Characterization of the Residual Stresses in Plastically Deformed Ferrite-Martensite Steels Using Barkhausen Noise Measurements

2005 ◽  
Vol 500-501 ◽  
pp. 655-662 ◽  
Author(s):  
Xavier Kleber ◽  
Aurélie Hug-Amalric ◽  
Jacques Merlin
Keyword(s):  
Plastic Deformation ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Barkhausen Noise ◽  
Opposite Behavior ◽  
Noise Measurements ◽  
Two Phases ◽  
Noise Signature ◽  
Compressive Residual Stresses

In this work, we show that the measurement of the Barkhausen noise allows the residual stresses in each of the two phases of ferrite-martensite steels to be characterized. We have first studied the effect of a tensile and a compressive stress on the Barkhausen noise signature. We observed that for a ferrite-martensite steel, the application of a tensile stress increases the Barkhausen activity of the martensite and ferrite phases, whereas a compressive one reduces it. In a second time, we induced residual stresses by applying a plastic deformation to ferrite-martensite steels. After a tensile plastic deformation, we observed that (i) compressive residual stresses appear in ferrite, and (ii) tensile residual stresses appear in martensite. An opposite behavior is observed after a compressive plastic deformation. These results show that the Barkhausen noise measurement makes it possible to highlight in a nondestructive way the distribution of the stresses in each of the two phases of a ferrite-martensite steel. This result could be used to characterize industrial Dual- Phases steels that are plastically deformed during mechanical processes.

The Effect of Several Finishing Processes on the Fatigue Resistance of Hole Surfaces

1989 ◽  
Vol 111 (1) ◽  
pp. 71-73 ◽  
Author(s):  
M. O. Lai ◽  
A. Y. C. Nee
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Resistance ◽  
Radial Direction ◽  
Fatigue Loading ◽  
Steel Plates ◽  
Finishing Processes ◽  
Compressive Residual Stresses

This investigation examines the effects of different finishing processes on the fatigue life of premachined holes in Assab 760 steel plates. The finishing processes studied were reaming, ballizing, and emery polishing. A general decrease in fatigue life with increase in surface roughness is observed for all the processes employed. In comparing the different processes, for a constant surface roughness, polishing is generally found to give the longest fatigue life while ballizing, in spite of the greater compressive residual stresses induced on the surface of the finished hole, the shortest. The surprising phenomenon was found to be attributed to the amount of plastic deformation occurred before fatigue loading. For Assab 760 steel, a prestrain in the radial direction of less than about 2.5 percent appeared to reduce the fatigue resistance of the material.

Characterization of residual stresses generated during inhomogeneous plastic deformation

1998 ◽  
Vol 33 (3) ◽  
pp. 243-252 ◽  
Author(s):  
T Lorentzen ◽  
T Faurholdt ◽  
B Clausen ◽  
J Danckert
Keyword(s):  
Plastic Deformation ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Numerical Technique ◽  
Numerical Approach ◽  
Explicit Finite Element ◽  
Numerical Predictions ◽  
Deformation Processes ◽  
Elastic Strains

Residual stresses generated by macroscopic inhomogeneous plastic deformation are predicted by an explicit finite element (FE) technique. The numerical predictions are evaluated by characterizing the residual elastic strains by neutron diffraction using two different ( hkl) reflections. Intergranular residual elastic strains between subsets of grains are predicted numerically and verified by neutron diffraction. Subsequently, the measured residual strain profiles in the test samples are modified by the intergranular strains and compared to the engineering predictions of the FE technique. Results compare well and verify the capability of the numerical technique as well as the possibilities of experimental validation using neutron diffraction. The presented experimental and numerical approach will subsequently be utilized for the evaluation of more complicated plastic deformation processes resembling forming operations.

Analysis of Residual Stress in the Rotational Autofrettage of Thick-Walled Disks

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
S. M. Kamal
Keyword(s):  
Plastic Deformation ◽  
Residual Stresses ◽  
Yield Criterion ◽  
Three Dimensional ◽  
Circular Disk ◽  
Flow Rule ◽  
Plane Stress Condition ◽  
Radial Temperature ◽  
Fem Validation ◽  
Compressive Residual Stresses

Autofrettage is a means of generating compressive residual stresses at the inner side of a thick-walled cylinder or hollow disk by causing nonhomogeneous plastic deformation of the material at the inner side. The presence of residual compressive stresses at the inner region of the cylinder/disk enhance the pressure withstanding capacity, fatigue life and the resistance to stress corrosion cracking of the component. Despite the hydraulic and swage autofrettage are the widely practiced processes in industries, there are certain disadvantages associated with these processes. In view of this, in the recent years, researchers have proposed new methods of achieving autofrettage. Rotational autofrettage is such a recently proposed autofrettage method for achieving the beneficial compressive residual stresses in the cylinders. In the present work, the rotational autofrettage is studied for a thick-walled hollow circular disk. A theoretical analysis of the residual stresses produced in the disk after unloading are obtained assuming plane stress condition, Tresca yield criterion and its associated flow rule. The analysis takes into account the effect of strain hardening during plastic deformation. Further, the effect of residual stresses in the typical SS304 and aluminum disk is studied by subjecting them into three different types of loads viz., internal pressure, radial temperature difference, and rotational speed individually. A three-dimensional (3D) finite element method (FEM) validation of the theoretical stresses during rotational autofrettage of a disk is also presented.

Cylindrical Grinding of Nitrided Steels: Grindability, Specific Energy, Temperatures, Residual Stresses and Fatigue Failure

2014 ◽  
Author(s):  
Jeffrey Badger
Keyword(s):  
Plastic Deformation ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Fatigue Failure ◽  
Specific Energy ◽  
Thermal Effects ◽  
Thermal Model ◽  
Residual Tensile Stress ◽  
Cylindrical Grinding ◽  
Stress Measurements

An investigation was made into plunge and traverse cylindrical grinding of nitrided steels in an industrial case involving premature fatigue failure due to residual stresses. The effect of nitriding on grindability was analyzed via specific-energy measurements. Residual stresses were analyzed, including: (1) compressive, from nitriding, with discussion on how this alters stress measurements in practice; (2) compressive, from plastic deformation from grinding; and (3) tensile, from thermal effects in grinding, including the alteration of the nitriding compressive effect. A thermal model was developed to predict surface temperatures in grinding — which were correlated to residual tensile stress measurements — allowing the reduction of stresses and the elimination of fatigue failure.

Characterization of Metallurgical Transformations in Multi-Phase High Strength Steels by Barkhausen Noise Measurement

2007 ◽  
Vol 539-543 ◽  
pp. 4283-4288
Author(s):  
Aurélie Hug-Amalric ◽  
Xavier Kleber ◽  
Jacques Merlin ◽  
Hélène Petitgand ◽  
Philip Meilland
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Residual Austenite ◽  
Noise Measurement ◽  
Barkhausen Noise ◽  
Dual Phase ◽  
Magnetic Barkhausen Noise ◽  
Noise Measurements ◽  
Multi Phase

The potentialities of using the magnetic Barkhausen noise measurement in characterization of metallurgical transformations have been highlighted in multi-phase High Strength (HS) steels. This kind of steels are composed of different metallurgical constituents, such as ferrite, bainite, martensite or residual austenite. Recently, we found that it was possible to assess the proportion of phases in ferrite-martensite steels and in industrial Dual-Phase steels too. In this work, we show that the Barkhausen noise measurements can be also suitable to follow bainitic transformation in a TRIP steel.

Metrological characterization of the thermomechanical influence of the cross-section of the undeformed chip on the surface properties in turning of the aluminum alloy EN AW-2017

2020 ◽  
Vol 87 (12) ◽  
pp. 777-786
Author(s):  
Thomas Junge ◽  
Thomas Mehner ◽  
Andreas Nestler ◽  
Andreas Schubert ◽  
Thomas Lampke
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Cross Section ◽  
Surface Integrity ◽  
Resultant Force ◽  
Mechanical Loads ◽  
Process Measurement ◽  
The Cross ◽  
Compressive Residual Stresses

AbstractThe surface integrity strongly affects the performance properties of parts. Therefore, it is of great importance to be able to measure and adjust the surface-layer properties during the manufacturing process. In particular, cutting operations are characterized by high mechanical loads and temperature gradients in the area of chip formation. To enable a targeted control of the surface-layer properties, a fundamental comprehension of the interrelationships between the thermomechanical impact and the thereby induced material modification is required. Hence, the subject of this study is to measure the thermomechanical changes during turning of the aluminium alloy EN AW-2017 and find correlations thereof to the surface integrity. In order to achieve a large variation of the thermal and mechanical loads, the feed f (0.04 mm to 0.2 mm) and the depth of cut {a_{\mathrm{p}}} (0.4 mm to 2 mm) are varied over a wide range. The cutting speed {v_{\mathrm{c}}} is kept constant (300 m/min). For the in-process measurement of the temperatures and contact conditions at the interface of the tool and the specimen, a tool-workpiece thermocouple is used. Additionally, the components of the resultant force are measured by a dynamometer. The characterization of the surface layer is performed by the measurement of the residual stresses using X-ray diffraction and supplemented by the determination of the geometrical properties of the machined surface using a stylus measurement instrument. The results show an increase in temperature and the components of the resultant force with the enlargement of the cross-section of the undeformed chip. Due to the temperature gradient, tensile residual stresses are introduced in the tangential direction of the surface layer. Compressive residual stresses occur only in the axial direction and can be correlated with the in-process measurement data by introducing the C-value. Consequently, the calculation of the presence of compressive residual stresses allows for a targeted control of the surface-layer properties during machining.

Characterization of Austempered Ductile Iron Through Barkhausen Noise Measurements

2003 ◽  
Vol 22 (4) ◽  
pp. 127-139 ◽  
Author(s):  
C. D'Amato ◽  
C. Verdu ◽  
X. Kleber ◽  
G. Regheere ◽  
A. Vincent
Keyword(s):  
Ductile Iron ◽  
Austempered Ductile Iron ◽  
Barkhausen Noise ◽  
Noise Measurements

Analysis of the Surface Residual Stress in Grinding Aermet100

2011 ◽  
Vol 704-705 ◽  
pp. 318-324
Author(s):  
Y.Q. Xu ◽  
T. Zhang ◽  
Y.M. Bai
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Thermal Expansion ◽  
Tensile Stress ◽  
Heat Source ◽  
Residual Stresses ◽  
Surface Grinding ◽  
Grinding Process ◽  
Surface Residual Stress ◽  
Abrasive Grains

Grinding induces residual stresses, which can play an important role on the fatigue of the component. In general, residual stresses in a ground surface are primarily generated due to three effects: thermal expansion and contraction during grinding, plastic deformation caused by the abrasive grains of the wheel and phase transformations due to high grinding temperature. It was found that thermal expansion and plastic deformation in the grinding process were the major causes of residual stresses. In this paper, an analysis model for the calculation of residual stresses induced by a surface grinding process on an ultrahigh-strength steel (Aermet100) workpiece is presented. Firstly, the stress distribution induces by thermal expansion was obtained base on the transient heat conduction equation and the thermal properties of Aermet100. All the calculations were based on the moving heat source solution which was modeled as a uniformly distributed, 2D heat source moving across the surface of a half-space, found in Carslaw and Jaeger. The results show that the near surface residual stress is predominantly tensile and that the magnitude of this stress increases with increasing heat flux values. Secondly, the plastic deformation caused by the abrasive grains of the wheel was simulated base on the grain-workpiece interaction. The chip formation process and the material removal mechanisms can be examined using the micro-scale approach. The results show that the residual stress induced by the grinding force itself is generally compressive which is smaller than the residual tensile stress induced by thermal stress. Therefore, the residual stress brought about by grinding operation is generally a tensile stress. This paper offers an insight into the mechanism understanding of thermal and mechanical residual stresses induced by surface grinding. Key words: grinding, residual stress, grain

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