Changes in surface characteristics of stainless steel polished by nanosecond laser based on beam coupling

2021 ◽  
Author(s):  
Xiaoxiao Chen ◽  
Yuan Li ◽  
Huihui Zhang ◽  
Wenwu Zhang
Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1376
Author(s):  
Alex Quok An Teo ◽  
Lina Yan ◽  
Akshay Chaudhari ◽  
Gavin Kane O’Neill

Additive manufacturing of stainless steel is becoming increasingly accessible, allowing for the customisation of structure and surface characteristics; there is little guidance for the post-processing of these metals. We carried out this study to ascertain the effects of various combinations of post-processing methods on the surface of an additively manufactured stainless steel 316L lattice. We also characterized the nature of residual surface particles found after these processes via energy-dispersive X-ray spectroscopy. Finally, we measured the surface roughness of the post-processing lattices via digital microscopy. The native lattices had a predictably high surface roughness from partially molten particles. Sandblasting effectively removed this but damaged the surface, introducing a peel-off layer, as well as leaving surface residue from the glass beads used. The addition of either abrasive polishing or electropolishing removed the peel-off layer but introduced other surface deficiencies making it more susceptible to corrosion. Finally, when electropolishing was performed after the above processes, there was a significant reduction in residual surface particles. The constitution of the particulate debris as well as the lattice surface roughness following each post-processing method varied, with potential implications for clinical use. The work provides a good base for future development of post-processing methods for additively manufactured stainless steel.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2240 ◽  
Author(s):  
Peter Gregorčič ◽  
Marjetka Conradi ◽  
Luka Hribar ◽  
Matej Hočevar

Controlling the surface wettability represents an important challenge in the field of surface functionalization. Here, the wettability of a stainless-steel surface is modified by 30-ns pulses of a Nd:YAG marking laser (λ = 1064 nm) with peak fluences within the range 3.3–25.1 J cm−2. The short- (40 days), intermediate- (100 days) and long-term (1 year) superhydrophilic-to-(super)hydrophobic transition of the laser-textured surfaces exposed to the atmospheric air is examined by evaluating its wettability in the context of the following parameters: (i) pulse fluence; (ii) scan line separation; (iii) focal position and (iv) wetting period due to contact angle measurements. The results show that using solely a short-term evaluation can lead to wrong conclusions and that the faster development of the hydrophobicity immediately after laser texturing usually leads to lower final contact angle and vice versa, the slower this transition is, the more superhydrophobic the surface is expected to become (possibly even with self-cleaning ability). Depending on laser fluence, the laser-textured surfaces can develop stable or unstable hydrophobicity. Stable hydrophobicity is achieved, if the threshold fluence of 12 J cm−2 is exceeded. We show that by nanosecond-laser texturing a lotus-leaf-like surface with a contact angle above 150° and roll-off angle below 5° can be achieved.


Author(s):  
Moo-Keun Song ◽  
Jong-Do Kim ◽  
Dong-Sig Shin ◽  
Su-Jin Lee ◽  
Dae-Won Cho

In this study, the parameters for underwater laser cutting of 50-mm thick stainless steel, which is typically used in nuclear power structures, are investigated. The focal position of laser beam significantly affects the cutting quality. In particular, in the cutting of the thick sample, change in the focal position determines the kerf width and the roughness of the cut surface. Moreover, the effects of the variation of kerf width and the cut surface characteristics on the focal position of the laser beam are investigated. As the focal position moved to the inside of the material, the upper kerf width increased, but the quality of the cut surface was improved.


Applied laser ◽  
2013 ◽  
Vol 33 (6) ◽  
pp. 586-590 ◽  
Author(s):  
黄天琪 Huang Tianqi ◽  
李建美 Li Jianmei ◽  
路长厚 Lu Changhou ◽  
王爱群 Wang Aiqun ◽  
张金琪 Zhang Jinqi

2020 ◽  
Vol 31 (17) ◽  
pp. 175301
Author(s):  
Md Abu Taher ◽  
Sajin Ponnan ◽  
Hiteswar Prasad ◽  
Desai Narayana Rao ◽  
Sri Ram G Naraharisetty

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1119 ◽  
Author(s):  
Kun V. Tian ◽  
Francesca Passaretti ◽  
Adelaide Nespoli ◽  
Ernesto Placidi ◽  
Roberta Condò ◽  
...  

Neutron scattering in combination with scanning electron and atomic force microscopy were employed to quantitatively resolve elemental composition, nano- through meso- to metallurgical structures and surface characteristics of two commercial stainless steel orthodontic archwires—G&H and Azdent. The obtained bulk composition confirmed that both samples are made of metastable austenitic stainless steel type AISI 304. The neutron technique’s higher detection sensitivity to alloying elements facilitated the quantitative determination of the composition factor (CF), and the pitting resistance equivalent number (PREN) for predicting austenite stability and pitting-corrosion resistance, respectively. Simultaneous neutron diffraction analyses revealed that both samples contained additional martensite phase due to strain-induced martensite transformation. The unexpectedly high martensite content (46.20 vol%) in G&H was caused by combination of lower austenite stability (CF = 17.37, p = .03), excessive cold working and inadequate thermal treatment during material processing. Together, those results assist in revealing alloying recipes and processing history, and relating these with corrosion resistance and mechanical properties. The present methodology has allowed access to unprecedented length-scale (μm to sub-nm) resolution, accessing nano- through meso-scopic properties. It is envisaged that such an approach can be extended to the study and design of other metallic (bio)materials used in medical sciences, dentistry and beyond.


2004 ◽  
Vol 65 (7) ◽  
pp. 972-976 ◽  
Author(s):  
Christopher B. O'Sullivan ◽  
Alicia L. Bertone ◽  
Alan S. Litsky ◽  
James T. Robertson

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