Study on Hardness and Elastic Modulus of Surface Nanostructured 304 Stainless Steel Using Two Mechanical Methods

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Gang Ma ◽  
Xiang Ling
Keyword(s):  
Stainless Steel ◽  
Surface Layer ◽  
Elastic Modulus ◽  
Bulk Material ◽  
Hardened Layer ◽  
304 Stainless Steel ◽  
Nanostructured Surface ◽  
Surface Layers ◽  
Mechanical Methods ◽  
The Impact

Ultrasonic impact treatment (UIT) can be used to create a thin nanostructured surface layer that plays a significant role in enhancing the overall strength, fatigue life, and corrosion resistance of the treated material. The hardness and elastic modulus of surface nanostructured 304 stainless steel treated by UIT have been investigated by nanoindentation and microhardness measurements. The hardness of the top nanostructured surface layer and its elastic modulus are about 38% and 30% higher, respectively, than those of the bulk material in the nanohardness testing. Also, the hardness is increased by about 23% in the Vickers microhardness testing. The nanohardness of the nanostructured surface layers decreases with depth and then trends to stable values. A hardened layer is found in the impact zone and the thickness is approximately 450–500 μm. All results demonstrated that the surface nanocrystallization can effectively enhance the mechanical properties of the 304 stainless steel.

FATIGUE PROPERTIES OF SUS304 STAINLESS STEEL AFTER ULTRASONIC NANOCRYSTAL SURFACE MODIFICATION (UNSM)

2012 ◽  
Vol 06 ◽  
pp. 330-335 ◽  
Author(s):  
K.Y. Zhang ◽  
Y.S. Pyoun ◽  
X.J. Cao ◽  
B. Wu ◽  
R. Murakami
Keyword(s):  
Stainless Steel ◽  
Surface Layer ◽  
Surface Modification ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
304 Stainless Steel ◽  
Test Machine ◽  
Nanostructured Surface ◽  
Surface Residual Stresses

The changing of materials surface properties method always was taken into improving the fatigue strength. In this paper, an ultrasonic nanocrystal surface modification(UNSM) technique was used on the SUS 304 stainless steel to form a nanostructured surface layer with different static load(70N, 90N, 110N, 130N) and the vibration strike number was about 20,000times/mm2. The untreated and different condition specimens fatigue strength was all tested by a dual-spindle rotating bending fatigue test machine. SPring-8(a large synchrotron radiation facility) was used to test the surface nanocrystallization components. The X-ray diffraction (XRD), the scanning electron microscopy (SEM), optical microscope and a micro-Vickers hardness tester (MVK-E3, Akashi) were separately used to get the surface residual stresses, fracture surface after fatigue testing, metallographic structure and the microhardness of the nanostructured surface layer. The result showed that martensite transformation took place on the surface of specimens, the surface residual stresses had only a small increase and some cracks occurred between the martensite layer and the austenite layer, but the fatigue strength of 90N improved 81%.

scholarly journals Selected Properties of the Surface Layer of C45 Steel Parts Subjected to Laser Cutting and Ball Burnishing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3429 ◽  
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Laser Cutting ◽  
Experimental Studies ◽  
Hardened Layer ◽  
Ball Burnishing ◽  
Absolute Value ◽  
The Impact ◽  
Compressive Residual Stresses

In this article, we report the results of experimental studies on the impact of ball burnishing parameters on the roughness, microstructure and microhardness of the surface layer of laser-cut C45 steel parts. We also analysed the distribution of residual stresses generated in the surface layer of these parts. Laser-cut parts often require finishing to improve the quality of their surface. The tests performed in this study were aimed at assessing whether ball burnishing could be used as a finishing operation for parts of this type. Ball burnishing tests were performed on an FV-580a vertical machining centre using a mechanically controlled burnishing tool. The following parameters were varied during the ball burnishing tests: burnishing force Fn, path interval fw and the diameter of the burnishing ball dn. Ball burnishing of laser-cut C45 steel parts reduced the surface roughness parameters Sa and Sz by up to 60% in relation to the values obtained after laser cutting. Finish machining also led to the reorganization of the geometric structure of the surface, resulting in an increase in the absolute value of skewness Ssk. This was accompanied by an increment in microhardness (maximum microhardness increment was ΔHV = 95 HV0.05, and the thickness of the hardened layer was gh = 40 µm) and formation of compressive residual stresses in the surface layer.

Effects of Laser Shock Processing on Corrosion Properties of 304 Stainless Steel

2010 ◽  
Vol 426-427 ◽  
pp. 109-113
Author(s):  
De Jun Kong ◽  
Hong Miao ◽  
A.P. Hu
Keyword(s):  
Aqueous Solution ◽  
Residual Stress ◽  
Stainless Steel ◽  
Stress Corrosion ◽  
Compressive Residual Stress ◽  
Hardened Layer ◽  
304 Stainless Steel ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Corrosion Properties

The surface of 304 stainless steel was processed by laser shock wave, its surface micro-structures were observed with SEM, and residual stresses on its surface were measured with X-ray diffraction (XRD) stress tester, and the production mechanism of residual stress was analyzed. The experiment of stress corrosion in 25% NaCl aqueous solution was finished, the crack sensitivity of stress corrosion in NaCl aqueous solution was researched, and the effects of LSP on stress corrosion resistance were analyzed. The results shown that the refined hardened-layer is acquired on the surface of 304 stainless steel by LSP, and compressive residual stress has greatly increased, which improve availably the performances of stress corrosion resistant. The time of appearing cracks is inverse ratio with compressive residual stress, and LSP decreases effectively its stress corrosion cracks.

scholarly journals Experimental and Numerical Investigations on Microcoining of Stainless Steel 304

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Gap-Yong Kim ◽  
Muammer Koç ◽  
Jun Ni
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Bulk Material ◽  
High Strength ◽  
304 Stainless Steel ◽  
Feature Size ◽  
Stainless Steel 304 ◽  
Metallic Parts ◽  
Type 304 ◽  
Type 304 Stainless Steel

Increasing demands for miniature metallic parts have driven the application of microforming in various industries. Only a limited amount of research is, however, available on the forming of miniature features in high strength materials. This study investigated the forming of microfeatures in Type 304 stainless steel by using the coining process. Experimental work was performed to study the effects of workpiece thickness, preform shape, grain size, and feature size on the formation of features ranging from 320μmto800μm. It was found that certain preform shapes enhance feature formation by allowing a favorable flow of the bulk material. In addition, a flow stress model for Type 304 stainless steel that took into consideration the effects of the grain and feature sizes was developed to accurately model and better understand the coining process. Weakening of the material, as the grain size increased at the miniature scale, was explained by the Hall–Petch relationship and the feature size effect.

A New Bilayer Continuum Model Based on Gurtin-Murdoch and Consistent Couple-Stress Theories for Stability Analysis of Beam-Type Nanotweezers

2016 ◽  
Vol 33 (2) ◽  
pp. 137-146 ◽  
Author(s):  
M. Keivani ◽  
A. Koochi ◽  
M. Abadyan
Keyword(s):  
Surface Layer ◽  
Governing Equation ◽  
Couple Stress ◽  
Strain Energy ◽  
Continuum Model ◽  
Mechanical Stability ◽  
Bulk Material ◽  
Beam Type ◽  
External Forces ◽  
The Impact

AbstractNano-scale beams might not be considered uniform isotropic since the energy of the surface layer and microstructure of the bulk part highly affect the mechanical characteristics of the beams. Herein, the impact of the energy of the surface layer and the microstructure of the bulk on the mechanical stability of beam-type nanotweezers are investigated. A new bilayer continuum model has been developed which incorporates the strain energy of the surface atoms as well as the microstructure-dependent strain energy of the bulk material. The recently-developed consistent couple stress elasticity (CCSE) in combination with the Gurtin-Murdoch surface theory is applied to derive the governing equation. The nonlinear governing equation was solved using numerical generalized differential quadrature (GDQ). Effects of various parameters including characteristics of the surface layer, microstructure of the bulk and external forces on the static and dynamic stability threshold of the nanostructure are demonstrated.

scholarly journals Study of the Mechanical Properties of a Nanostructured Surface Layer on 316L Stainless Steel

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
F. C. Lang ◽  
Y. M. Xing ◽  
J. Zhu ◽  
Y. R. Zhao
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Surface Layer ◽  
Electron Microscope ◽  
316L Stainless Steel ◽  
Nanostructured Surface ◽  
Transmission Electron ◽  
Tensile Process ◽  
The Matrix ◽  
Reverse Analysis

A nanostructured surface layer (NSSL) was generated on a 316L stainless steel plate through surface nanocrystallization (SNC). The grains of the surface layer were refined to nanoscale after SNC treatment. Moreover, the microstructure and mechanical properties of NSSL were analyzed with a transmission electron microscope (TEM) and scanning electron microscope (SEM), through nanoindentation, and through reverse analysis of finite element method (FEM). TEM results showed that the grains in the NSSL measured 8 nm. In addition, these nanocrystalline grains took the form of random crystallographic orientation and were roughly equiaxed in shape. In situ SEM observations of the tensile process confirmed that the motions of the dislocations were determined from within the material and that the motions were blocked by the NSSL, thus improving overall yielding stress. Meanwhile, the nanohardness and the elastic modulus of the NSSL, as well as those of the matrix, were obtained with nanoindentation technology. The reverse analysis of FEM was conducted with MARC software, and the process of nanoindentation on the NSSL and the matrix was simulated. The plastic mechanical properties of NSSL can be derived from the simulation by comparing the results of the simulation and of actual nanoindentation.

Macro-Residual Stress in 304 Stainless Steel Coated with ZrO2-CeO2 Thin Films by Sol-Gel Process

2007 ◽  
Vol 336-338 ◽  
pp. 2649-2651 ◽  
Author(s):  
Xin Gang Yu ◽  
Lan Yun Liu ◽  
Yan Bin Zuo ◽  
Lin Jiang Wang ◽  
Hong Wen Ma ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Steel Substrate ◽  
Substrate Surface ◽  
Sol Gel ◽  
Dip Coating ◽  
Metal Substrate ◽  
304 Stainless Steel ◽  
Sol Gel Process

X-ray diffraction (XRD) method to measure the residual stress existing in the metal substrate surface layer was introduced and the sol-gel ZrO2-CeO2 thin film was successfully prepared on SUS304 stainless steel substrate by dip-coating process. The macro residual stress existing in metal substrate was analyzed by XRD. It turns out that the compressive stress existing in the metal substrate surface layer increases with the increase of heat-treated temperature. Based on the above study, colored stainless steels of high quality were prepared by sol-gel process.

scholarly journals A Comparative Study of Corrosive-Erosive Effects at AISI D3 Steel, 304 Stainless Steel and CrN/AlN Material

2012 ◽  
Vol 6 (1) ◽  
pp. 14-21 ◽  
Author(s):  
J. C. Caicedo ◽  
G. Cabrera ◽  
H. H. Caicedo ◽  
W. Aperador
Keyword(s):  
Stainless Steel ◽  
Physical Vapor Deposition ◽  
Ph Value ◽  
Impact Angle ◽  
304 Stainless Steel ◽  
Test Machine ◽  
Erosion Processes ◽  
Coated Materials ◽  
The Impact ◽  
Aisi D3 Steel

Corrosive-erosive effect on AISI D3 steel, 304 stainless steel and CrN/AlN coating in aqueous NaCl slurries was studied. CrN/AlN multilayer films with a thickness of 3 µm and bilayer period of Λ = 60 nm (50 bilayers) were obtained by using the physical vapor deposition (PVD) technique (magnetron sputtering). The corrosion-erosion experiments were performed in a test machine in which the impingement velocity, impact angle, concentration of solids and pH of the solution were controlled. Polarization curves were simultaneously obtained to correlate the electrochemical effects to the erosive wear mechanisms. The slurry used consists of silica particles suspended in a mixture of acid solution and 3.5% NaCl, with a pH value of 5.6. Electrochemical results showed the best corrosion resistance for 304 stainless steels. Additionally, the surface analysis by SEM micrograph revealed formation of cracks in CrN/AlN multilayers coating and plastic deformation in both steel substrates (AISI D3 steel, 304 stainless steel), especially when the mean impact angle is a critical value of 90°. Measurements of critical and passive current densities showed that the behavior of coated materials differed depending on the substrate that is used. Nonetheless, in a general way, by increasing the impact angle and by changing its incidence from normal to grazing, it led to a resistance to corrosion-erosion processes.

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