Bright plasma nitriding of ferritic steel with several alloying elements

2002 ◽  
Vol 750 ◽  
Author(s):  
J.-D. Kamminga ◽  
C. Kwakernaak ◽  
G. C. A. M. Janssen
Keyword(s):  
Experimental Data ◽  
Tool Steel ◽  
Ferritic Steel ◽  
Plasma Nitriding ◽  
Experimental Results ◽  
Alloying Elements ◽  
Iron Nitrides ◽  
Nitrogen Flux ◽  
Nitriding Time ◽  
Depth Profiles

ABSTRACTHot work tool steel was plasma nitrided in a PVD apparatus. Phases occurring and nitrogen depth profiles were assessed for the nitrided specimens. In all cases bright nitriding was achieved. Increasing the nitriding time from 15 to 120 min yielded a nitriding depth increasing from about 15 to 35 μm, whereas the nitrogen flux decreased from 8.0 to 5.5 × 10-7 kg s-1m-2. Results from an existing model, predicting nitrogen depth profiles due to plasma nitriding, did not accurately describe the experimental data. Therefore the existing model cannot be used straightforwardly to predict the formation of iron nitrides. The discrepancies of model results and experimental results are discussed in view of the assumptions underlying the model for plasma nitriding.

Microstructural and Tribological Characterization of Atmospheric Plasma-Nitrided HS6-5-2C Tool Steel

2014 ◽  
Vol 698 ◽  
pp. 345-350
Author(s):  
Yana Lizunkova ◽  
Andrey Tyurin ◽  
Thomas Hassel
Keyword(s):  
Tool Steel ◽  
Plasma Nitriding ◽  
Research Work ◽  
Base Material ◽  
Atmospheric Plasma ◽  
Nitriding Process ◽  
Iron Nitrides ◽  
Surface Zone ◽  
Atmospheric Conditions ◽  
Stage Of Development

The nitriding process is well known as a method to improve wear, strength and corrosion characteristics of materials surface. The Institute of Materials Science of Leibniz Universität Hannover is on a stage of development of a new nitriding process under atmospheric conditions. The main purpose of the research work is formation of a nitrided layer on the locally loaded areas of a tool (e.g. forging die) under atmospheric conditions to increase wear resistance and durability of operating tools. Nitride layers were generated on the tool steel HS6-5-2C using the transmitted plasma arc. After atmospheric plasma nitriding the samples were investigated using optical microscopy, transmission electron microscopy (TEM), X-Ray diffraction (XRD) and microhardness testing techniques. It has been revealed that the modified zone thickness after atmospheric plasma nitriding reaches 200 μm. TEM and XRD analysis have shown that new phases corresponding to iron nitrides were formed in the surface zone. Microhardness of the surface layer is increased by 10% and friction coefficient has been reduced by approximately 50% in comparison with base material.

Analysis and Prediction of Residual Stresses in Nitrided Tool Steel

2011 ◽  
Vol 681 ◽  
pp. 352-357 ◽  
Author(s):  
Bojan Podgornik ◽  
Vojteh Leskovšek ◽  
Miha Kovačič ◽  
Joze Vižintin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Fatigue Resistance ◽  
Tool Steel ◽  
Plasma Nitriding ◽  
Near Surface ◽  
Stress Evaluation ◽  
Nitriding Time ◽  
Precise Knowledge ◽  
Steel Increase

Plasma nitriding is a thermo-chemical process of high importance for engineering components, which through generation of near-surface compressive residual stresses significantly improves wear and fatigue resistance. A precise knowledge of the level and distribution of residual stresses that exist in surface engineered components is necessary for accurate prediction of a component’s fatigue resistance. However, measurement of residual stress is not always possible, especially in the case of industrial tools and dies. Therefore, other methods for residual stress evaluation and prediction are required by industry. Results of this investigation show that residual stress level and depth in plasma nitrided tool steel increase by nitriding time and temperature. On the other hand, experimental data show that residual steel distribution in plasma nitrided tool steels can be determined on the basis of microhardness depth distribution.

Adhesion Strength between D.C. Plasma Nitrided Steels and CrN Films

2006 ◽  
Vol 118 ◽  
pp. 265-268
Author(s):  
Kyouji Kondo ◽  
Kaoru Ikenaga ◽  
Yoshiyuki Funaki ◽  
Hirotsugu Takeuchi
Keyword(s):  
Wear Resistance ◽  
Critical Load ◽  
Adhesion Strength ◽  
Tool Steel ◽  
Ceramic Coating ◽  
Plasma Nitriding ◽  
Nitriding Time ◽  
Crn Coating ◽  
Ceramic Film

The hard ceramic film made by PVD is used to increase the life and wear resistance of tools and dies. The adhesion strength between the ceramic film and surface of steels is important in ceramic coating of tools and dies. We investigated the adhesion strength between nitrided tool steel for dies SKD61 (JIS) and CrN film. The steel was plasma nitrided with 20 vol% N2 - H2 gas, and coated with CrN by means of PVD of HCD type. Thicknesses of the CrN films are 1 - 6 μm. Plasma nitriding time and thickness of the CrN films was examined to investigate adhesion strength between the CrN film and the steel. Maximum critical load value 55N at nitriding time 7,200 sec was obtained from the CrN coating on the surface of plasma nitrided SKD61

scholarly journals The Anisotropic Stress-Induced Diffusion and Trapping of Nitrogen in Austenitic Stainless Steel during Nitriding

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1319
Author(s):  
Arvaidas Galdikas ◽  
Teresa Moskalioviene
Keyword(s):  
Driving Force ◽  
Plasma Nitriding ◽  
Austenitic Stainless Steels ◽  
Experimental Results ◽  
Rate Equations ◽  
Nitriding Time ◽  
Crystalline Orientation ◽  
Stress Induced Diffusion ◽  
Good Agreement ◽  
Trapping Sites

Plasma nitriding of austenitic stainless steels at moderate temperatures is considered in the presented work. The anisotropic aspects of stress-induced diffusion and influence of nitrogen traps are investigated by kinetic modeling based on rate equations. The model involves diffusion of nitrogen in the presence of internal stress gradients induced by penetrating nitrogen as the next driving force of diffusion after the concentration gradient. The diffusion equation takes into account the fact that nitrogen atoms reside in interstitial sites and in trapping sites. Stress-induced diffusion has an anisotropic nature and depends on the crystalline orientation while trapping–detrapping is isotropic. The simulations are done considering the synergetic effects of both mechanisms and analyzing the properties of both processes separately. Theoretical curves are compared with experimental results taken from the literature. Good agreement between simulated and experimental results is observed, and gives the possibility to find real values of parameters needed for calculations. The nitrogen depth profile shapes, the dependences of nitrogen penetration on nitriding time and on diffusivity, are analyzed considering crystalline orientation of steel single crystal.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

A Technique for the Laboratory Determination of Recirculation in Single Needle Dialysis

1993 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
N.A. Hoenich ◽  
P.T. Smirthwaite ◽  
C. Woffindin ◽  
P. Lancaster ◽  
T.H. Frost ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Results ◽  
New Technique ◽  
Treatment Efficiency ◽  
Single Lumen ◽  
Theoretical Predictions ◽  
Lumen Catheter ◽  
A New Technique

Recirculation is an important factor in single needle dialysis and, if high, can compromise treatment efficiency. To provide information regarding recirculation characteristics of access devices used in single needle dialysis, we have developed a new technique to characterise recirculation and have used this to measure the recirculation of a Terumo 15G fistula needle and a VasCath SC2300 single lumen catheter. The experimentally obtained results agreed well with those established clinically (8.5 ± 2.4% and 18.4 ± 3.4%). The experimental results have also demonstrated a dependence on access type, pump speeds and fistula flow rate. A comparison of experimental data with theoretical predictions showed that the latter exceeded those measured with the largest contribution being due to the experimental fistula.

Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers

2009 ◽  
Author(s):  
Farrokh Zarifi-Rad ◽  
Hamid Vajihollahi ◽  
James O’Brien
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Axial Flow ◽  
Experimental Results ◽  
Scale Model ◽  
Data Set ◽  
Pressure Profiles ◽  
Scale Models ◽  
Inlet Conditions

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.

Effect of RF plasma nitriding time on microhardness and corrosion resistance of 304 stainless steel

1992 ◽  
Vol 59 (3-4) ◽  
pp. 253-260 ◽  
Author(s):  
M.M. Ibrahim ◽  
F.M. El-Hossary ◽  
N.Z. Negm ◽  
M. Abed ◽  
R.E. Ricker
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Plasma Nitriding ◽  
304 Stainless Steel ◽  
Rf Plasma ◽  
Nitriding Time

Heats of mixing of binary mixtures of pyridine base with n-alkane

1988 ◽  
Vol 66 (7) ◽  
pp. 1625-1627 ◽  
Author(s):  
Teresa Kasprzycka-Guttman ◽  
Juan H. Vera
Keyword(s):  
Experimental Data ◽  
Binary Mixtures ◽  
Experimental Results ◽  
Pyridine Base ◽  
Heats Of Mixing

Heats of mixing of 2,4-lutidine and 2,4,6-collidine with n-alkanes were measured at 293.15 K using an isothermal dilution calorimeter. Experimental results were fitted with a Redlich–Kister polynomial. Experimental data and coefficients for the Redlich–Kister polynomials are reported.

scholarly journals Combined Use of Surface Texturing, Plasma Nitriding and DLC Coating on Tool Steel

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 201
Author(s):  
Elisangela Aparecida dos Santos de Almeida ◽  
Julio Cesar Giubilei Milan ◽  
César Edil da Costa ◽  
Cristiano Binder ◽  
José Daniel Biasoli de Mello ◽  
...  
Keyword(s):  
Surface Topography ◽  
Tool Steel ◽  
Photoelectron Spectroscopy ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Multilayer Coating ◽  
Surface Texturing ◽  
X Ray ◽  
Dlc Coating ◽  
Hard Chrome

In cold rolling, a textured roll can be used to imprint a desired surface topography onto the sheet during rolling. This work proposes the use of diamond-like carbon (DLC) coatings to protect the surface topography of the rolls in replacement of the carcinogenic hard chrome. For that, hydrogenated amorphous carbon (a-C:H) was deposited on plasma nitrided tool steel, both for ground and textured specimens. Changes in surface topography due to DLC coating were assessed using a confocal microscope. Coating adhesion was evaluated using the method VDI 3198. The specimens were characterized using X-ray diffraction (XRD), microhardness test and scanning electron microscopy (SEM). The coating was characterized using Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). The results showed a soft multilayer coating consisting of a plasma nitrided layer for load support, a Si-rich interlayer to improve adhesion and an a-C:H top layer. DLC deposition reduced the roughness of the textured specimens. The coating resulted in relatively stable friction and good durability, with small damage and negligible wear even under dry sliding.

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