Causes of residual stresses during machining of workpiece surfaces

2020 ◽  
pp. 33-38
Author(s):  
L.V. Savelieva ◽  
A. A. Chudina
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Phase Transformations ◽  
High Temperatures ◽  
Plastic Deformations ◽  
Structural And Phase Transformations ◽  
Factors Influencing ◽  
Cutting Zone ◽  
The Moment

The basic data about residual stresses are considered, and the classification of residual stresses that occur in the surface layer of parts is provided. At the moment, it is customary to divide residual stresses by the volume of balancing into macro-stresses, micro-stresses and submicron stresses, and by the sign — compressive and tensile. The main causes of residual stresses are analyzed, and the factors influencing their occurrence are identified. There are three main causes of residual stresses: uneven plastic deformations in the cutting zone, as a result of the force of the tool on the workpiece, high temperatures accompanying the cutting process, and structural and phase transformations occurring on the surface of the workpiece.

Structural Phase Transformations of the Surface Layer of SiC Ceramics Irradiated by Intense Electron Beam

2016 ◽  
Vol 712 ◽  
pp. 81-86
Author(s):  
Yurii F. Ivanov ◽  
Oleg L. Khasanov ◽  
Maria S. Petyukevich ◽  
Valentina V. Polisadova ◽  
Tomara V. Milovanova ◽  
...  
Keyword(s):  
Surface Layer ◽  
Electron Beam ◽  
Phase Transformations ◽  
Structural Phase ◽  
Pulse Electron Beam ◽  
Experimental Investigations ◽  
Structural And Phase Transformations ◽  
Sic Ceramics ◽  
Intense Electron Beam ◽  
Intense Electron

Experimental investigations have been carried out to determine structural and phase transformations of a surface layer in SiC ceramics samples irradiated by an intense pulse electron beam of submillisecond duration. It was shown that electron beam modification of the surface layer of the SiC ceramics was followed by improvement of mechanical characteristics of the material. The suggestions have been made to explain this effect.

Structural and phase transformations in a carbide-strengthened alloy based on Ni3Al at high temperatures

1987 ◽  
Vol 30 (3) ◽  
pp. 228-231
Author(s):  
M. K. Kasymov ◽  
Yu. R. Kolobov ◽  
A. D. Korotaev ◽  
N. I. Afanas'ev ◽  
V. P. Buntushkin ◽  
...  
Keyword(s):  
Phase Transformations ◽  
High Temperatures ◽  
Structural And Phase Transformations

Improving management as a way to increase labour productivity

Upravlenie ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 24-30
Author(s):  
A. O. Ivanov
Keyword(s):  
Productivity Growth ◽  
Labour Productivity ◽  
Production Costs ◽  
Managerial Practices ◽  
Industrial Enterprises ◽  
Labour Productivity Growth ◽  
Period 2 ◽  
Main Factors ◽  
The Moment

The article gives an overview, performs analysis and classification of successful managerial practices applied at Russian industrial enterprises in the framework of the national project “Labour productivity and employment support”. The paper emphasizes the main factors of labour productivity growth as follows: investment policy, growth of human capital, and efficient use of managerial capital of enterprise. In order to determine the need of enterprises to increase labour productivity, the author proposes four universal criteria that signal the existing inefficiency even before the loss of competitiveness: 1) the dynamics of labour productivity in the company is not positive during a given period; 2) the company is behind competitors by labour productivity indicator; 3) the company is behind competitors by labour productivity growth rates indicator for a certain period; 4) unit production costs rise. These criteria allow you to take into account the situation both within the enterprise and in comparison with other enterprises. Each criteria can be considered separately or in combination with the others, applied to enterprises of different industries, specialization, and scale. Criteria indicate the direction of development in which the company is experiencing difficulties at the moment, or may experience them in the future.

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.

Small Bowel Obstruction

2010 ◽  
Vol 21 (2) ◽  
pp. 187-194
Author(s):  
Colleen Trevino
Keyword(s):  
Small Bowel ◽  
Physical Examination ◽  
Surgical Intervention ◽  
Signs And Symptoms ◽  
Bowel Ischemia ◽  
Key Factors ◽  
The Past ◽  
Factors Influencing ◽  
Imaging Response

Strategies for the management of small bowel obstructions have changed significantly over the years. Nonoperative medical management has become the mainstay of treatment of many small bowel obstructions. However, the key to the management of small bowel obstructions is identifying those patients who need surgical intervention. Identification of those at risk for bowel ischemia and bowel death is an art as much as it is a science. Using the current literature and the past knowledge regarding small bowel obstructions, the clinician must carefully identify the signs and symptoms that suggest the need for operative intervention. Classification of the obstruction, history and physical examination, imaging, response to decompression and resuscitation, and resolution or progression of symptoms are the key factors influencing the management of small bowel obstructions.

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.

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