scholarly journals Effect of Surface Roughness on Oxidation Resistance of Stainless Steel AISI 316Ti During Exposure at High Temperature

2020 ◽  
Vol 29 (12) ◽  
pp. 8060-8069
Author(s):  
Wojciech J. Nowak
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Oxidation Resistance ◽  
Surface Preparation ◽  
Surface Region ◽  
Lower Surface ◽  
Near Surface ◽  
Steel Aisi ◽  
Kinetics Of ◽  
Effect Of Surface

AbstractIn the present work, the influence of surface roughness on oxidation kinetics of AISI 316Ti stainless steel and its consequences in term of oxidation resistance were investigated. Namely, the effect of surface roughness on oxidation resistance was evaluated during different types of cyclic oxidation tests at 900 and 1000 °C. The obtained results revealed that alloy possessing higher surface roughness showed longer lifetime compared to that with lower surface roughness. It was also found that more severe cyclic conditions suppressed the positive effect of surface roughness on sample’s lifetime. The better oxidation resistance of rougher alloy was correlated with suppressed formation of Fe-rich nodules on ground surfaces and explained by the combined effect of introduced defects in the near-surface region and possible increase in residual stresses caused by mechanical surface preparation.

scholarly journals Control of kinetics of plasma assisted nitriding process of Ni-base alloys by substrate roughness

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Wojciech J. Nowak
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Surface Preparation ◽  
Substrate Roughness ◽  
Grit Blasting ◽  
Process Kinetics ◽  
Responsible Mechanism ◽  
Complex Chemistry ◽  
Kinetics Of ◽  
Effect Of Surface

AbstractThe present study investigated the effect of surface roughness on plasma assisted nitriding (PAN) process kinetics of Ni-base alloys. Two model alloys, namely Ni-10Cr and Ni-14Cr-4Al (wt.%) and commercial Rene 80, were examined. To elucidate the effect of surface roughness on nitriding kinetics, three methods of surface preparation were used, (1) polishing up with 1 μm diamond suspension, (2) grinding up to 220 grit sand-paper, and (3)grit blasting. The samples from each type of material were nitrided under the same conditions and investigated after processing. It was found that increase in roughness results in decreasing nitriding kinetics. The decrease of nitriding kinetics depends on alloy chemical composition, namely more complex chemistry resulted in smaller decrease of kinetics. Moreover, grit-blasting was found to be an improper method for surface preparation for PAN. The responsible mechanism for the effect of surface roughness on PAN kinetics of Ni-base alloys was proposed.

Initiation and Growth of Short Cracks during Cycling in an Aged Superduplex Stainless Steel

2011 ◽  
Vol 465 ◽  
pp. 411-414 ◽  
Author(s):  
M. Balbi ◽  
S. Hereñú ◽  
Ingrid Proriol Serre ◽  
Jean Bernard Vogt ◽  
A.F. Armas ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Tensile Axis ◽  
Surface Region ◽  
Aged Condition ◽  
Exponential Behavior ◽  
Near Surface ◽  
Short Cracks ◽  
Superduplex Stainless Steel ◽  
Kinetics Of

The kinetics of short crack growth during cycling has been studied in a superduplex stainless steel in aged condition. After few cycles, slip lines appear distributed in both phases but the preferred phase for microcrack nucleation is the ferrite. Contrary to the exponential behavior observed in the as-received material, the growth rate of microcracks in aged condition follows a rather linear law. Internal dislocation structures were studied in the near surface region; microbands that sometimes extend over several grains were found at approximately 45º of the tensile axis on ferrite grains. The origin of the microbands has been analyzed and correlated with the microcracks.

The Effect of Surface Preparation on Surface Damage and Sigma Formation in Duplex Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 432-437
Author(s):  
Rebecca L. Higginson ◽  
Michael Cenci ◽  
Matthew Rowlett ◽  
Vladislav Kornienko ◽  
Mark A.E. Jepson
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Low Temperature ◽  
Surface Finish ◽  
Stainless Steels ◽  
Surface Preparation ◽  
Surface Region ◽  
Surface Damage ◽  
Nucleation And Growth ◽  
Effect Of Surface

Sigma formation in duplex stainless steels is known to be detrimental to the mechanical properties of the material and limits the alloys to low temperature applications. In this paper, the surface damage caused by grinding on different grit sizes or polishing, is assessed using EBSD. The surface finish is then related to the depth of sigma formation in the surface region with a quantification of how the surface finish effects the sigma nucleation and growth. Finally, the effect of surface finish and sigma formation on the oxidation characteristics of the material is considered.

scholarly journals Consequences of Different Mechanical Surface Preparation of Ni-Base Alloys during High Temperature Oxidation

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3529
Author(s):  
Wojciech J. Nowak ◽  
Krzysztof Siemek ◽  
Kamil Ochał ◽  
Barbara Kościelniak ◽  
Bartek Wierzba
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
High Temperature Oxidation ◽  
Surface Preparation ◽  
Optical Emission ◽  
Surface Region ◽  
Emission Spectrometry ◽  
Air Oxidation ◽  
Temperature Oxidation ◽  
Near Surface

The influence of surface roughness on its high temperature oxidation for an Ni-base superalloy was studied using laser profilometry, atomic force microscopy, mass change measurements, glow-discharge optical emission spectrometry, scanning electron microscopy, X-ray diffraction, and positron annihilation methods. The isothermal and cyclic air oxidation tests were performed at 1000 °C and showed dependence of oxidation behavior on surface roughness. Smoother surfaces oxidation resulted in the formation of a multilayered oxide scale consisting of NiO, Cr2O3, and internally oxidized Al2O3 while a rougher surface formed protective Al2O3 scale. The factors responsible for different oxidation behaviors were determined as higher concentration of vacancies and increased residual stresses in the near-surface region of studied alloys.

Effect of Microstructure on the Dissolution Kinetics of Copper Thin Films in Dilute Aqueous Solutions of Cupric Chloride

1993 ◽  
Vol 323 ◽  
Author(s):  
L. Harper Walsh ◽  
N. B. Feilchenfeld ◽  
J. A. Schwarz
Keyword(s):  
Grain Size ◽  
Grain Orientation ◽  
Dissolution Kinetics ◽  
Surface Region ◽  
Practical Method ◽  
Reaction Rates ◽  
Near Surface ◽  
Dilute Aqueous Solutions ◽  
Microelectronics Industry ◽  
Kinetics Of

ABSTRACTMicrostructural differences in copper deposited by four techniques commonly used in the microelectronics industry were previously reported. [1] The reaction rates were predicted using either grain size or grain orientation as the dominant microstructure characteristic. A practical method to monitor copper speciation was developed.[2] This technique was used to measure the reaction rates for the different copper films under two different etching conditions. The results are explained using grain size, grain orientation and near surface region composition.

Prediction of machining performance using RSM and ANN models in hard turning of martensitic stainless steel AISI 420

2019 ◽  
Vol 233 (13) ◽  
pp. 4439-4462 ◽  
Author(s):  
Abderrahmen Zerti ◽  
Mohamed Athmane Yallese ◽  
Oussama Zerti ◽  
Mourad Nouioua ◽  
Riad Khettabi
Keyword(s):  
Neural Network ◽  
Surface Roughness ◽  
Artificial Neural Network ◽  
Stainless Steel ◽  
Response Surface Methodology ◽  
Martensitic Stainless Steel ◽  
Machining Parameters ◽  
Steel Aisi ◽  
Artificial Neural ◽  
Stainless Steel Aisi

The purpose of this experimental work is to study the impact of the machining parameters ( Vc, ap, and f) on the surface roughness criteria ( Ra, Rz, and Rt) as well as on the cutting force components ( Fx, Fy, and Fz), during dry turning of martensitic stainless steel (AISI 420) treated at 59 hardness Rockwell cone. The machining tests were carried out using the coated mixed ceramic cutting-insert (CC6050) according to the Taguchi design (L25). Analysis of the variance (ANOVA) as well as Pareto graphs made it possible to quantify the contributions of ( Vc, ap, and f) on the output parameters. The response surface methodology and the artificial neural networks approach were used for output modeling. Finally, the optimization of the machining parameters was performed using desirability function (DF) minimizing the surface roughness and the cutting forces simultaneously. The results indicated that the roughness is strongly affected by the feed rate ( f) with contributions of (80.71%, 80.26%, and 81.80%) for ( Ra, Rz, and Rt) respectively, and that the depth of cut ( ap) is the factor having the major influence on the cutting forces ( Fx = 53.76%, Fy = 50.79%, and Fz = 65.31%). Furthermore, artificial neural network and response surface methodology models correlate very well with experimental data. However, artificial neural network models show better accuracy. The optimum machining setting for multi-objective optimization is Vc = 80 m/min, f = 0.08 mm/rev and ap = 0.141 mm.

Comparative Analysis on Wiper and Standard Tools in Dry Finish Turning of Martensitic Stainless Steel AISI 420

2013 ◽  
Vol 845 ◽  
pp. 765-769 ◽  
Author(s):  
Guilherme Cortelini Rosa ◽  
André J. Souza ◽  
Flávio J. Lorini
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Martensitic Stainless Steel ◽  
Cutting Parameters ◽  
Machining Process ◽  
Finish Turning ◽  
Aisi 420 ◽  
Steel Aisi ◽  
Stainless Steel Aisi

Machining performance consists to associate the optimal process and cutting parameters and maximum material removal rate with the most appropriate tool while controlling the machined surface state. This work verifies the influence of standard and wiper cutting tools on generated surface roughness and residual stress in dry finish turning operation of the martensitic stainless steel AISI 420 in a comparative way. Tests are conducted for different combinations of tool nose geometry, feed rate and depth of cut being analyzed through the Design of Experiments regarding to surface roughness parametersRaandRt. Moreover, the formation of residual stresses in the material (using the technique of X-Ray Diffraction) was evaluated after the machining process for these two cutting geometries and thereafter the result was compared between them. An ANOVA is performed to clarify the influence of cutting parameters on generated surface roughness, which outputs inform that cutting tool geometry is the most influent onRaandRt. It is concluded that analyzed wiper inserts present low performance for low feed rates. Regarding the analysis of the residual stresses it can be stated that for standard and wiper tools the values collected show that for finish turning the compression stresses were found. It can be observed that the greatest amount of compressive stress has been found for the standard tool.

Surface Roughness and Initial Pressure Effect on Superplastically Carburized Duplex Stainless Steel

2010 ◽  
Vol 297-301 ◽  
pp. 227-232 ◽  
Author(s):  
Sharidah Azuar Abdul Azis ◽  
Iswadi Jauhari ◽  
Nik Rozlin Nik Masdek ◽  
Nor Wahida Ahamad ◽  
Hiroyuki Ogiyama
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Surface Hardness ◽  
Direct Interaction ◽  
Initial Pressure ◽  
Pressure Effects ◽  
Superplastic Material ◽  
Coarse Microstructure ◽  
Effect Of Surface

Superplastic carburizing (SPC) is a carburizing process that combines carburizing with superplastic deformation. Since SPC involves direct interaction between the superplastically deformed surface and the solid carbon medium, the effect of surface roughness on the process cannot be disregarded. This paper presents the study of surface roughness and initial pressure effects on superplastic carburizing of duplex stainless steel (DSS). SPC was conducted under four different surface roughness (Ra) conditions of 0.9, 0.3, 0.1 and 0.03 μm. The microstructure, surface hardness, and carburized layer thickness were studied. Comparisons were also done on non-superplastic material which has a coarse microstructure. The results showed that the surface roughness strongly affected the properties of the superplastically carburized duplex stainless steel while its effects on the non-superplastic material were not that obvious.

Sign in / Sign up

Export Citation Format

Share Document