is essential to the ultimate integrity of the coating and the total cost to process the part(s).
Assessing Toughness Levels for Steels to Determine the Need for PWHT
Postweld heat treatment (PWHT) is applied to welded steel assemblies primarily to reduce the likelihood of brittle fracture. This is achieved through a reduction in the level of tensile residual stresses and through tempering of hard, potentially brittle, microstructural regions. There are, of course, economic and logistical incentives to avoid PWHT wherever possible.
D. J. Abson et al.
Grit Blasting: Starting Your Thermal Spray Job Correctly
Grit blasting, or the roughening of the substrate to be thermal sprayed, is as important as the spraying itself. It cleans the surface and roughens the substrate to form an anchor tooth pattern to improve the coating adhesion. The measurement and control of the surface roughness pattern need to be better monitored and controlled for thermal spray coatings. This article is based on my experience working for a manufacturer of grit blast equipment. It looks at what is common practice, current writings, and recommended procedures to improve this practice.
E. R. Sampson
WELDING RESEARCH SUPPLEMENT
Prediction of Ferrite Number of Duplex Stainless Steel Clad Metals Using RSM (.pdf)
Response surface methodology (RSM) was used to establish a relationship between process parameters and Ferrite Number for duplex stainless steel clad metals.
T. Kannan and n. Murugan et al.
Sheet Using a High-Power Diode Laser (.pdf)
Microstructures when Welding Automotive Advanced High-Strength Steels
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WELDING JOURNAL - May 2006, Volume 85, Number 5