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

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]

2021 ◽  
Vol 244 ◽  
pp. 04001
Author(s):  
Georgi Kravchenko ◽  
Konstantin Kravchenko ◽  
Andrey Smolyaninov ◽  
Irina Kudryavtseva

Experimentally investigated patterns of changes in technological residual stresses under the influence of variable pressure in the surface layer became 30XNS2A. A mathematical model of relaxation of residual compressive stresses created by surface plastic deformation techniques with symmetrical cyclical bending of samples has been proposed. An empirical expression is proposed for assessing the final value of residual stresses as a result of cyclic loading, depending on the stress amplitude of a symmetric cycle. An expression is given for estimating the coefficient of relaxation rate of residual compressive stresses from their initial value, amplitude of alternating stresses and material properties. The constants of these expressions are determined for various construction materials. The theoretical dependences describe well the obtained experimental data. To predict the level of residual stress realization under operational loading, a formula was obtained to calculate their change as a result of the action of a step loading block with different amplitudes and duration of their action at each of the stages.


1973 ◽  
Vol 5 (5) ◽  
pp. 600-605
Author(s):  
V. S. Sysoeva ◽  
G. A. Chumak

2018 ◽  
Vol 919 ◽  
pp. 345-353 ◽  
Author(s):  
Marian Králik ◽  
Vladimír Jerz

This paper deals with the problem of stresses in the surface layer of materials after machining. It analyzes residual stresses as one of the factors affecting the state of the surface layer after machining. It describes the methods for measuring residual stresses and evaluates them from the point of view of suitability for industrial practice. A new method of measuring residual stresses in the surface layer of a workpiece for laboratory use has been proposed and experimentally tested. At the end of the article the options for further solutions in this area are proposed.


Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.


2021 ◽  
Vol 5 (2) ◽  
pp. 55
Author(s):  
Robert Zmich ◽  
Daniel Meyer

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.


2021 ◽  
Vol 65 (4) ◽  
pp. 643-651
Author(s):  
Th. Nitschke-Pagel ◽  
J. Hensel

AbstractThe consideration of residual stresses in fatigue-loaded welds is currently done only qualitatively without reliable knowledge about their real distribution, amount and prefix. Therefore, the tools which enable a more or less unsafe consideration in design concepts are mainly based on unsafe experiences and doubtful assumptions. Since the use of explicitly determined residual stresses outside the welding community is state of the art, the target of the presented paper is to show a practicable way for an enhanced consideration of residual stresses in the current design tools. This is not only limited on residual stresses induced by welding, but also on post-weld treatment processes like HFMI or shot peening. Results of extended experiments with longitudinal fillet welds and butt welds of low and high strength steels evidently show that an improved use of residual stresses in fatigue strength approximation enables a better evaluation of peening processes as well as of material adjusted welding procedures or post-weld stress relief treatments. The concept shows that it is generally possible to overcome the existing extremely conservative but although unsafe rules and regulations and may also enable the improved use of high strength steels.


2006 ◽  
Vol 524-525 ◽  
pp. 587-592 ◽  
Author(s):  
Wei Li ◽  
Michael Preuss ◽  
Philip J. Withers ◽  
Dragos Axinte ◽  
Paul Andrews

Holzforschung ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 67-72 ◽  
Author(s):  
J. van Houts ◽  
D. Bhattacharyya ◽  
K. Jayaraman

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.


2012 ◽  
Vol 430-432 ◽  
pp. 881-885
Author(s):  
Cai Jun Gan ◽  
Kai Liao

The level and distribution of residual stresses have great impact on dimensional stability, while Vibratory Stress Relief (VSR) is an effective technology to relax or homogenize residual stresses. Experimental study on residual stresses distribution, residual strain energy and machining deformation of 7075 high-strength aluminum alloy thick plate under different aging process status shows that VSR can effectively decrease the amplitude and strain energy density, and enhance stability of dislocation structures and phase states in metal microscopic volume, then internal residual stresses are homogenized to enhance components’ anti-deformation capacity. In addition, the capability in maintaining dimensional stability from VSR is better than that from traditional mechanical stretching process


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