Development of Parameters Describing Heterogeneous Hardened Structure

2015 ◽  
Vol 756 ◽  
pp. 75-78 ◽  
Author(s):  
A. Kirichek ◽  
S.V. Barinov

The technique was developed with the purpose of definition of parameters for surface layer uniformity after mechanical hardening. It was found that one of the most effective methods of surface plastic deformation that provide precise adjustment of uniformity level of surface layer hardening is presented by static-pulse treatment technique. This method helps to develop hardened surface layer 8 mm deep with virtually uniform or heterogeneous structure.

2020 ◽  
Vol 303 ◽  
pp. 89-96
Author(s):  
K.S. Mitrofanova

The results of experimental studies of the thin surface layer of samples made of steel 45 after treatment with surface plastic deformation (SPD) multiradius roller (MR-roller) are presented. On the basis of the apparatus of the mechanics of technological inheritance, taking into account the effect of the solidified body, a model of the process according to the scheme of multiple loading-unloading of metal, taking into account the phenomenology of the SPD process and the properties of the material, is created. Distributions of parameters of the stress-strain state in the deformation centre are obtained, the parameters of roughness and microhardness of the surface layer are investigated.


Author(s):  
А. Афонин ◽  
A. Afonin ◽  
Е. Мартынов ◽  
E. Martynov ◽  
А.В. Макаров ◽  
...  

The main causes of failure of heavily loaded threads are considered. The methods of increasing the efficiency of the equipment due to the method used are proposed. It is found that improving the operational characteristics of the components of mining and metallurgical machinery can be achieved forming heterogeneous-hardened surface layer. Methods of forming heterogeneous structure by surface plastic deformation (SPD are considered). The importance of identifying the nature of the influence of parameters of heterogeneous hardened layer on the performance of machine parts is indicated. Modeling of process heterogeneous hardening of SPD of the finite element method is executed. Recommendations about application of heterogeneous hardening of SPD for hardening the heavy-duty parts are offered. It is found that the use of different methods SPD allows widely vary the degree of depth and the uniformity of the hardening of machine parts. It is found that this increase in life responsible highly loaded parts operating under fatigue loading due to hardening of the heterogeneous surface layer may reach 1.5 times or more.


2021 ◽  
Vol 2021 (4) ◽  
pp. 3-9
Author(s):  
Roman Gurov ◽  
Andrey Shcherbakov

There are offered dependences for the definition of parameters formed for surface layer quality when finishing and finish-strengthening with surface-plastic deformation, for the definition of processing modes, tool geometrical parameters taking into account initial parameters of surface layer quality. Criteria for the choice of the processing method ensuring quality parameters required for a surface layer and surface operation properties are offered.


2015 ◽  
Vol 788 ◽  
pp. 3-10
Author(s):  
Valeriy Yu. Blumenstein ◽  
Fyodor I. Panteleenko ◽  
Igor V. Miroshin ◽  
Oleg A. Ostanin

Methods and experimental findings shown describe how mechanical parameters of the surface layer behavior and acoustic emission signals are interconnected.Experimental study was carried out under conditions of simple single-and dual stage compression. Graphic and analytic dependencies between the counting rate of the acoustic emission Ṅ and the shear deformation degree Λ were revealed. The findings describing dual compression show that the acoustic emission method is sensitive to the material stressing history.The dependency of the acoustic emission signal energy on the pre-stressing program was found, which helped establish that, with values of the plasticity reserve depletion being equal for all experimental specimens, the accumulated shear deformation degree Λ was different.The findings describing the hereditable physical state of the strengthened surface layer of parts during cutting and surface plastic deformation are presented in the paper. The study was carried out using the methods of property accumulation control in deformation sites depending on treatment modes with real-time monitoring of acoustic emission signals. A peculiar feature of these methods is the use of visual recording of the metal plastic flow to be further used in calculating the hereditable parameters of the surface layer quality.


2020 ◽  
Vol 63 (10) ◽  
pp. 802-807
Author(s):  
S. A. Zaides ◽  
. Pham Van Anh

Cold drawn calibrated steel is an effective blank for the manufacture of low-rigid cylindrical parts such as shafts and axles. High accuracy of the diametric size along the length of the workpiece, low surface roughness, increased hardness and strength of the surface layer compared to hot rolled products allow us to produce a variety of parts with high metal utilization and high machining performance. The main disadvantage of calibrated metal is the residual stresses that occur during pressure treatment. To reduce or change the nature of the distribution over the cross section, it is proposed to use small plastic deformations in the surface layer of the hire. Known in practice methods of surface plastic deformation (PPD) usually lead to the curvature of non-rigid workpieces. To intensify the stress-strain state in the deformation zone, we propose a method of orbital surface deformation. Based on the finite element modeling, influence of the main parameters of orbital surface deformation on stress state in the deformation zone and residual stresses in the finished products is considered. Compared with the traditional PPD process, the stress intensity during orbital surface deformation will increase by 10 – 15 %. The residual compressive stresses that form in the surface layers reach 70 – 85 % of the material tensile strength. In the second part of the article, it is supposed to provide information on a more effective method of surface deformation and on the change in initial residual stresses that are formed during the calibration of cylindrical rods.


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.


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