scholarly journals Research on AZ80 + 0.4%Ce (wt %) Ultra-Thin-Walled Tubes of Magnesium Alloys: The Forming Process, Microstructure Evolution and Mechanical Properties

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 563 ◽  
Author(s):  
Zhaoming Yan ◽  
Min Fang ◽  
Zhendong Lian ◽  
Zhimin Zhang ◽  
Jiaxuan Zhu ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Wall Thickness ◽  
Vickers Hardness ◽  
Hardness Test ◽  
Optical Microscope ◽  
Forming Process ◽  
Average Grain Size ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Variable Wall

Ultra-thin-walled tubes of magnesium alloys have received more and more attention in producing precision components for medical devices. Therefore, thin-walled tubes with high quality are desperately needed. In this study, the process of multi-pass variable wall thickness extrusion was carried out on an AZ80 + 0.4%Ce Mg alloy with up to five passes—one-pass backward extrusion and four-pass extension—to fabricate the seamless thin-walled tube with an inside diameter of 6.0 mm and a wall thickness of 0.6 mm. The average grain size decreased from 46.3 μm to 8.9 μm at the appropriate deformation temperature of 350 °C with the punch speed of 0.1 mm/s. X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy (SEM), and the Vickers hardness (HV) tester were utilized to study the phases, microstructure, and hardness evolution. It can be observed that low deformation temperatures (240 °C and 270 °C) and low strain (1 pass extrusion and 1 pass extension) lead to twins that occupy the grains to coordinate deformation, and a slip system was activated with the accumulation of strain. The results of the Vickers hardness test showed that twinning, precipitation of second phases, twinning dynamic recrystallization (TDRX), and work hardening were combined to change the hardness of tubes at 240 °C and 270 °C. The hardness reached 93 HV after the third pass extension without annealing at 350 °C.

Microstructure and Texture Evolution of 0.6 mm Ultra-Thin-Walled Tubes of Magnesium Alloys Fabricated by Multi-Pass Variable Wall Thickness Extrusion (VWTE)

2020 ◽  
Vol 993 ◽  
pp. 427-433
Author(s):  
Zhao Ming Yan ◽  
Zhen Dong Lian ◽  
Min Fang ◽  
Zhi Min Zhang ◽  
Jia Xuan Zhu ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Texture Evolution ◽  
Extrusion Direction ◽  
Area Reduction ◽  
Average Grain Size ◽  
Coarse Grains ◽  
Thin Walled Tube ◽  
Variable Wall Thickness ◽  
Thin Walled ◽  
Variable Wall

AZ80+0.4%Ce alloy ultra-thin-walled tube with a wall thickness of 0.6 mm was fabricated by multi-pass variable wall thickness extrusion (VWTE) at 693 K. Microsturcture and texture evolution were investigated. The results indicate that the average grain size decreases from ~47 μm of extruded alloy to ~8.9 μm after 5 passes VWTE. The total area reduction of Mg alloy tube is 91 %. Homogeneity of microstructure is improved obviously and the morphology of Mg17Al12 phases in coarse grains and fine DRXed grains exhibit lamellar and granular shapes, respectively. In addition to the microstructure evolution, the VWTEed tubes showed a strong texture of (0001) planes, and the intensity decreased with deformation increasing to 4 passes. After 5p-VWTE, a strong texture characterized by (0001) pole tilting 20 degrees rotated from extrusion direction (ED) towards normal direction (ND).

scholarly journals Cold Forging Effect on the Microstructure of Motorbike Shock Absorbers Fabricated by Tube Forming in a Closed Die

2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui
Keyword(s):  
Material Flow ◽  
Cold Forging ◽  
Technological Parameters ◽  
Forming Process ◽  
Tube Forming ◽  
Shock Absorbers ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Quality Of Products ◽  
Forming Defects

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.

scholarly journals Evidence for Stacking Faults in Multiaxial Strained Alpha-Brass

1983 ◽  
Vol 27 ◽  
pp. 363-368
Author(s):  
R. B. Roof
Keyword(s):  
Wall Thickness ◽  
External Surface ◽  
Large Strain ◽  
Stacking Faults ◽  
Multiaxial Loading ◽  
Tube Surface ◽  
Line Broadening ◽  
X Ray ◽  
Thin Walled Tube ◽  
Thin Walled

As part of a program studying the effects of large strain deformations resulting from multiaxial loading to a variety of materials, a thin walled tube (0.46” O.D. x 0.02” wall thickness) of 70-30 Brass was subjected to strain deformation in the following directions 1) along the tube axis, εz = 0.3393; 2) circumferential around the tube surface, εθ = -0.0121; 3) perpendicular to the wall thickness, εR = 0.3514. This report describes the results of an x-ray examination of the external surface of the tube by the line broadening technique.

MINIMUM WALL THICKNESS OF HOLLOW THREADED PARTS IN THREE-DIE COLD THREAD ROLLING

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6112-6117 ◽  
Author(s):  
HUIPING QI ◽  
YONGTANG LI ◽  
JIANHUA FU ◽  
ZHIQI LIU
Keyword(s):  
Wall Thickness ◽  
High Efficiency ◽  
Low Cost ◽  
Work Piece ◽  
Forming Process ◽  
Minimum Thickness ◽  
Thread Rolling ◽  
Thin Walled ◽  
Rolling Technology ◽  
Good Agreement

The cold thread rolling technology was developed rapidly in recent years due to its high efficiency, low cost and perfect mechanical properties of its production. However, researches on the precise thread rolling of the hollow parts were very few. Traditionally, the minimum thickness of the thin-walled threaded parts by thread rolling was mainly determined by the empirical (trial and error) methods. In this study, the forming process of thin-walled thread parts rolled with three thread rolling dies was analyzed. The stress state of the hollow work piece was obtained by solving the statically indeterminate problems. Then, the equations for the minimum wall thickness were derived. Experiments are also performed. The experimental results are generally in good agreement with those by the current theoretical analysis. It could be concluded that the analysis presented in this study can provide a good guidance for the thread rolling of hollow parts.

An Approach for Analysis of Bulged Profile and Thickness Distribution of Tube in Free Hydro-Bulging Process

2012 ◽  
Vol 499 ◽  
pp. 127-131
Author(s):  
Xiao Feng Liu ◽  
Lian Fa Yang ◽  
Yu Xian Zhang
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Finite Element ◽  
Wall Thickness ◽  
Deformation Behavior ◽  
Thickness Distribution ◽  
Plastic Deformation Behavior ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Tubular Components

Tubular components are widely used in the areas of automotive and aerospace industries due to their excellent properties. A mathematical model considering the bulged region as a parabola curve is proposed to examine the plastic deformation behavior of a thin-walled tube during the free hydro-bulged process. The finite element simulations of the free hydro-bulging process are carried out to verify the approach indirectly. The results indicate that the model is accurate and acceptable to figure out the circumferential radius, wall thickness and axial radius of the bulged profile.

Process Parameter Analysis of Higher D/T Ratio Tube Formed From Sheet Hydroforming

2017 ◽  
Author(s):  
Duanyang Tian ◽  
Xuedao Shu ◽  
Yilun Wei ◽  
Yu Wang
Keyword(s):  
Wall Thickness ◽  
Large Diameter ◽  
Hydraulic Pressure ◽  
Blank Holder Force ◽  
Blank Holder ◽  
Forming Quality ◽  
Sheet Hydroforming ◽  
Thickness Uniformity ◽  
Thin Walled Tube ◽  
Thin Walled

As a core part of the aero engine casing, the thin-walled tube with large diameter usually formed by sheet hydroforming presents high forming precision and forming quality. In this paper, the appropriate hydraulic pressure and blank holder force should be identified to control the wall thickness uniformity of N08811 alloy tube with large diameter. Firstly, the stress-strain curve of this material at room temperature is obtained from deep drawing tests. Subsequently, within the allowable range of springback and wrinkling errors, finite element simulation and the uniform test design are performed to investigate the effect of the multi-level process parameters on the thickness uniformity of the higher D/t ratio tube. Results show that the blank holder force and the hydraulic pressure produce significant effects on the wall thickness uniformity. Finally, the regression analysis is further carried out for the computational results from uniform experimental design experiments. The optimized process parameters are then obtained and the wall thickness uniformity of the tube is improved. These results provide a theoretical reference for improving the forming quality of thin-walled tube with large diameter.

Theoretical, Numerical and Experimental Investigation of the Effects of Manufacturing Process Parameters on Thin-Walled Tube Bending Defects

2009 ◽  
Vol 83-86 ◽  
pp. 1107-1112
Author(s):  
J. Taheri Kahnamouei ◽  
Mohammad Sedighi
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Thickness Ratio ◽  
Outer Diameter ◽  
Tube Bending ◽  
Effective Parameters ◽  
Bending Process ◽  
Thin Walled Tube ◽  
Bending Radius ◽  
Thin Walled

The aim of this paper is to survey thin-walled tube bending process (without use of mandrel and booster). In tube bending process there are several effective parameters such as wall thickness, outer diameter-to-wall thickness ratio, and centerline bending radius-to-outer diameter ratio. Any mismatch in selecting these parameters would cause defects like wrinkling, variation in wall thickness, and cross section distortion. Firstly, the effects of these parameters on the initiation of the wrinkle, depth of wrinkling, change in wall thickness, and cross section distortion are studied. For this purpose, an FE commercial code has been used to simulate the process. Then, a series of experimental tests have been carried out to verify the results simulation. A comparison between analytical and experimental results shows a reasonable agreement with each other. Based on this comparison, it has been observed that there is a critical bending radius for any tube with a certain radius and thickness, in which the wrinkling begins to occur. For a certain bending angle and radius, it have been observed that the depth of wrinkling, change in wall thickness, and cross section distortion increase with reduction in wall thickness and outer diameter-to-wall thickness ratio

Microstructure and corrosion properties of SiC/Al-Mg-Cu-Si-Sn composites

2017 ◽  
Vol 24 (5) ◽  
pp. 709-713
Author(s):  
Rujuan Shen ◽  
Pengfei Zhou ◽  
Daihong Xiao ◽  
Min Song
Keyword(s):  
Vickers Hardness ◽  
Volume Fraction ◽  
Hardness Test ◽  
Optical Microscope ◽  
Corrosion Properties ◽  
Sic Particles ◽  
Peak Aged ◽  
Aged State ◽  
Time Required ◽  
Hot Pressing Sintering

AbstractThe SiC/Al-Mg-Cu-Si-Sn composites with different quantities of SiC particles by volume were fabricated using hot-pressing sintering. The effects of SiC volume fraction on the microstructure, Vickers hardness, and corrosion behavior of the composites were studied using the optical microscope, scanning electron microscope, Vickers hardness test, and corrosion testing. The results show that adding SiC particles shortened the time required to reach the peak-aged state of the composites and increased the hardness. Corrosion potentials of the composites did not vary greatly or show any definite trends in relation to the amounts of the SiC contents.

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