Residual Stress in PVD-Coated Carbide Cutting Inserts - Applications of the sin2ψ and the Scattering Vector Method

2010 ◽  
Vol 638-642 ◽  
pp. 2383-2388 ◽  
Author(s):  
Berend Denkena ◽  
Georg Erkens ◽  
Bernd Breidenstein
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Cutting Tools ◽  
X Ray Diffraction ◽  
Vector Method ◽  
Residual Stress State ◽  
Coated Tool ◽  
Cutting Inserts ◽  
Cohesive Damage ◽  
Coated Carbide

Premature collapse in terms of cohesive damage of PVD-coated carbide cutting tools often results in a time and cost consuming immediate interrupt of the cutting process. It is assumed that the residual stress state of the composite coating – substrate in combination with external loads during tool use is responsible for cohesive damage. The X-ray diffraction methods sin2 and scattering vector are applied for determination of the residual stress depth distribution in the coating and the substrate’s subsurface. Investigations of the residual stress state of commercial PVD-coated carbide cutting tools are presented. It is determined to what extent the single process steps during tool manufacturing are responsible for the final residual stress state of the PVD-coated tool. Furthermore the meaning of the PVD-coating process for the substrate’s residual stress state is investigated. Moreover, possibilities of controlling the residual stress state of the substrate by changing process variables of selected process steps are analyzed.

Residual Stress Gradients in PVD-Coated Carbide Cutting Tools

2006 ◽  
Vol 524-525 ◽  
pp. 607-612 ◽  
Author(s):  
Berend Denkena ◽  
Bernd Breidenstein
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Cutting Tools ◽  
Surface Residual Stress ◽  
Vector Method ◽  
Near Surface ◽  
Residual Stress State ◽  
Coated Tools ◽  
Cohesive Damage ◽  
Coated Carbide

PVD-coated cutting tools show a typical kind of failure in use: cohesive damage, which is believed to be a result of the residual stress state of substrate and coating. As the sin2ψ-technique does not give satisfactory information on near surface residual stress trends of coated tools the scattering vector method was applied to determine residual stress depth distributions of coating and substrate. The results are presented and an attempt for an interpretation is given.

Pre PVD-Coating Processes and their Effect on Substrate Residual Stress in Carbide Cutting Tools

2010 ◽  
Vol 438 ◽  
pp. 17-22 ◽  
Author(s):  
Berend Denkena ◽  
Bernd Breidenstein
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Cutting Tools ◽  
Residual Stress State ◽  
Pvd Coating ◽  
Parameter Variations ◽  
Single Process ◽  
The Stability ◽  
Cohesive Damage ◽  
Coated Cemented Carbide

Cohesive damage of PVD-coated cemented carbide cutting tools is ascribed to the residual stress state of the substrate subsurface. The present paper shows the formation of the substrate residual stress in the process chain as well as the stability of the single process steps referred to the scattering of the residual stress values. Depth resolved residual stress measurements across coating and substrate subsurface show a layer in the substrate, where possibly tensile stress occurs, from where cohesive damage may be initialized during tool use. Results of experiments are presented, where the influence of parameter variations in pre coating processes on the residual stress state is investigated. The characteristics of compressive residual substrate stress during the final PVD-process is presented as well as a correlation between coating and substrate stress.

Residual Stress Development in Laser Machined PVD-Coated Carbide Cutting Tools

2013 ◽  
Vol 768-769 ◽  
pp. 391-397 ◽  
Author(s):  
Bernd Breidenstein ◽  
Christoph Gey ◽  
Berend Denkena
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Machining Process ◽  
Laser Machining ◽  
Residual Stress State ◽  
Stress States ◽  
The Individual ◽  
Coated Carbide

Abstract. There is growing interest in laser machining as an alternative to abrasive processes for creating cutting tool micro geometries. This technology is also suitable for creating micro geometries on cutting edges of superhard cutting tools. The pulsed nanosecond lasers, which are commonly used for this type of application, induce a high thermal load in the tool. This heat is believed to result in tensile residual stresses at the cutting edge surface, which are generally unfavorable for cutting tool performance because of the tendency to crack formation and propagation. Different levels of compressive residual stress exist after each step (sintering, grinding, shot peening, etching and PVD-coating). From investigations of commercial processes for manufacturing PVD-coated carbide cutting tools it is known that the final residual stress state of the carbide subsurface is a result of superposition of the stress states resulting from the individual process steps. In contrast to that, a laser machining process is expected to produce tensile residual stress due to the heat input. The present work describes the influence of a process chain alteration for PVD-coated carbide cutting tools by a laser machining process on the residual stress state in the finished tools.

X-ray diffraction analysis of the residual stress state in PVD TiN/CrN multilayer coatings deposited on tool steel

2005 ◽  
Vol 200 (1-4) ◽  
pp. 165-169 ◽  
Author(s):  
C. Mendibide ◽  
P. Steyer ◽  
C. Esnouf ◽  
P. Goudeau ◽  
D. Thiaudière ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Diffraction Analysis ◽  
Tool Steel ◽  
Multilayer Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Stress State

Residual stress analysis of diamond-coated WC–Co cutting tools: separation of film and substrate information by grazing X-ray diffraction

2013 ◽  
Vol 46 (5) ◽  
pp. 1323-1330 ◽  
Author(s):  
M. Meixner ◽  
M. Klaus ◽  
Ch. Genzel ◽  
W. Reimers
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Cutting Tools ◽  
Chemical Vapour ◽  
Cvd Diamond ◽  
Diamond Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Stress State ◽  
Residual Stress Analysis

Chemical vapour deposition (CVD) of diamond surface layers is an effective way of improving the properties of cemented carbide cutting tools. Inadequate coating adhesion is one of the main issues and it may be affected by the residual stresses of the CVD diamond films. The most common methods for nondestructive residual stress analysis are based on X-ray diffraction. The present paper deals with the particular case of determining the residual stress state of thin CVD diamond layers deposited on cobalt cemented tungsten carbide (WC–Co) substrates. It will be shown that the application of the conventional sin2ψ method might lead to erroneous results, as a result of superimposing diffraction lines originating from cobalt and the diamond coating. An approach to separating information on the substrate and film, based on grazing conditions in the symmetrical Ψ mode of diffraction, is presented. The results, revealing large compressive stresses within the coating, are compared with those obtained by supplementary micro-Raman spectroscopy investigations.

Hydrogen Interaction with Residual Stresses in Steel Studied by Synchrotron X-Ray Diffraction

2013 ◽  
Vol 772 ◽  
pp. 91-95 ◽  
Author(s):  
Eitan Dabah ◽  
Thomas Kannengiesser ◽  
Dan Eliezer ◽  
Thomas Boellinghaus
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
High Energy ◽  
Steel Sample ◽  
Stainless Steel Sample ◽  
X Ray Diffraction ◽  
High Hydrogen ◽  
X Ray ◽  
Residual Stress State

The residual stress state in a material has an important role in the mechanism of cracking, induced or assisted by hydrogen. In this contribution, the beamline EDDI in BESSY II instrument in Berlin was used in order to investigate the influence of hydrogen upon the residual stresses state existing in a Supermartensitic stainless steel sample. The method used for investigating the residual stresses is the “sinus square ψ” method. This method involves the usage of high energy X-ray diffraction in order to measure the residual stress state and magnitude. It was found that hydrogen presence has a significant influence upon the magnitude of the residual stresses, as its value decreases with high hydrogen content. This effect is reversible, as hydrogen desorbs from the sample the residual stress magnitude gains its initial value before hydrogen charging.

scholarly journals Neutron and X-Ray Diffraction Residual Stress Measurements in Aluminium Alloys MIG Welded T-Joints after Friction Stir Processing

2014 ◽  
Vol 996 ◽  
pp. 439-444 ◽  
Author(s):  
João P. Nobre ◽  
António Castanhola Batista ◽  
Joana R. Kornmeier ◽  
José D. Costa ◽  
Altino Loureiro ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stress State ◽  
Friction Stir Processing ◽  
Aluminium Alloys ◽  
X Ray Diffraction ◽  
T Joints ◽  
X Ray ◽  
Friction Stir ◽  
Residual Stress State

Friction Stir Processing (FSP) is a relatively new post-processing technique. Fatigue strength of MIG fillet welds of aluminium alloys can be substantially improved using FSP. Beyond other properties intrinsically tied to fatigue life, especially attention should be paid to the effect of the final residual stress state. In this study the residual stress distribution in T-joints of two aluminium alloys was determined by Neutron and X-ray diffraction. FSP effect on the residual stress state and fatigue life was analysed.

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