Influence of Asymmetric Rolling Process and Thickness Reduction on the Microstructure and Mechanical Properties of the Al–Mg-Si Alloy

Author(s):  
Xuehong Xu ◽  
Yunlai Deng ◽  
Xiaobin Guo ◽  
Qinglin Pan
2005 ◽  
Vol 475-479 ◽  
pp. 529-532
Author(s):  
Tae Kwon Ha ◽  
Hwan Jin Sung ◽  
Woo Jin Park ◽  
Sang Ho Ahn

The effect of warm rolling under various conditions on the microstructure and mechanical property was investigated using an AZ31 Mg alloy sheet. Several processing parameters such as initial thickness, thickness reduction by a single pass rolling, rolling temperature, roll speed, and roll temperature were varied to elicit an optimum condition for the warm rolling process of AZ31 Mg alloy. Microstructure and mechanical properties were measured for specimens subjected to rolling experiments of various conditions. Warm rolling of 30% thickness reduction per pass was possible without any side-crack at temperatures as low as 200oC under the roll speed of 30 m/min. The initial microstructure before rolling was the mixed one consisting of partially recrystallized and cast structures. Grain refinement was found to occur actively during the warm rolling, producing a very fine grain size of 7 µm after 50% reduction in single pass rolling at 200oC. Yield strength of 204MPa, tensile strength of 330MPa and uniform elongation of 32% have been obtained in warm rolled sheets.


2015 ◽  
Vol 60 (4) ◽  
pp. 2821-2826 ◽  
Author(s):  
A. Wierzba ◽  
S. Mróz ◽  
P. Szota ◽  
A. Stefanik ◽  
R. Mola

The paper presents the results of the experimental study of the three-layer Al-Mg-Al sheets rolling process by the ARB method. The tests carried out were limited to single-pass symmetric and asymmetric rolling processes. An Al-Mg-Al package with an initial thickness of 4 mm (1-2-1 mm) was subjected to the process of rolling with a relative reduction of 50%. To activate the shear band in the strip being deformed, an asymmetry factor of av=2 was applied. From the test results, an increase in the tensile strength of the multi-layer Al-Mg-Al sheets obtained from the asymmetric process was observed. Microhardness tests did not show any significant differences in aluminium layer between respective layers of sheets obtained from the symmetric and the asymmetric process. By contrast, for the magnesium layer, an increase in microhardness from 72 HV to 79 HV could be observed for the asymmetric rolling. The analysis of the produced Al-Mg-Al sheets shows that the good bond between individual layers and grain refinement in the magnesium layer contributed to the obtaining of higher mechanical properties in the multi-layer sheets produced in the asymmetric process compared to the sheets obtained from the symmetric process.


2012 ◽  
Vol 581-582 ◽  
pp. 842-846
Author(s):  
Jian Hua Zeng ◽  
Yi Chang Li ◽  
Zheng Zhou ◽  
Jun Chen

Effect of the laying head temperature and controlled cooling process on microstructure and mechanical properties of 72LXA wire rod were investigated.The results show that under the same cooling process,with the raising laying temperature and increasing sorbitizing rate and decreasing proeutectoid ferrite,the steel rod strength is improving,proeutectoid ferrite and sorbitizing rate are the critical impact factors on steel rod properties;indentifying cooling after perlite forming can restrain the dissolve of lamellar cementite;the mechanical properties of whole rod coil are improved by the proper rolling rate and air cooling.The high strength of 1050 MPa of steel rod was obtained,that shows the defined hot rolling process can conform to the steel rod properties requirement.


2018 ◽  
Vol 918 ◽  
pp. 48-53 ◽  
Author(s):  
Olexandr Grydin ◽  
Mykhailo Stolbchenko ◽  
Maria Bauer ◽  
Mirko Schaper

The industrial application of high-alloyed Al-Mg-Si alloys for the production of thin strips by means of twin-roll casting is limited due to the structural inhomogeneity and segregation formation. To reach the highest mechanical properties of the finished product, a direct influence on the strip formation conditions during the twin-roll casting can be applied. Analogous to the asymmetric rolling process, additional shear stresses were created in the strip forming zone by using different circumferential velocities and torques of the caster rolls. To provide the asymmetric process conditions, only one caster roll was left driven and the second one was left idling during the casting process. The microstructure and the mechanical properties of the strips in the as-cast state as well as after the homogenization and subsequent age-hardening were analyzed. A comparison of the test results showed a positive influence of the asymmetry conditions on the strips’ properties.


Author(s):  
V.G. Razdobreev ◽  
D.G. Palamar

The aim of the work is to study the influence of the process of hot asymmetric rolling on the structural state, mechanical properties and operational characteristics of long products of simple form from ordinary carbon steel. To simulate the process of asymmetric high-quality rolling, the mathematical model previously developed in the ISI added the possibility of taking into account cases of rolling in a pair of rolls of different diameters, rolling in a pair of rolls of different materials, rolling with one drive and one non-drive rolls, rolling at different speeds in a pair of rolls and other. The calculations showed a reduction in rolling force to 10 % with an asymmetric rolling process compared to the traditional rolling process. The study of the features of the process of hot asymmetric rolling (shear rolling) compared with the traditional rolling process was carried out under industrial conditions in the production of a 12x12 mm square profile from ordinary low-carbon steel St3sp. It was found that the average values of HRB, σВ, and σТ in the studied samples practically do not differ, and the average values of δ5 are higher by 8 % (abs.) or ~ 27 % (rel.) In samples that were rolled using the asymmetric rolling technology than in samples that were rolled using traditional rolling technology. The estimation of dislocation density by the X-ray diffraction method showed that during hot asymmetric rolling, the dislocation density is reduced by ~ 46% due to the active flow of in-situ polygonization and recrystallization processes during deformation. In this case, the average values of the microfractures of the crystalline lattice of ferrite are 21% lower in the samples obtained by the method of asymmetric rolling than in the samples obtained by traditional rolling. For the first time, a decrease in the total atmospheric corrosion rate was found in samples that were rolled using asymmetric rolling technology (0.39 g/m2xh) compared to samples that were rolled using traditional rolling technology (0.445 g/m2xh).


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