Influence of the Deformation Method on the Microstructure Changes in AZ31 Magnesium Alloy Round Rods Obtained by the Rolling Process

2016 ◽  
Vol 716 ◽  
pp. 864-870
Author(s):  
Andrzej Stefanik ◽  
Piotr Szota ◽  
Sebastian Mróz ◽  
Teresa Bajor ◽  
Sonia Boczkal
Keyword(s):  
Magnesium Alloy ◽  
Numerical Modelling ◽  
Rolling Mill ◽  
Laboratory Tests ◽  
Effective Strain ◽  
Rolling Process ◽  
Az31 Magnesium Alloy ◽  
Deformation Method ◽  
Microstructure Changes ◽  
Skew Rolling

This paper presents the research results of the microstructure changes of the round rods of AZ31 magnesium alloy in the hot rolling processes. The rolling was conducted in duo mill and a three-high skew rolling mill. Numerical modelling of the AZ31 magnesium alloy round rods rolling process was conducted using a computer program Forge 2011®. The verification of the results of numerical modelling was carried out during laboratory tests in a two-high rolling mill D150 and a three-high skew rolling mill RSP 40/14. Distributions of the total effective strain and temperature during AZ31 rods rolling process were determined on the basis of the theoretical analysis. Microstructure and texture changes during both analysed processes were studied.

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.

scholarly journals INFLUENCE OF A PREFABRICATED-CROWN ROLLING PROCESS ON THE CORROSION BEHAVIOUR OF AZ31 MAGNESIUM ALLOY

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Zhiquan Huang ◽  
Jinchao Zou ◽  
Junpeng Wang ◽  
Yanjie Pei ◽  
Renyao Huang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Plate Thickness ◽  
Az31 Alloy ◽  
Rolling Process ◽  
Charge Transfer Resistance ◽  
Az31 Magnesium Alloy ◽  
Transfer Resistance

The present study aims to investigate the effect of a prefabricated-crown rolling process on the corrosion characteristic of the AZ31 magnesium alloy. Specimens made of the AZ31 alloy were rolled under various crown conditions, and their microstructure evolution and corrosion behavior were analyzed. The corrosion behavior was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion-current density of the AZ31 alloy with a side pressure of 37.5 % of the plate thickness of the precast convexity decreased from 3.79 × 10–6 A/cm2 to 1.80 × 10–6 A/cm2, and the difference between the edge and the middle of the AZ31 alloy was shortened from 2.05 × 10–6 A/cm2 to 1.14 × 10–6 A/cm2. The charge-transfer resistance also increased from 507.1 Ω·cm2 to 581.2 Ω·cm2. The improvement in the corrosion resistance is a result of the more stable corrosion products and microstructure refinement formed after the prefabricated-crown rolling process.

scholarly journals Recrystallization Microstructure Prediction of a Hot-Rolled AZ31 Magnesium Alloy Sheet by Using the Cellular Automata Method

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Ming Chen ◽  
Xiaodong Hu ◽  
Hongyang Zhao ◽  
Dongying Ju
Keyword(s):  
Flow Stress ◽  
Magnesium Alloy ◽  
Cellular Automata ◽  
Process Analysis ◽  
Rolling Process ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Rolled Sheet ◽  
Element Analysis ◽  
Hot Rolled

A large reduction rolling process was used to obtain complete dynamic recrystallization (DRX) microstructures with fine recrystallization grains. Based on the hyperbolic sinusoidal equation that included an Arrhenius term, a constitutive model of flow stress was established for the unidirectional solidification sheet of AZ31 magnesium alloy. Furthermore, discretized by the cellular automata (CA) method, a real-time nucleation equation coupled flow stress was developed for the numerical simulation of the microstructural evolution during DRX. The stress and strain results of finite element analysis were inducted to CA simulation to bridge the macroscopic rolling process analysis with the microscopic DRX activities. Considering that the nucleation of recrystallization may occur at the grain and R-grain boundary, the DRX processes under different deformation conditions were simulated. The evolution of microstructure, percentages of DRX, and sizes of recrystallization grains were discussed in detail. Results of DRX simulation were compared with those from electron backscatter diffraction analysis, and the simulated microstructure was in good agreement with the actual pattern obtained using experiment analysis. The simulation technique provides a flexible way for predicting the morphological variations of DRX microstructure accompanied with plastic deformation on a hot-rolled sheet.

scholarly journals Properties of the AZ31 Magnesium Alloy Round Bars Obtained in Different Rolling Processes / Własności Prętów Okrągłych Ze Stopu Magnezu AZ31 Otrzymanych W Różnych Procesach Walcowania

2015 ◽  
Vol 60 (4) ◽  
pp. 3001-3006 ◽  
Author(s):  
A. Stefanik ◽  
P. Szota ◽  
S. Mróz ◽  
T. Bajor ◽  
H. Dyja
Keyword(s):  
Magnesium Alloy ◽  
Rolling Mill ◽  
Energy Demand ◽  
Experimental Studies ◽  
Tensile Tests ◽  
Modern Method ◽  
Extrusion Process ◽  
Mg Alloy ◽  
Static Tensile ◽  
Skew Rolling

Currently magnesium alloy bars are manufactured mainly in the extrusion process. This method has some drawbacks, which include: low process capacity, considerable energy demand, small length of finished products. Therefore it is purposeful to develop efficient methods for manufacturing of Mg alloy products in the form of bars, such methods include groove rolling and three-high skew rolling processes. Modified stretching passes provide change in material plastic flow, which contributes to the occurrence of the better distribution of stress and strain state than in the case of rolling in classical stretching passes. One of the modern method of Mg alloy bars production is rolling in a three-high skew rolling mill, which allows to set in a single pass a larger deformation compared to the rolling in the stretching passes. The paper presents the results of experimental studies of the AZ31 round bars production in the modified stretching passes and in the three-high skew rolling mill. The study of microstructural changes, hardness and the static tensile tests were made for as-cast and ready-rolled bars in both analyzed technologies.

Study on Heading and Thread-Rolling Processes of Magnesium Alloy Screws

2013 ◽  
Vol 535-536 ◽  
pp. 322-325 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Kai Neng Hwang ◽  
Chia Yu Chang
Keyword(s):  
Finite Element ◽  
Magnesium Alloy ◽  
Flow Pattern ◽  
Effective Strain ◽  
Metal Flow ◽  
Rolling Process ◽  
Die Set ◽  
Thread Rolling ◽  
Experimental Values ◽  
Two Stages

This study is to investigate the effects of the process parameters on the heading load and metal flow pattern during heading and thread-rolling processes of LZ91 magnesium alloy screws. A heading process composed of two stages is proposed. The material flow pattern of the billet inside the die is analyzed using the finite element analyses. The effects of the upper die velocity, temperatures and friction factors on the heading loads and product quality are discussed. On the other hand, in the thread-rolling process, the effects of the friction factor on the effective stress, effective strain, and tooth height are investigated. Finally, heading and thread-rolling experiments are conducted using a self-designed die set and a lubricant of MoS2. The experimental values are compared with the simulation results to verify the validity of the finite element models and the proposed heading procedures.

scholarly journals Numerical Analysis of a Skew Rolling Process for Producing a Stepped Hollow Shaft Made of Titanium Alloy Ti6Al4V

2016 ◽  
Vol 61 (2) ◽  
pp. 677-682 ◽  
Author(s):  
Z. Pater ◽  
T. Bulzak ◽  
J. Tomczak
Keyword(s):  
Numerical Analysis ◽  
Thickness Distribution ◽  
Effective Strain ◽  
Rolling Process ◽  
Forming Process ◽  
Hollow Shaft ◽  
Wall Thickness Distribution ◽  
Light Trucks ◽  
Titanium Alloy Ti6al4v ◽  
Skew Rolling

Abstract The paper describes a rolling process for a hollow Ti6Al4V alloy shaft used in driving systems of light trucks. The shaft is formed by skew rolling using three tapered rolls. The principle of this forming process was discussed stressing its universality due to the potential of applying it for forming various products by one set of rolls. The numerical analysis results (product shape progression in rolling, wall thickness distribution, effective strain, temperature and variations in loads and torques) confirm that the proposed technique can be used for producing hollow long shafts.

scholarly journals Critical Rolling Process Parameters for Dynamic Recrystallization Behavior of AZ31 Magnesium Alloy Sheets

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2019
Author(s):  
Wenke Wang ◽  
Qing Miao ◽  
Xuemin Chen ◽  
Yang Yu ◽  
Wencong Zhang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Dynamic Recrystallization ◽  
Process Parameters ◽  
Rolling Direction ◽  
Rolling Process ◽  
Alloy Sheet ◽  
Rolling Temperature ◽  
Az31 Magnesium Alloy ◽  
Texture Intensity ◽  
C 30

In this work, the influence of various rolling temperatures and thickness reductions on the dynamic recrystallization (DRX) behavior of AZ31 magnesium alloy sheets was investigated. Meanwhile, the texture variation controlled by DRX behavior was analyzed. Results suggested that, with the help of DRX behavior, reasonable matching of rolling temperature and thickness reduction could effectively refine the grain size and improve the microstructure homogeneity. Using the grain refinement and microstructure homogeneity as the reference, the critical rolling process parameters were 400 °C—30%, 300 °C—30%, and 250 °C—40% in the present work. In terms of basal texture variation, the occurrence of twins produced the largest maximum texture intensity. However, for the sheets with DRX behavior, the maximum texture intensity decreased sharply, but would steadily increase with the growth of DRXed grain. Additionally, for DRXed grains, the <11-20>//RD (RD: rolling direction) grains would gradually annex the <10-10>//RD grains with the growth of DRXed grains, which finally made their texture component become the dominant texture state. However, when the deformation continued, the <10-10> in DRXed grains would rotate toward the RD again. Weighted by the fracture elongation of AZ31 magnesium alloy sheet, the critical thickness reductions were 30–40% under the rolling temperature of 400 °C.

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