Study on the Residual Stress of LY12 Welded Component

2012 ◽  
Vol 602-604 ◽  
pp. 2114-2117
Author(s):  
Feng Xia ◽  
Jian Ping Li ◽  
Gao Hong Li ◽  
Man Zhu

In this paper, the distribution law of residual stress normal to the welding joint in LY12 aluminum alloy was measured by the combination use of hole drilling and electrical-measurement method. The experimental results indicated that it was an effective way to measure the residual stress of LY12 aluminum alloy with thickness of 6 mm by applying hole drilling. The distribution of residual stress vertical to welding joint is quite obvious. The residual stress increases as the distance away from the welding joint decreases. The value of the longitudinal residual stress is higher than that of the transverse residual stress. But they are all smaller than the value of ultimate stress in LY12 aluminum alloy. The heat treatment after welding can greatly improve the tensile strength of the weldment.

Author(s):  
J. S. Robinson ◽  
D. A. Tanner

Aerospace aluminum alloy forgings can have the residual stresses arising from heat treatment reduced by modification to the quench cooling rates and subsequent aging treatments. A series of propeller hubs usually made from the alloy 2014 have been closed die forged from the less quench sensitive alloy 7050. These forgings have been subjected to various quenching and aging treatments in an attempt to improve the balance of mechanical properties with the residual stress magnitudes. These forgings were not amenable to stress relieving by cold compression or stretching. Warm water (60°C) and boiling water quenches are investigated in addition to quenching into molten salt (200°C) and uphill quenching from −196°C. Various dual aging treatments including retrogression and reaging have been evaluated in an attempt to optimize low residual stress magnitudes with mechanical properties. Residual stresses determined by the center hole-drilling strain-gauge method are reported in addition to electrical conductivity, stress corrosion cracking, fracture toughness, initiation fatigue, and tensile mechanical property variations. It was found that quenching into boiling water and salt at 200°C did substantially reduce the residual stress but had only a small detrimental effect on the majority of the properties measured. However, the influence of quench rate on fracture toughness was much more significant. This is attributed to both coarse grain boundary precipitation and heterogeneous precipitation of η on Al3Zr dispersoids within the grains, which promotes easier crack propagation.


2013 ◽  
Vol 437 ◽  
pp. 555-559
Author(s):  
Yue Wang ◽  
Cai Hong Xue

A method of hole-drilling to estimate residual stress of welding joint of 2219-T87 aluminum alloy is proposed based on numerical simulation and measurement test. The influence of drilling-hole diameter to welding residual stress is first analyzed by numerical simulation, and the optimal diameter is obtained as 4.0 mm. In accordance with the diameter, carry out a test on measuring welding residual stress. And the maximum residual stress is calculated as 123.2 MPa.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4157 ◽  
Author(s):  
Isidro Guzmán ◽  
Everardo Granda ◽  
Jorge Acevedo ◽  
Antonia Martínez ◽  
Yuliana Dávila ◽  
...  

Precipitation hardening aluminum alloys are used in many industries due to their excellent mechanical properties, including good weldability. During a welding process, the tensile strength of the joint is critical to appropriately exploit the original properties of the material. The welding processes are still under study, and gas metal arc welding (GMAW) in pulsed metal-transfer configuration is one of the best choices to join these alloys. In this study, the welding of 6061 aluminum alloy by pulsed GMAW was performed under two heat treatment conditions and by using two filler metals, namely: ER 4043 (AlSi5) and ER 4553 (AlMg5Cr). A solubilization heat treatment T4 was used to dissolve the precipitates of β”- phase into the aluminum matrix from the original T6 heat treatment, leading in the formation of β-phase precipitates instead, which contributes to higher mechanical resistance. As a result, the T4 heat treatment improves the quality of the weld joint and increases the tensile strength in comparison to the T6 condition. The filler metal also plays an important role, and our results indicate that the use of ER 4043 produces stronger joints than ER 4553, but only under specific processing conditions, which include a moderate heat net flux. The latter is explained because Mg, Si and Cu are reported as precursors of the production of β”- phase due to heat input from the welding process and the redistribution of both: β” and β precipitates, causes a ductile intergranular fracture near the heat affected zone of the weld joint.


Author(s):  
Gary S. Schajer ◽  
Michael Steinzig

A novel dual-axis ESPI hole-drilling residual stress measurement method is presented. The method enables the evaluation of all the in-plane normal stress components with similar response to measurement errors, significantly lower than with single-axis measurements. A numerical method is described that takes advantage of, and compactly handles, the additional optical data that are available from the second measurement axis. Experimental tests were conducted on a calibrated specimen to demonstrate the proposed method, and the results supported theoretical expectations.


2014 ◽  
Vol 680 ◽  
pp. 11-14
Author(s):  
Ke Ren Shi ◽  
Sirikul Wisutmethangoon ◽  
Jessada Wannasin ◽  
Thawatchai Plookphol

In this study, semi-solid Al-Mg-Si alloy (AC4C) was produced by using the Gas Induced Semi-Solid (GISS) die casting process. The tensile strength and ductility of the semi-solid die cast Al alloy (GISS-DC) after T6 heat treatment were investigated and compared with those of the conventional liquid die casting (CLDC). The microstructures of GISS-DC and CLDC observed by an optical microscopy were presented. The ultimate tensile strength (UTS) and yield strength (0.2% YS) of GISS-DC are compatible with those of the CLDC. However, the GISS-DC has better ductility than the CLDC, this may be due to the smaller and more globular primary α-Al phase and rounder shaped-Si particle microstructures presented in the GISS-DC. Common shrinkage pores and defects were also observed by SEM from the fracture surfaces of both alloys.


2012 ◽  
Vol 184-185 ◽  
pp. 649-652
Author(s):  
Gui Fang Guo ◽  
Shi Qiong Zhou ◽  
Liang Wang ◽  
Li Hao ◽  
Ze Guo Liu

The effects of electron beam welding on the residual stresses of welded joints of pure aluminum plate 99.60 are studied by through-hole-drilling and blind-hole-drilling method. Meanwhile, based on the thermal elastic-plastic theory, and making use of ANSYS finite element procedure, a three - dimensional finite element model using mobile heat source of temperature and stresses field of electron beam welding in pure aluminum is established. The welding process is simulated by means of the ANSYS software. The results show that the main residual stress is the longitudinal residual stress, the value of the longitudinal residual stress is much larger than the transverse residual stress. But the residual stress in the thickness is rather small. And in the weld center, the maximum value of residual stresses is lower than its yield strength. The simulation results about the welded residual stresses are almost identical with the experimental results by measuring. So the research result is important to science research and engineering application.


2009 ◽  
Vol 83-86 ◽  
pp. 237-243
Author(s):  
Mohammad Sedighi ◽  
B. Davoodi

Due to the intense concentration of heat in the welding process, residual stresses are produced in the specimen. One of the most effective ways to relief welding stress is Post Welding Heat Treatment (PWHT). In this paper, finite element method is employed to model and analyze PWHT for two pass butt-welded SUS304 stainless steel pipe. In this simulation, firstly, the welding process has been modeled. Then the stress distribution of the specimen has been transferred to a second analysis for stress relaxation modeling. Norton law is used to investigate creep in stress relief process. Experimental tests are also carried out to verify the effectiveness of the proposed numerical models. The hole drilling method is used to measure the stress distribution in the specimen. The residual stress distribution data before and after PWHT are compared to investigate the effect of heat treatment on residual stress. Based on the modeling and experimental results, the tensile and compressive stresses distributions have been reduced. They are in a reasonable agreement with each other and prove the capability of the proposed modeling technique to simulate PWHT.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5738
Author(s):  
Nidal Alshwawreh ◽  
Baider Alhamarneh ◽  
Qutaiba Altwarah ◽  
Shamel Quandour ◽  
Shadi Barghout ◽  
...  

Thermal processing of all aluminum alloy conductors (AAAC) is an important step that is performed to enhance the electrical and mechanical properties after the drawing process. In these 6xxx alloys, mechanical strength and electrical conductivity are normally two mutually exclusive properties. With the increased demand for high performance power conductors, it is important to understand and control microstructural evolution processes (e.g., recovery and the formation of nanoscale precipitates) in these alloys for better electrical and mechanical characteristics. In this study, heat treatment was performed on as-drawn 6201 AAAC wire conductors. The variations in tensile strength and electrical resistivity were quantitatively studied as a function of both the treatment temperature and holding time. Two wire diameters commonly used in the manufacturing of medium and high voltage power cables were used: 1.7 mm and 3.5 mm. From the obtained data, significant changes in the electrical resistivity and tensile strength were observed with increasing the treatment time. For both wire diameters, it was observed that the correlation between strength and resistivity can be described by a simple exponential relationship. This link could be useful in predicting mechanical strength by monitoring electrical resistivity variations during industrial heat treatment of AAAC wire conductors.


2018 ◽  
Vol 53 (7) ◽  
pp. 494-503 ◽  
Author(s):  
Iman Alinaghian ◽  
Saeid Amini ◽  
Mohammad Honarpisheh

In recent decades, ultrasonic vibrations are used in manufacturing processes because they can improve tool life, material performance, and quality. One of them which can be integrated with ultrasonic vibrations is friction stir welding called ultrasonic assisted friction stir welding. In previous studies, the effect of ultrasonic vibrations on the mechanical, metallurgical, and thermal properties was investigated and there is not any residual stress investigations on ultrasonic assisted friction stir welding. Since residual stress plays an important role in performance and stability of components, the influence of ultrasonic power on the longitudinal residual stress in friction stir welding is investigated in this work. In spite of residual stress, tensile strength and quality of weldment were investigated as complementary terms to ensure successful performance of ultrasonic assisted friction stir welding. The findings indicated that high-frequency vibrations with power of 200 W can reduce the maximum tensile residual stress about 45% and significantly increase tensile strength. Also, ultrasonic vibrations prevent defect such has voids and tunnel in weld zone due to peening effect in ultrasonic assisted friction stir welding.


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