Methodology and Installation of the Etching of the Surface Layer from Pipes, Rods and Profiles for the Aim of the Analysis of Residual Stresses

2019 ◽  
Vol 946 ◽  
pp. 79-83
Author(s):  
Georgy V. Shimov
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Pipe Wall ◽  
Thin Surface Layer

The paper presents the design of the etching unit, the experiment procedure to remove a thin surface layer of metal and fixing the elastic discharge of the pipe along its length. The value of elastic discharge is necessary to calculate the residual stresses of a thin surface layer, as well as the distribution of residual stresses of the pipe wall.

scholarly journals Influence of Vibration and Heat Treatment on Residual Stress of a Machined 12%Cr-Steel

2014 ◽  
Vol 996 ◽  
pp. 609-614 ◽  
Author(s):  
Lin Peng Ru ◽  
Johan Moverare ◽  
Pajazit Avdovic ◽  
Annethe Billenius ◽  
Zhe Chen
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Surface Layer ◽  
Stress Relaxation ◽  
Residual Stresses ◽  
Thin Surface Layer ◽  
Microstructural Changes ◽  
Low Level ◽  
Stress Relieving ◽  
Compressive Residual Stresses

In this paper we investigated the influence of vibratory stress relieving technique, which is widely used for stress relaxation of weld and casting components/structure, on machining residual stresses in a ring-component of 12%Cr-steel. It was shown that the employed vibratory treatment, without significantly altering the microstructure, turned the surface layer from tension into compression but retained the compressive residual stresses in the subsurface. In comparison, a stress relieving heat treatment, included as a reference in the study, removed completely the surface tensile residual stresses and reduced the subsurface compressive residual stresses to a low level. Significant microstructural changes in the form of recrystallization also occurred in a thin surface layer of the machining affected zone after the heat treatment.

Influence of Laser Remelting Process on Strain and Residual Stresses in Nodular Iron

2011 ◽  
Vol 681 ◽  
pp. 188-193 ◽  
Author(s):  
Roman Šturm ◽  
Janez Grum
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Laser Beam ◽  
Stress Measurement ◽  
Specimen Surface ◽  
Thin Surface Layer ◽  
Laser Remelting ◽  
Volume Changes ◽  
Workpiece Surface

The present paper deals with residual stress and strain changes in thin flat specimens of nodular cast iron during laser remelting process. In laser remelting process of a workpiece we have used several laser beam passages across the workpiece surface. The state of internal stress in the workpiece changes because of different ways of guiding the laser beam across the workpiece surface, and consequently strain of the workpiece may occur. In the process of gradual remelting of the specimen surface, i.e. during its heating and cooling, volume changes in the specimen surface layer occur due to thermal and microstructural changes. To find out more about volume changes in the thin surface layer of specimens, the latter were monitored by measuring the strain at the lower side of the specimens during and after the remelting process, and also by residual stress measurement in the thin surface layer. The results obtained confirm that the laser remelting process could be successfully optimised on the basis of knowing the residual stresses and the strain generated during the remelting process.

Laser Shock Processing of the Maraging Steel Surface

2007 ◽  
Vol 537-538 ◽  
pp. 655-662 ◽  
Author(s):  
Janez Grum ◽  
Martin Zupančič ◽  
J.L. Ocaña
Keyword(s):  
Surface Layer ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Maraging Steel ◽  
Thin Surface Layer ◽  
Beam Diameter ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Pulse Density ◽  
Shock Processing

Laser Shock Processing (LSP) is a process of laser treating of a surface with a pulsed beam of high power density. The process enables hardening of a thin surface layer; therefore, it is suitable for the improvement of fatigue strength of quality materials. Locally directed mechanical waves produce a considerably increased dislocation density in the thin surface layer, which affects the variations of microhardness and residual stresses. The magnitude and variation of the residual compressive stresses in the surface layer are favourable, which ensures higher fatigue strength. Laser shock processing (LSP) is more exacting than conventional shot peening, but it shows certain advantages such as better control of the surface state, processing of locally limited surfaces and a possibility to produce different transitions between the processed surface and the non-processed one. LSP has so far been tested and efficiently applied to various materials, including maraging steels. Relevant publications often deal with LSP mechanisms and the influence of the process on the dynamic strength of maraging steel, but less frequently the influence of individual characteristics such as the microstructure of matrix and of precipitated phases or residual stresses. The present paper deals with LSP of 12% Ni maraging steel. The material chosen is suitable for the production of complex structural parts and dies for die casting, which require high resistance of the material to thermo-mechanical loads. By means of measurement of the state before and after LSP, the value of the mean roughness Ra, surface defects and the variation of residual stresses in the thin surface layer were determined. After LSP of the surface, the influence of processing parameters such as laser-beam diameter and pulse density per unit of area was established.

Effect of diamond burnishing parameters on the state of the processed surface layer of billets made of high-strength "30ХГСН2А-ВД" steel

2020 ◽  
pp. 82-86
Author(s):  
A.N. Shvetsov ◽  
D.L. Skuratov
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Strain Hardening ◽  
Processing Speed ◽  
Synthetic Diamond ◽  
High Strength ◽  
The State ◽  
Diamond Burnishing

The influence of the burnishing force, tool radius, processing speed and feed on the distribution of circumferential and axial residual strses, microhardness and the depth of strain hardening in the surface layer when pr ssing of "30ХГСН2А-ВД" steel with synthetic diamond "ACB-1" is considered. Empirical dependencies determining these parameters are given. Keywords diamond burnishing, strain hardening depth, circumferential residual stresses, axial residual stresses, microhardness. [email protected], [email protected]

scholarly journals Thermal Effects on Surface and Subsurface Modifications in Laser-Combined Deep Rolling

2021 ◽  
Vol 5 (2) ◽  
pp. 55
Author(s):  
Robert Zmich ◽  
Daniel Meyer
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Thermal Loads ◽  
Deep Rolling ◽  
Mechanical Loads ◽  
Thermomechanical Process ◽  
Compressive Stresses ◽  
New Process ◽  
Negative Effect ◽  
Compressive Residual Stresses

Knowledge of the relationships between thermomechanical process loads and the resulting modifications in the surface layer enables targeted adjustments of the required surface integrity independent of the manufacturing process. In various processes with thermomechanical impact, thermal and mechanical loads act simultaneously and affect each other. Thus, the effects on the modifications are interdependent. To gain a better understanding of the interactions of the two loads, it is necessary to vary thermal and mechanical loads independently. A new process of laser-combined deep rolling can fulfil exactly this requirement. The presented findings demonstrate that thermal loads can support the generation of residual compressive stresses to a certain extent. If the thermal loads are increased further, this has a negative effect on the surface layer and the residual stresses are shifted in the direction of tension. The results show the optimum range of thermal loads to further increase the compressive residual stresses in the surface layer and allow to gain a better understanding of the interactions between thermal and mechanical loads.

Reduction of Residual Stresses in Medium Density Fibreboard. Part 1. Taguchi Analysis

Holzforschung ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 67-72 ◽  
Author(s):  
J. van Houts ◽  
D. Bhattacharyya ◽  
K. Jayaraman
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Internal Bond ◽  
Tensile Modulus ◽  
Thickness Swell ◽  
Subsequent Paper ◽  
Medium Density ◽  
Medium Density Fibreboard ◽  
Taguchi Analysis ◽  
Dissection Method

Summary This paper demonstrates how the Taguchi method of experimental design can be utilised to investigate methods for relieving the residual stresses present in medium density fibreboard (MDF). Panels have been subjected to heat, moisture and pressure, and after equilibration to room conditions, the changes in residual stresses through various layers have been measured using the dissection method. The application of heat and/or moisture has reduced the magnitude of residual stresses while generally the application of pressure has no effect on these stresses. The subsequent paper in this series uses Taguchi analysis to investigate how other board properties such as thickness swell, internal bond strength, surface layer tensile modulus and surface layer tensile strength are affected by the different treatment methods.

Surface Modification Analysis after Shot Peening of AA 7075 in Different States

2013 ◽  
Vol 768-769 ◽  
pp. 519-525 ◽  
Author(s):  
Sebastjan Žagar ◽  
Janez Grum
Keyword(s):  
Residual Stress ◽  
Surface Layer ◽  
Residual Stresses ◽  
Aluminium Alloy ◽  
Shot Peening ◽  
Fatigue Testing ◽  
Stress Profile ◽  
Treatment Conditions ◽  
Stress Profiles ◽  
Compressive Residual Stresses

The paper deals with the effect of different shot peening (SP) treatment conditions on the ENAW 7075-T651 aluminium alloy. Suitable residual stress profile increases the applicability and life cycle of mechanical parts, treated by shot peening. The objective of the research was to establish the optimal parameters of the shot peening treatment of the aluminium alloy in different precipitation hardened states with regard to residual stress profiles in dynamic loading. Main deformations and main residual stresses were calculated on the basis of electrical resistance. The resulting residual stress profiles reveal that stresses throughout the thin surface layer of all shot peened specimens are of compressive nature. The differences can be observed in the depth of shot peening and the profile of compressive residual stresses. Under all treatment conditions, the obtained maximum value of compressive residual stress ranges between -200 MPa and -300 MPa at a depth between 250 μm and 300 μm. Comparison of different temperature-hardened aluminium alloys shows that changes in the Almen intensity values have greater effect than coverage in the depth and profile of compressive residual stresses. Positive stress ratio of R=0.1 was selected. Wöhler curves were determined in the areas of maximum bending loads between 30 - 65 % of material's tensile strength, measured at thinner cross-sections of individual specimens. The results of material fatigue testing differ from the level of shot peening on the surface layer.

scholarly journals Rated definition of degree of cutter coating influence upon parameters of surface layer quality of parts worked

2017 ◽  
Vol 2 (7) ◽  
pp. 20-24
Author(s):  
Вячеслав Безъязычный ◽  
Vyacheslav Bezyazychnyy ◽  
Максим Басков ◽  
Maksim Baskov
Keyword(s):  
Surface Roughness ◽  
Surface Layer ◽  
Residual Stresses ◽  
Layer Surface ◽  
Wear Resistant Coatings ◽  
Cutter Wear ◽  
Definition Of ◽  
Surface Layer Quality ◽  
The Impact

The impact of cutter wear-resistant coatings upon cutting process parameters and characteristics of surface layer quality in the parts worked: residual stresses, a degree and a depth of work hardening of a surface layer, surface roughness is investigated.

FEM Simulation of the Residual Stress in the Machined Surface Layer for High-Speed Machining

2006 ◽  
Vol 315-316 ◽  
pp. 140-144 ◽  
Author(s):  
Su Yu Wang ◽  
Xing Ai ◽  
Jun Zhao ◽  
Z.J. Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Surface Layer ◽  
Residual Stresses ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
High Speed Machining ◽  
Machined Surface ◽  
Cutting Model

An orthogonal cutting model was presented to simulate high-speed machining (HSM) process based on metal cutting theory and finite element method (FEM). The residual stresses in the machined surface layer were obtained with various cutting speeds using finite element simulation. The variations of residual stresses in the cutting direction and beneath the workpiece surface were studied. It is shown that the thermal load produced at higher cutting speed is the primary factor affecting the residual stress in the machined surface layer.

Changes in Residual Stress in Worked Surface Layer of Type 304 Austenitic Stainless Steel Due to Tensile Deformation

2000 ◽  
Vol 123 (1) ◽  
pp. 130-134
Author(s):  
Makoto Hayashi ◽  
Kunio Enomoto
Keyword(s):  
Solid Solution ◽  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Residual Stresses ◽  
Tensile Deformation ◽  
End Mill ◽  
Heat Treated ◽  
304 Austenitic Stainless Steel ◽  
Type 304

Changes in the residual stress in a worked surface layer of type 304 austenitic stainless steel due to tensile deformation were measured by the X-ray diffraction residual stress measuring method. The compressive residual stresses introduced by end-mill, end-mill side cutter, and grinder were easily changed into tensile stresses when the plate specimens were subjected to tensile stress greater than the yield stress of the solid solution heat-treated material. The residual stresses after the tensile deformation depend on the initial residual stresses and the degree of preliminary working. The behavior of the residual stress changes can be interpreted if the surface-worked material is regarded as a composite made of solid solution heat-treated material and work-hardened material.

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