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Subject: search.filters.subject.316L stainless steel

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    Laser surface polishing of material extrusion additively manufactured 316L stainless steel
    (2026-02-01)
    Hemwat, Jirayu
    ;
    Saetang, Viboon
    ;
    Qi, Huan
    ;
    Seenawat, Mongkol
    ;
    Chankitmunkong, Suwaree
    Material extrusion additive manufacturing (MEX) provides a cost-effective pathway for fabricating metallic components; however, its industrial use remains limited by surface defects and high roughness. This study evaluates nanosecond laser polishing (LP) as a post-processing method to improve the surface characteristics of 316L stainless steel produced by Bound Metal Deposition (BMD). The objective is to understand how laser beam diameter, scan speed, and processing atmosphere (air vs. argon) influence surface integrity. Polishing experiments were performed using 50 W and 100 W laser power with beam diameters of 200 and 400 μm at scanning speeds of 100–400 mm/s. Areal roughness (S<inf>a</inf>), surface waviness (W<inf>a</inf>), surface chemistry, subsurface microstructure, and electrochemical response were systematically characterized. Laser polishing reduced S<inf>a</inf> from 2.003 μm to 0.371 μm (81 % reduction) and W<inf>a</inf> by up to 43 %. Polishing in argon produced cleaner melt tracks with minimal oxidation, a refined remelted layer, and enhanced passive film formation, leading to improved corrosion resistance (E<inf>corr</inf> improved from −0.466 V to −0.062 V). These findings demonstrate that LP effectively mitigates the surface limitations of BMD-fabricated stainless steel and provide process guidelines for achieving high-quality functional surfaces in MEX metal components.
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    Dry-sliding wear of the 316L/h-BN composites produced under crack ammonia atmosphere
    (2020-01-01)
    Chusong, Ekkarat
    ;
    Kansuwan, Panya
    ;
    Ohtake, Naoto
    ;
    Wila, Pongsak
    ;
    Tosangthum, Nattaya
    Wear is one of different problems in mechanical failures of moving components. When a component encounters friction force on its surface, crack initiation tends to occur and wear follows crack propagation. Thus, the moving parts of automobiles should have proper wear resistance for long-time services, in addition to having high strength and hardness for heavy load operation. A self-lubricating material with compromised tribological and mechanical properties is important for some moving components. In this work, self-lubricating composites, metal matrix composites embedded with a solid lubricant, made from 316L stainless steel powder mixed with different hexagonal boron nitride (h-BN) contents of 10%, 15% and 20% by volume. The mixed powders were compacted into green parts (according with MPIF Standard 42) with density of 6.5 g·cm<sup>-3</sup>. Then, the green parts were sintered at 1100, 1150, 1200, 1250 and 1300°C under cracked ammonia (75% H<inf>2</inf>+25% N<inf>2</inf>) atmosphere for 60 min. The experimental results revealed that increases of hardness and strength sintered 316L matrix by reduction of pore amount and size were due to the increase of sintering temperature. However, the increase of h-BN content resulted in increase of pore amount and size. Additions of h-BN content up to 20 vol. % reduced friction coefficient of the sintered composites. At sintering temperatures of equal to and higher than 1200°C, h-BN did not react with 316L stainless steel powders to form intergranular boride phase. The sintered composites produced under the maximum experimental sintering temperature of 1300°C showed low specific wear rate.