scholarly journals Recycling of stainless steel bar scrap by radial-shear rolling to obtain an ultrafine-grained gradient structure

2021 ◽  
pp. 61-67
Author(s):  
S. N. Lezhnev ◽  
A. B. Naizabekov ◽  
I. E. Volokitina ◽  
E. A. Panin ◽  
D. V. Kuis
Keyword(s):  
Stainless Steel ◽  
Cross Section ◽  
Rolling Mill ◽  
Axial Zone ◽  
Degree Of Deformation ◽  
Steel Bar ◽  
Ultrafine Grained ◽  
Different Types ◽  
Radial Shear Rolling ◽  
Stainless Austenitic Steel

This work is devoted to the study of the possibility of recycling bar scrap of stainless metals using radial-shear rolling. In the course of studies on the deformation of bar scrap in the form of pins made of 12X18N9T stainless austenitic steel on a radial-shear rolling mill, the resulting bar was obtained microstructure of two different types: on the periphery an equiaxed ultrafine-grained structure with a grain size of 0.4–0.6 microns was formed; in the axial zone anoriented, banded texture was obtained. This discrepancy in the structure of the peripheral and axial zones, together with the results of cross-section microhardness measurements of samples made of 12X18N9T austenitic stainless steel with a total degree of deformation of 44.4 %, indicates the gradient nature of the resulting microstructure.

Approach and Effect Analysis of Amplitude Frequency Performance Improvement in Metal Bar Cropping with Variable Frequency Vibration

2012 ◽  
Vol 152-154 ◽  
pp. 770-774
Author(s):  
Li Jun Zhang ◽  
Jie Qiong Xue ◽  
Sheng Dun Zhao ◽  
Yong Rui Zhao
Keyword(s):  
Performance Improvement ◽  
Cross Section ◽  
Narrow Range ◽  
Experimental Results ◽  
Variable Frequency ◽  
Structure Model ◽  
Effect Analysis ◽  
Steel Bar ◽  
Different Types ◽  
And Control

In order to solve the narrow range and control difficulties of the excited frequency in metal bar cropping with variable frequency vibration, the structure of the eccentric block in cropping machine was improved on in the paper and a new structure model of changing the integral eccentric block into one of main eccentric block and some small adjustable eccentric blocks, was also proposed. The key parameters of the cropping machine in the action of two different types of eccentric blocks were analyzed theoretically in detail. At the same time, the corresponding amplitude frequency characteristics of the cropping machine were also obtained. The cropping experimental results of 45 steel bar show that the cross-section quality and the cropping time are improved remarkably in the action of one main eccentric block and four adjustable eccentric blocks, comparing with the cropping results in the action of the whole eccentric block.

scholarly journals The effect of radial-shear rolling on microstructure and mechanical properties of stainless austenitic steel AISI-321

2018 ◽  
Vol 190 ◽  
pp. 11003 ◽  
Author(s):  
Abdrakhman Naizabekov ◽  
Sergey Lezhnev ◽  
Alexandr Arbuz ◽  
Evgeniy Panin
Keyword(s):  
Mechanical Properties ◽  
Austenitic Steel ◽  
Strength Properties ◽  
Grain Structure ◽  
Microstructure And Mechanical Properties ◽  
Ultrafine Grained ◽  
Steel Aisi ◽  
Aisi 321 ◽  
Radial Shear Rolling ◽  
Stainless Austenitic Steel

Improving the quality of metal products by crushing of the microstructure of material is one of the promising areas of modern metallurgy. The basic idea consists in refinement the grain structure of the material to sizes less than a micron, i.e. the obtaining of ultrafine-grained (UFG) materials, offering higher strength properties of the material under preservation or a small loss of ductility. Stainless austenitic steel AISI 321 is widely used in all the above areas as well as in chemical, vacuum and nuclear technology. For the obtaining of UFG structure in this material the method of radial-shear rolling is used. For the purpose of identifying the influence of radial-shear rolling on microstructure and mechanical properties of stainless austenitic steel AISI-321, the experiment was conducted where at the radial-shear rolling mill SVP-08 at 800 °C in several passes of the workpieces with a diameter of 30 mm rolled till a diameter of 13 mm with following cooling in water. The analysis of the microstructure of deformed samples showed the presence of equiaxed ultrafine-grained structure in the peripheral areas of the workpiece and the presence of elongated fibrous texture in the axial zone. The strength characteristics of the workpiece has increased more than 2 times, with a slight decrease of plasticity.

scholarly journals Statistical Research of Stainless Austenitic Steel Grain Size Distribution after Screw Rolling

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5048
Author(s):  
Mikhail Mikhailovich Skripalenko ◽  
Tatyana Viktorovna Zavyalova ◽  
Zbigniew Pater ◽  
Boris Alekseevich Romantsev ◽  
Stanislav Olegovich Rogachev ◽  
...  
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Cross Section ◽  
Screw Rolling ◽  
Statistical Research ◽  
Strong Negative Correlation ◽  
Billet Cross Section ◽  
Stainless Austenitic Steel

Screw rolling of austenitic stainless-steel billets was conducted in two- and three-high mills. Statistical research results showed that, compared to heated but not rolled conditions, both screw rolling techniques provided a decrease of grain size, variance, grain size distribution asymmetry, and excess in the billet cross-section at the stationary stage of screw rolling. At that stage, grain size distribution after two-high screw rolling is closer to normal in terms of asymmetry and excess values compared to grain-size distribution after three-high screw rolling. A strong negative correlation between strain effective values and grain-size values for the cross-section of the rolled billets at the stationary stage was revealed for both two- and three-high screw rolling.

scholarly journals Radial-shear rolling as a new technological solution for recycling bar scrap of ferrous metals

2021 ◽  
Vol 316 (1) ◽  
pp. 46-52
Author(s):  
S. N. Lezhnev ◽  
◽  
A. B. Naizabekov ◽  
I. E. Volokitina ◽  
E. A. Panin ◽  
...  
Keyword(s):  
Rolling Mill ◽  
New Technology ◽  
Waste Recycling ◽  
Steel Grade ◽  
Initial Value ◽  
Rolling Mills ◽  
Ferrous Metals ◽  
Ultrafine Grained ◽  
Radial Shear Rolling ◽  
Grade Steel

Waste recycling of both ferrous and non-ferrous metals is a useful process for the economy of any country. This paper proposes a new technology for recycling bar scrap of ferrous metals by rolling it in radial-shear rolling mills by producing a commercial product in the form of bars with an ultrafine-grained gradient structure. Studies have shown that the deformation of bar scrap in the form of pieces of reinforcement made of steel grade 18G2S in a radial-shear rolling mill makes it possible to significantly disperse its structure by producing a gradient ultrafine-grained structure, and this, in turn, leads to the elevating of the mechanical characteristics of this steel grade. Thus, the tensile limit of the 18G2S grade steel deformed on the radial-shear rolling mill was 620 MPa (at the initial value of 365 MPa).

First and Second Order Elastoplastic Analyses of Thin-Walled Metal Members using Generalized Beam Theory

2018 ◽  
Author(s):  
Miguel Abambres
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Cross Section ◽  
Beam Theory ◽  
Second Order ◽  
Flow Rule ◽  
Non Linear ◽  
Thin Walled ◽  
Shell Finite Element ◽  
Generalized Beam Theory

Original Generalized Beam Theory (GBT) formulations for elastoplastic first and second order (postbuckling) analyses of thin-walled members are proposed, based on the J2 theory with associated flow rule, and valid for (i) arbitrary residual stress and geometric imperfection distributions, (ii) non-linear isotropic materials (e.g., carbon/stainless steel), and (iii) arbitrary deformation patterns (e.g., global, local, distortional, shear). The cross-section analysis is based on the formulation by Silva (2013), but adopts five types of nodal degrees of freedom (d.o.f.) – one of them (warping rotation) is an innovation of present work and allows the use of cubic polynomials (instead of linear functions) to approximate the warping profiles in each sub-plate. The formulations are validated by presenting various illustrative examples involving beams and columns characterized by several cross-section types (open, closed, (un) branched), materials (bi-linear or non-linear – e.g., stainless steel) and boundary conditions. The GBT results (equilibrium paths, stress/displacement distributions and collapse mechanisms) are validated by comparison with those obtained from shell finite element analyses. It is observed that the results are globally very similar with only 9% and 21% (1st and 2nd order) of the d.o.f. numbers required by the shell finite element models. Moreover, the GBT unique modal nature is highlighted by means of modal participation diagrams and amplitude functions, as well as analyses based on different deformation mode sets, providing an in-depth insight on the member behavioural mechanics in both elastic and inelastic regimes.

scholarly journals Microstructural Investigation of a Friction-Welded 316L Stainless Steel with Ultrafine-Grained Structure Obtained by Hydrostatic Extrusion

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1537
Author(s):  
Beata Skowrońska ◽  
Tomasz Chmielewski ◽  
Mariusz Kulczyk ◽  
Jacek Skiba ◽  
Sylwia Przybysz
Keyword(s):  
Stainless Steel ◽  
Electron Microscope ◽  
Friction Welding ◽  
High Speed ◽  
316L Stainless Steel ◽  
Welded Joint ◽  
Microstructural Investigation ◽  
Ultrafine Grained Structure ◽  
Ultrafine Grained ◽  
Friction Joint

The paper presents the microstructural investigation of a friction-welded joint made of 316L stainless steel with an ultrafine-grained structure obtained by hydrostatic extrusion (HE). Such a plastically deformed material is characterized by a metastable state of energy equilibrium, increasing, among others, its sensitivity to high temperatures. This feature makes it difficult to weld ultra-fine-grained metals without losing their high mechanical properties. The use of high-speed friction welding and a friction time of <1 s reduced the scale of the weakening of the friction joint in relation to result obtained in conventional rotary friction welding. The study of changes in the microstructure of individual zones of the friction joint was carried out on an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and electron backscattered diffraction (EBSD) analysis system. The correlation between the microstructure and hardness of the friction joint is also presented. The heat released during the high-speed friction welding initiated the process of dynamic recrystallization (DRX) of single grains in the heat-affected zone (HAZ). The additional occurrence of strong plastic deformations (in HAZ) during flash formation and internal friction (in the friction weld and high-temperature HAZ) contributed to the formation of a highly deformed microstructure with numerous sub-grains. The zones with a microstructure other than the base material were characterized by lower hardness. Due to the complexity of the microstructure and its multifactorial impact on the properties of the friction-welded joint, strength should be the criterion for assessing the properties of the joint.

scholarly journals The Chosen Aspects of Skew Rolling of Hollow Stepped Shafts

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 764
Author(s):  
Jarosław Bartnicki ◽  
Yingxiang Xia ◽  
Xuedao Shu
Keyword(s):  
Cross Section ◽  
Rolling Mill ◽  
Metal Flow ◽  
Experimental Tests ◽  
Rolling Process ◽  
Numerical Control ◽  
Technological Parameters ◽  
Flow Mechanisms ◽  
The Individual ◽  
Skew Rolling

The paper presents chosen aspects of the skew rolling process of hollow stepped products with the use of a skew rolling mill designed and manufactured at the Lublin University of Technology. This machine is characterized by the numerical control of spacing between the working rolls and the sequence of the gripper axial movement, which allows for the individual programming of the obtained shapes of parts such as stepped axles and shafts. The length of these zones and the values of possibly realizable cross-section reduction and obtained outlines are the subject of this research paper. The chosen results regarding the influence of the technological parameters used on the course of the process are shown in the present study. Numerical modelling using the finite element method in Simufact Forming, as well as the results of experimental tests performed in a skew rolling mill, were applied in the conducted research. The work takes into account the influence of cross-section reduction of the hollow parts and the feed rate per rotation on the metal flow mechanisms in the skew rolling process. The presented results concern the obtained dimensional deviations and changes in the wall thickness determining the proper choice of technological parameters for hollow parts formed by the skew rolling method. Knowledge about the cause of the occurrence of these limitations is very important for the development of this technology and the choice of the process parameters.

Favorable Modulation of Pre-Osteoblast Response to Nanograined/Ultrafine-grained Structures in Austenitic Stainless Steel

2009 ◽  
Vol 21 (12) ◽  
pp. 1280-1285 ◽  
Author(s):  
R.D.K. Misra ◽  
W-W. Thein-Han ◽  
T.C. Pesacreta ◽  
K.H. Hasenstein ◽  
M.C. Somani ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Ultrafine Grained

The study of neutron capture processes in AlN nanoparticles

2021 ◽  
pp. 2150127
Author(s):  
T. G. Naghiyev
Keyword(s):  
Computer Modeling ◽  
Cross Section ◽  
Neutron Capture ◽  
Absorption Cross Section ◽  
Effective Cross Section ◽  
Absorption Cross ◽  
Effective Absorption ◽  
Different Types ◽  
N Isotopes

The neutron capture processes in the AlN nanoparticles were investigated by computer modeling. Neutrons absorption were separately investigated for aluminum (Al) and nitrogen (N) atoms in the AlN nanoparticles. The modeling was performed separately for each stable Al and N isotopes, because the effective absorption cross-section of different types of isotopes of Al and N atoms is different. Moreover, effective cross-section spectra of neutron capture for aluminum and nitrogen atoms were comparatively investigated.

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