Design and development of aluminum alloy 6061-T6 pressure vessel liner for aerospace applications: A technical brief

Author(s):  
R Pramod ◽  
N Siva Shanmugam ◽  
C K Krishnadasan ◽  
G Radhakrishnan ◽  
Manu Thomas

This work mainly focuses on designing a novel aluminum alloy 6061-T6 pressure vessel liner intended for use in launch vehicles. Fabrication of custom-made welding fixtures for the assembly of liner parts, namely two hemispherical domes and end boss, is illustrated. The parts of the liner are joined using the cold metal transfer welding process, and the welding trials are performed to arrive at an optimized parametric range. The metallurgical characterization of weld joint reveals the existence of dendritic structures (equiaxed and columnar). Microhardness of base and weld metal was 70 and 65 HV, respectively. The tensile strength of base and weld metal was 290 and 197 MPa, respectively, yielding a joint efficiency of 68%. Finite-element analysis of a uniaxial tensile test was performed to predict the tensile strength and location of the fracture in base and weld metal. The experimental and predicted tensile test results were found to be in good agreement.

2019 ◽  
Vol 813 ◽  
pp. 404-410
Author(s):  
Hardik Vyas ◽  
Kush P. Mehta

In the present investigation, friction stir processing (FSP) is carried out with multi pass processing having 100 % overlap zone on the workpiece material of aluminum alloy 6061 with constant FSP parameters and varying multi pass processing conditions. Novel processing concept of multi pass FSP was performed with different rotation directions (such as clock wise and anti-clock wise directions) and processing directions (such as forward, reverse and revert directions). Surface inspection, macrographs and microstructures of the processed regions are evaluated and compared with each other. Multi-pass FSP with 100 % overlapping of two passes caused intense dynamic recrystallization and resulted in reduced grain size. Hardness of processed zone was found increased in case of two pass FSP. Minimum tensile strength was reported with double sided FSP compare to single pass and two pass FSPs. No major variations in tensile strength were reported in case of single pass and two pass FSPs.


Author(s):  
Eun-chae Jeon ◽  
Joo-Seung Park ◽  
Doo-Sun Choi ◽  
Kug-Hwan Kim ◽  
Dongil Kwon

The instrumented indentation test, which measures indentation tensile properties, has attracted interest recently because this test can replace uniaxial tensile test. An international standard for instrumented indentation test has been recently legislated. However, the uncertainty of the indentation tensile properties has never been estimated. The indentation tensile properties cannot be obtained directly from experimental raw data as can the Brinell hardness, which makes estimation of the uncertainty difficult. The simplifying uncertainty estimation model for the indentation tensile properties proposed here overcomes this problem. Though the influence quantities are generally defined by experimental variances when estimating uncertainty, here they are obtained by calculation from indentation load-depth curves. This model was verified by round-robin test with several institutions. The average uncertainties were estimated as 18.9% and 9.8% for the indentation yield strength and indentation tensile strength, respectively. The values were independent of the materials’ mechanical properties but varied with environmental conditions such as experimental instruments and operators. The uncertainties for the indentation yield and tensile strengths were greater than those for the uniaxial tensile test. These larger uncertainties were caused by measuring local properties in the instrumented indentation test. The two tests had the same tendency to have smaller uncertainties for tensile strength than yield strength. These results suggest that the simplified model can be used to estimate the uncertainty in indentation tensile properties.


2015 ◽  
Vol 1129 ◽  
pp. 445-452
Author(s):  
Z. Kamil ◽  
G. Andrzej ◽  
C. Sandra ◽  
A.J. Barroso

In this research, five types of polymer repair materials were selected for investigation of the influence of sample shape, deformation rate and test temperature on the mechanical properties determined with an uniaxial tensile test. The results showed the clear effect of measurement conditions on tensile strength, elongation and modulus of elasticity. The highest tensile strength and modulus of elasticity were exhibited by epoxy resin for the filling of concrete cracks, which achieved 1% elongation. The lowest coefficient of dispersion characterized the results of tensile test carried out using dumbbell samples at a deformation rate of 50 mm/min. The effect of temperature varied with the material type.


2018 ◽  
Vol 5 (6) ◽  
pp. 14345-14354
Author(s):  
C. Ayyanar ◽  
M. Suresh ◽  
P.V. ArunRaj ◽  
M. Rajmadhan

2020 ◽  
Vol 12 (6) ◽  
pp. 892-898
Author(s):  
Gang Liu ◽  
Kai-Shu Guan ◽  
Ji-Ru Zhong

In order to research the method of strength empirical correlation between conventional small punch test (SPT) and uniaxial tensile test, a series of austenitic stainless steel including pre-strained SUS304 have been tested in this study. The conventional SPT is conducted on a small disc-shaped specimen whose edge is firmly gripped by a die, and the specimen is deformed by a punch. The method of empirical correlation between SPT and uniaxial tensile test is a direct way to obtain the mechanical properties of materials. Through establishing the strength empirical correlation, it can achieve to calculate the strength of material by SPT which is nondestructive to equipments. However, the per-strained steels have never been tested in this method. This study is to fill that gap and to obtain the empirical correlation between SPT and uniaxial tensile test with pre-strained steel. In this study, a series of austenitic stainless steel including SUS304 after different levels of pre-strain were tested successively by uniaxial tensile test and SPT. It is found that the tensile strength obtained from uniaxial tensile test increases with the increasing levels of pre-strain. However, the maximum load obtained from prestrained SPT specimen does not increase with the increasing levels of pre-strain. It is contradictory to the linear relation between maximum load and tensile strength. According to the analysis of conventional discshaped SPT specimen, the directions of maximum load obtained from SPT and tensile strength from tensile test are not uniform. It results in the non-linearity between the maximum load and the tensile strength with pre-strained steel, and it indicates the pre-strained steel cannot be applied to the conventional disc-shaped SPT specimen. Furthermore, the prestrained steel is a typical kind of anisotropic material. Therefore, extending to anisotropic material, the conventional disc-shaped SPT specimen is not suitable for the method of strength empirical correlation.


Author(s):  
Naotaka Nakamura ◽  
Ken-ichiro Mori ◽  
Hiroki Okada ◽  
Yohei Abe

AbstractA punching test for simply estimating the tensile strength and total elongation of steel sheets and formed parts was proposed. The tensile strength and total elongation were estimated from the shear stress at the maximum punching load and percentage of the burnished depth at the sheared edge of the slug measured without cutting, respectively. For a variety of steel sheets with a range of the tensile strength from 360 to 1500 MPa, linear functions for the estimation were experimentally obtained. The correlation of the estimated tensile strength of the steel sheets with the measured one from the uniaxial tensile test was considerably high, and the correlation of the estimated total elongation was high. The distributions of tensile strength and total elongation for hot- and cold-stamped parts were estimated. The proposed punching test is available under not only a laboratory environment but also a factory environment.


2020 ◽  
Vol 9 (1) ◽  
pp. 2100-2102

The surface temperature of hot die steel reaches typically up to 550ºC or above during processes like hot extrusion and casting non-ferrous material. The present paper explores the impact of austenitizing temperature as well as tempering temperature on the tensile strength of hot die steel. Heat treatment is done at three different austenitizing temperatures of 1010ºC, 1030ºC, and 1050ºC, followed by tempering done at two different temperatures of 540ºC and 580°C. Tempering is done twice for two hours. Metallographic grinding, polishing, and then etching using 2% Nital is done to investigate the microstructure of hot die steel with respect to its heat treatment. It is found that the grain size of hot die steel increases with an increase in austenitizing temperature. The impact on tensile strength of hot die steel for its heat treatment is examined by conducting the uniaxial tensile test to fracture. And investigation of the morphology of the fracture surface produced after the tensile test is done. It was found that hot die steel with large grain size exhibits lesser tensile strength. Whereas, the one having smaller grain has higher tensile strength that is found to be in accordance with the Hall-Patch equation


2004 ◽  
Vol 126 (4) ◽  
pp. 436-442
Author(s):  
J. J. Ahn ◽  
S. Ochiai

Mechanical properties of silicon carbide particle reinforced aluminum alloy 6061 composites with 5% and 10% SiCp/Al as well as aluminum alloy 6061 (AA6061) degraded by neutral 3.5% NaCl solution were examined by tensile tests and micro Vickers hardness measurement. The samples were degraded in the neutral 3.5% NaCl solution for a month ≑720h at 23°C (room temperature corrosion, RC) and 100°C (high temperature corrosion, HC). It is noted from surface observation of the corrosively degraded samples that the RC-samples (SiCp/Al and AA6061) were degraded by pitting around intermetallic compounds and SiC particles while corrosive degradation of the HC-samples was caused by synergy effect of pitting and intergranular corrosion. Corrosion reaction of the RC-samples was limited to their surface but the HC-samples were received severe corrosion damage until inside part. Thereby, mechanical strength of the latter (a maximum of 220 MPa) was lower than that of the former (a maximum of 330 MPa). Reduction of proof stress, σ0.2%, and ultimate tensile strength, σUTS, was greater in the SiCp/Al than in the AA6061 in the case of the same condition. The result to analyze the experimental data regressively showed that reduction of tensile strength for the RC-samples was proportional to the size of pit while tensile strength of the HC-samples was proportional to the ratio of corroded area to cross-section area. The empirical equations to evaluate the mechanical strength of both cases of the corrosively degraded samples (RC- and HC-samples) were proposed.


2020 ◽  
Vol 198 ◽  
pp. 02029
Author(s):  
Chang-yi Yu ◽  
Ming-yue Lu

Tensile strength of frozen soil is an important index for frozen soil engineering design. It is found that uniaxial tensile strength, three-point bending and four-point bending tensile strength values of frozen soil are inconsistent in the test. For this reason, the meso-level numerical method is adopted, assuming that the meso-level material parameters conform to Weibull distribution, and the damage model is adopted, and the macro-level material properties conform to linear elasticity assumption. Uniaxial tensile test, three-point bending tensile test and four-point bending tensile test are respectively simulated. The results show that the difference comes from the non-uniformity of materials. The results of this paper provide effective guidance for frozen soil strength design.


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