Leak-tight crack repair for 304L stainless steel using friction surfacing

Journal Article · Fri May 13 00:00:00 EDT 2022 · Journal of Manufacturing Processes

DOI:https://doi.org/10.1016/j.jmapro.2022.05.004· OSTI ID:1906972

Agiwal, Hemant ^[1]; Yeom, Hwasung ^[1]; Ross, Kenneth A.  ^[2]; Sridharan, Kumar ^[1]; Pfefferkorn, Frank E. ^[1]

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1. Univ. of Wisconsin, Madison, WI (United States)
2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Here, friction surfacing (FS) was investigated as a method for sealing 50 μm wide thru-cracks in 3-mm-thick 304L stainless steel (304L) plate. Friction surfacing was performed using two sizes of 304L consumable rod, with diameters of 9.52 mm and 12.7 mm, on two substrate conditions (clean and oxidized). Friction surfacing was able to deposit a 600 μm thick coating and repair cracks to a depth of 100 μm - 200 μm below the original surface, when using the 12.7-mm-diameter consumable rod for both substrate conditions. Helium leak rates of 10^-10 atm-cc/s were achieved on crack repairs, designating them as leak-tight by the ANSI N14.5 standard. Optical and scanning electron microscopy were used to investigate the coating microstructure and bond interfaces. In this study, the 12.7-mm-diameter rod performed better with disruption of the oxide layer on the oxidized substrate and providing a more homogenous coating. Mechanical properties of the coated samples were evaluated by performing micro-indentation, tensile, bending, and adhesion testing. Higher hardness in the coatings was observed due to the fine equiaxed grains resulting from dynamic recrystallization. Complete consolidation of plastically deformed material on the substrate and a strong diffusion bond across the interface was observed. This was reflected in tensile and bending properties of the FS coatings being comparable to those of uncoated specimen. No delamination of the FS coating was observed during adhesion testing. The results demonstrate that friction surfacing is a viable option to seal cracks in stainless steels.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-76RL01830; NE0008801
• OSTI ID: 1906972
• Report Number(s): PNNL-SA-168919
• Journal Information: Journal of Manufacturing Processes, Vol. 79; ISSN 1526-6125
• Publisher: Society of Manufacturing Engineers; Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Friction surfacing
Mechanical properties
Stainless steel
Crack repair
Helium leak test