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1

Enhanced wear and corrosion performance of stainless steel 316L with addition of different weight percentages of GNP

Veeramallu Kalyanamanohar, Krishna Alluru Gopala

Composites Theory and Practice

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2024

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R. 24, nr 1

25--32

EN

The present study reports on the significant improvement in the wear and corrosion resistance of SS316L by adding Graphene nanoplatelets (GNP) of varying wt.% (0.25, 0.5, and 0.75), composites which were prepared by the pressureless sintering technique. The GNP addition can significantly improve the wear and corrosion resistance of SS316L. The wear and corrosion rates for the 0.5 wt.% GNP composite were reduced by 43% and 98%, respectively. The corrosion morphology showed that pitting corrosion was reduced by reinforcing 316L with 0.5 wt.% GNP. Moreover, the intergranular sites were more vulnerable to the corrosion medium when GNP was used at 0.75 wt.%. The worn surface morphology revealed that the tribofilm reduces the coefficient of friction and wear rate due to the lubricating nature of GNP. The presence of GNP was confirmed by Raman spectroscopy in terms of the tribofilm.

2

Influence of L-PBF additive manufacturing parameters on the residual stresses and thermal distortions in AISI 316L stainless steel parts

Santos O., Batalha G.F., Farias V., Seriacop V., Bordinassi E.C., Adamiak M.

Archives of Materials Science and Engineering

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2024

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Vol. 127, nr 1

12--22

EN

Purpose: The work aimed to numerically model through the Finite Element Method (FEM) the distribution of residual stresses and thermal distortions in parts generated by Laser Powder Bed Fusion (L-PBF) in stainless steel AISI 316L and validate the results obtained through experimental measurements on previously manufactured parts. Design/methodology/approach: The design methodology followed a numerical approach through the Finite Element Method (FEM), the distribution of residual stresses and thermal distortions in parts generated by Selective Laser Powder Bed Fusion (L-PBF) in stainless steel AISI 316L and the FEM approach was validated trough the results obtained through experimental measurements on previously manufactured parts. The influence on three levels was verified through complete factorial planning of some manufacturing parameters, such as laser power, speed, and distance between scans (hatch), on the stress and distortion results of the samples and also on the samples simulated by FEM. Findings: When results were compared about the average diameters, a relative error of less than 2.5% was observed. The average diameter was influenced by power and speed. Increasing power decreased the average diameter of the samples, while increasing speed and hatch increased the average diameter. When results are compared to measure the residual stresses, it is observed that the relative error was less than 1%. Power, speed, and the hatch itself influenced the residual stress. Increasing power increases residual stress while increasing speed and hatch decreases residual stress. The cooling rate and the transient thermal history are the control factors that influence the residual stresses and are directly related to the process parameters. The computational modelling followed by measurements and calibrations carried out in the experimental stages proved to be efficient and enabled the reproduction of thermal distortion and residual stresses with statistical confidence. prediction of thermal distortions and residual stresses using the machine learning approach. Future research will study heating the building platform, which should also impact residual stresses. Practical implications: Based on the results obtained in this research, it will be possible to select better additive manufacturing parameters for manufacturing 316L stainless steel parts. The parameters evaluated in the work were laser power, scanning speed, and hatch. Originality/value: The innovation of the work lies in the robust simulation of the thermo-elastic behaviour of samples subjected to the additive manufacturing process, where it was possible to accurately relate the thermal distortions and residual stresses that appeared in the samples printed with the parts modelled by the FEM. The numerical-experimental validation makes it possible to extrapolate the studies to several other manufacturing parameters using only computational simulation and work with a more significant amount of data for a prediction study.

3

Impact of build location on dimensional accuracy of 316L parts using SLM

Daoud M.A., Hayani Mechkouri M., Chairi Y., Haouari K.B., Reklaoui K.

Archives of Materials Science and Engineering

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2024

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Vol. 125, nr 2

75--85

EN

Purpose: The objective of this study is to comprehensively investigate the printability characteristics of a selective laser melting (SLM) system, which will be achieved through the development of a benchmark test part. In addition, the effect of the build location on the dimensional accuracy and precision of 316 L stainless steel parts produced by SLM was thoroughly evaluated. Design/methodology/approach: The benchmark part was designed using Catia CAD software. Parts were printed using a professional SLM 3D printer and 316L stainless steel powder as a material. Findings: The results showed that to achieve exceptional dimensional accuracy in SLM parts, it is important to select the build location carefully. They also highlighted the critical role of gas distribution control in improving the precision of layer-by-layer deposition. The thorough evaluation of dimensional deviations at different build locations showed that optimal results were consistently achieved at position F within the build cham-ber. Research limitations/implications: Further studies could investigate other factors affecting dimensional variations and surface roughness and enhance the comprehension of the interactions between the process parameters and the building position on the build platform. Originality/value: The paper outlines the creation and production of a benchmark model used to assess the maximum capacity of SLM systems in manufacturing parts with ultimate dimensional precision. The effects of build location on dimensional accuracy are also explored in the given study.

4

Surface Characteristics and Wear Resistance of 316L Stainless Steel after Different Shot Peening Parameters

Walczak Mariusz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 3

124--132

EN

The study was conducted to evaluate the effect of ZrO2-based ceramic beads shot peening on the performance properties of AISI 316L austenitic steel. The results obtained in the roughness and microhardness measurements, the state of the surface layer, and the tribological properties (ball-on-disc) of the specimens after the peening process were compared to the results obtained for the reference specimen. The tests were carried out with varying parameters of pressure (0.3 MPa, 0.4MPa) and time (30s, 60s). The lowest values of COF (µ=0.576) and wear factor (K=3.95*10-4 mm3N-1m-1) were observed for the surface peened using parameters: 0.4 MPa and 60s. By increasing the time twice, a much lower wear factor can be achieved unlike when increasing the shot peening by 0.1 MPa. Observations of wear traces indicate that abrasive wear is predominant and the transfer of specimen material by countersample is also observed.

5

Analysis of friction and wear processes in an innovative spine stabilization system. Part 1. A study of static and kinetic friction of a metal rod-polymer cord friction joint

Brończyk Anna

Acta of Bioengineering and Biomechanics

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2022

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Vol. 24, no. 1

118--130

EN

This analysis is the first part of research that aims to develop a model of the tribological wear of PE-UHMW cord – biometal rod combination. This type of sliding joint is applied in spine stabilization systems that enable the treatment of early-onset idiopathic scoliosis. Methods: The friction tests included force measurements, followed by the determination of static and kinetic friction coefficients as a function of the number of the performed movement cycles, and static friction coefficient with regards to the string tension force FN in the range of 50–300 N. Additionally, the surface roughness and microscopic observations of the metal rods were made. The friction measurements were carried out at a stabilized temperature T = 38 °C in the presence of distilled water and acidic sodium lactate. Results: The measurements confirmed the impact of both the number of completed movement cycles and the value of the force loaded on the cord on the static friction coefficient. Similar values of kinetic friction force occur for the pairs with the titanium alloys rods, as well as for the pairs with the steel and CoCr rod. The type of lubricant affected the obtained measurement results unevenly: (Ti6Al4V and Ti6Al7Nb – slight impact, steel 316L and CoCrMo – large impact). During microscopic observations, numerous wear products, were visible, including harder than the base material large conglomerates. Conclusions: Susceptibility of polymer fibres results in its increased resistance to wear, but it can be also combined with an increase in wear of the surface of the metal rod.

6

Pitting corrosion behaviour of austenitic stainless-steel coated on Ti6Al4V alloy in chloride solutions

Yamanoglu R., Fazakas E., Ahnia F., Alontseva D., Khoshnaw F.

Advances in Materials Science

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2021

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Vol. 21, nr 2(68)

5--15

EN

This study aims to investigate the influence of adding a coating layer of austenitic stainless steel type 316L on Ti6Al4V alloy on corrosion behaviour. Samples of 316L, Ti6Al4V, and 316L on Ti6Al4V were prepared by hot-press sintering of their powders. The potentiodynamic polarization technique was used to characterize the corrosion behaviour of the samples in 0.9 and 3.5 wt. % NaCl concentrations. The corrosion potential (Ecorr.), current density (icorr) and corrosion rate (CR) of the sintered samples were compared in this study. The results showed that 316L samples had the best corrosion resistance, although micropits were observed on the surface, while Ti6Al4V samples had the lowest. This corrosion behaviour of sintered 316L samples can be interrelated to the existence of a passive layer on stainless steel alloys that can be attacked by chloride ions and causing localized corrosion. In general, the CR values of Ti6Al4V samples coated by 316L were between the 316L and Ti6Al4V samples. The CR values of the samples, in 0.9 wt. % NaCl, did not show significant changes with increasing time, as the CR for 316L values were around 0.003 mm/year, while for Ti6Al4V the CR values changed noticeably from 0.018 mm/year of 0 hr, to 0.015 mm/year for 24 hours. However, the changes were less than that of Ti6Al4V. For 3.5 wt. % NaCl solution, although the same order of CR remained, i.e., the CR values of coated Ti6Al4V samples were between 316L (lowest) and Ti6Al4V (highest), the overall CR values for the samples were higher than 0.9 wt. % NaCl.

7

Optimization and analysis of porosity and roughness in selective laser melting 316L parts

Król M., Mazurkiewicz J., Żołnierczyk S.

Archives of Materials Science and Engineering

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2018

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Vol. 90, nr 1

5--15

EN

Purpose: The investigations have been carried out on 316L stainless steel parts fabricated by Selective Laser Melting (SLM) technique. The study aimed to determine the effect of SLM parameters on porosity, hardness, and structure of 316L stainless steel. Design/methodology/approach: The analyses were conducted on 316L stainless steel parts by using AM125 SLM machine by Renishaw. The effects of the different manufacturing process parameters as power output, laser distance between the point’s melted metal powder during additive manufacturing as well as the orientation of the model relative to the laser beam and substrate on porosity, hardness, microstructure and roughness were analysed and optimised. Findings: The surface quality parts using 316L steel with the assumed parameters of the experiment depends on the process parameters used during the SLM technique as well as the orientation of formed walls of the model relative to the substrate and thus the laser beam. The lowest roughness of 316L SLM parts oriented perpendicularly to the substrate was found when 100 W and 20 μm the distance point was utilised. The lowest roughness for part oriented at 60° relatives to the substrate was observed when 125 W and the point distance 50 μm was employed. Practical implications: Stainless steel is one of the most popular materials used for selective laser sintering (SLM) processing to produce nearly fully dense components from 3D CAD models. Reduction of porosity is one of the critical research issues within the additive manufacturing technique SLM, since one of the major cost factors is the post-processing. Originality/value: This manuscript can serve as an aid in understanding the importance of technological parameters on quality and porosity of manufactured AM parts made by SLM technique.

8

Comparison of Vacuum Sintered and Selective Laser Melted Steel AISI 316L

Brytan Z.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 4

2125--2131

EN

The paper presents the results of the basic mechanical properties determined in the static tensile test, impact un-notched Charpy test and hardness of austenitic stainless steel type 316L produced by two techniques: classical pressing and sintering in a vacuum with rapid cooling and selective laser melting (SLM). In this work fracture surface of Charpy test, samples were studied. The results indicate that application of selective laser melting (SLM) makes it possible to double increase the strength properties of components manufactured from austenitic stainless steel type 316L compared to sintering in a vacuum. Resulted in mechanical properties strongly depend on porosity characteristic and the presence of superficial oxides in the case of sintered steel and the character of observed microstructural defects deriving from non-fully melted powder particles and the formation of voids between subsequently melted pool tracks during the SLM.

9

The Influence of Kinematic Conditions of Slide/Roll Friction on the Wear of PE-UHMW

Kowalewski P., Woźniak F.

Tribologia

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2016

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nr 1

35--43

PL

W pracy opisano badania pary trącej stal 316L–polietylen PE-UHMW podczas ruchu toczno-ślizgowego. Analizie poddano wartości zużycia liniowego płytek polimerowych przy różnych wartościach stosunku prędkości liniowej do obrotowej elementów węzła tarcia. Jako podstawowe parametry kinematyczne w analizowanym węźle przyjęto: prędkość kątową stalowego walca – ω oraz prędkość przesuwu płytki polimerowej vp. W przeprowadzonym eksperymencie dla wszystkich analizowanych przypadków prędkość poślizgu geometrycznego s była stała i wynosiła 25 mm/s. Przyjęcie stałej prędkości poślizgu s przy różnych wartościach prędkości przesuwania się punktu styku vp pozwoliło na wyznaczenie wpływu tego parametru na zużycie liniowe komponentu polimerowego. Wyniki wykazały wpływ prędkości przemieszczania punktu styku vp na wartości zużycia liniowego polietylenu. Eksperyment wykazał zwiększenie wartości zużycia liniowego polimeru w przypadkach skrajnych ruchu toczno-ślizgowego (vp = 0 oraz ω = 0).

EN

The paper describes a study of steel 316L – polyethylene PE-UHMW friction couple during the slip-roll motion. The analysis is focused on the linear wear of polymer plates at various rolling-to-slip ratio values. Kinematic parameters of the friction nodes were angular velocity of the steel cylinder – ω, and the linear speed of the polymer plate – vp. In the experiment, the geometrical slip speeds were constant (s = 25 mm/s for each case). The constant geometrical slip speeds for different values of the plate speed (traverse of the contact point) vp allowed the determination of the influence of that parameter on the linear wear of the polymer component. The research showed the impact of plate speed (the contact point's traverse) vp on the values of the linear wear of the polyethylene, and the polymer's linear wear increase at the extreme ratios of the slip-roll motion (vp = 0, ω = 0).

10

Analysis of the sintering process of 316L – hydroxyapatite composite biomaterials

Szewczyk-Nykiel A., Nykiel M.

Czasopismo Techniczne. Mechanika

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2015

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Y. 112, iss. 3-M

79--92

EN

The 316L-hydroxyapatite biocomposites were produced by the powder metallurgy technology. The properties and microstructure of these materials are affected by the chemical composition of the powders mixture and the sintering temperature. The sintering temperature of 1240°C and hydroxyapatite addition in an amount of 3% of mass obtained the highest density and hardness and smaller open and closed porosity. Hydroxyapatite addition to austenitic stainless steel modified sintering behaviour. During heating the thermal decomposition of hydroxyapatite took place, which led to the formation of a CaO phase. However, phosphorus diffused into the austenitic matrix and was involved in the eutectic transformation.

PL

Kompozyty 316L-hydroksyapatyt zostały wytworzone technologią metalurgii proszków. Właściwości i mikrostruktura badanych materiałów uzależnione są od składu chemicznego mieszanki proszków oraz zastosowanej temperatury spiekania. Temperatura spiekania 1240°C i dodatek hydroksyapatytu w ilości 3% wag. pozwalają uzyskać najwyższą gęstość i twardość oraz najmniejszą porowatość otwartą i zamkniętą. Hydroksyapatyt wpływa na przebieg procesu spiekania stali austenitycznej. Podczas nagrzewania następuje rozkład hydroksyapatytu, który prowadzi do powstania fazy CaO. Natomiast fosfor dyfunduje do osnowy austenitycznej, a następnie bierze udział w przemianie eutektycznej.

11

Spiekane biomateriały kompozytowe AISI 316L-hydroksyapatyt

Szewczyk-Nykiel A., Nykiel M., Kazior J.

Czasopismo Techniczne. Mechanika

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2012

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R. 109, z, 6-M

115--125

PL

Połączenie dobrej biotolerancji hydroksyapatytu z dobrymi własnościami mechanicznymi stali 316L powinno doprowadzić do uzyskania lepszego biomateriału. Kompozyty 316L-hydroksyapatyt zostały wytworzone technologią metalurgii proszków. Mikrostruktura i własności badanych materiałów zależą od składu chemicznego mieszanki proszków oraz zastosowanej temperatury spiekania. Mianowicie temperatura spiekania 1240°C i dodatek hydroksyapatytu w ilości 3% wag. pozwalają uzyskać najlepszą gęstość i twardość spiekom 316L-hydroksyapatyt.

EN

The combinations of good biocompatibility of hydroxyapatite and good mechanical properties of 316L steel should lead to obtain better biomaterial. 316L-hydroxyapatite composites were produced by the PM technology. Microstructure and properties of these materials were affected by chemical composition of powders mixture and sintering temperature. Sintering temperature of 1240°C and hydroxyapatite addition of 3 wt. % provide to obtain the best density and hardness sintered 316L-hydroxyapatite compositions.

12

Charakterystyka biomateriałów kompozytowych typu AISI 316L - hydroksyapatyt

Szewczyk-Nykiel A., Kazior J., Nykiel M.

Czasopismo Techniczne. Mechanika

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2009

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R. 106, z. 2-M

39-44

PL

Celem badań było wytworzenie kompozytów 316L - Hap do zastosowań w medycynie. Połączenie dobrej biotolerancji Hap z dobrymi własnościami mechanicznymi stali 316L powinno doprowadzić do uzyskania lepszego biomateriału. Kompozyty zostały wytworzone technologią metalurgii proszków.

EN

The aim of study is to produce a 316L - Hap composite for medical applications. The combinations of good biocompatibility of Hap and good mechanical properties of 316L steel should lead to obtain better biomaterial. In this work, composites were produced by the PM technology.