Residual stresses in aluminium alloy friction stir welds

There are many drawbacks of traditional mold manufacturing technology, especially for dies used on largescale hydraulic press, such as poor forging penetration, high difficulty of open die-forging process of modules, inferior hardness after heat treatment, high cost, massive waste of invalid forging dies, and so on. Therefore, a new method of mold making is put forward in this paper, which is to do surface welding on casting-steel. The FEM simulation experiments were done to establish a simplified finite element model of the surface welding mold based on JXZG castingsteel. Then, the thermal cycle curve method was used to simulate the surface welding and tempering process. Meanwhile, the temperature field and residual stress field under different welding thickness were analyzed. The finite element modal of landing gear used in a large civil aircraft was established, and then elastic-plastic finite element method was utilized to simulate the forming process of billet and to analyze the temperature field and residual stress distribution of different time. The results demonstrated that FEM could simulate the actual process of surface welding on casting-steel effectively. The equivalent stress close to welding line decreased when the welding thickness inclined, and then it leveled out when the welding thickness was 15 mm; on contrary, the equivalent stress far from welding line increased when the welding thickness declined and the impact of weld pass on casting-steel matrix enlarged which increased the possibility of defects when the casting-steel was used. In sum, when the impact of welding thickness and the cost of mold making are taken into consideration, 16 mm was chosen as the optimal surface welding thickness under given working conditions of landing gear.

show abstract

“…Finally, Fig. 7 shows the comparison of simulation and experiment results which proved the usability of our optimal thermal cycle cure [17,18].…”

Section: Fem Simulation Of the Surface Welding Processmentioning

confidence: 78%

Optimization of welding thickness on casting-steel surface for production of forging die

Zhou

Zhang

2014

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…The residual stress profile predicted by the simulation, however, is narrower than the experimental one. At 3.4 mm from the centerline on the advancing side, the residual stress rises to 140 MPa, and on the retreating side, the residual stress rises to 114 MPa at approximately the same distance, developing the M-shape profile characteristic to aluminum alloys ( Ref 22,25). The M-shape does not appear in the experimental residual stress profile, but the distance between experimental measurements is generally too broad to distinctly reveal this feature.…”

Section: Residual Stressmentioning

confidence: 98%

Using a Coupled Thermal/Material Flow Model to Predict Residual Stress in Friction Stir Processed AlMg9Si

Hamilton

Węglowski

Dymek

et al. 2015

J. of Materi Eng and Perform

View full text Add to dashboard Cite

A coupled thermal/material flow model of friction stir processing is developed for friction stir processing of an as-cast AlSi9Mg aluminum alloy. By capturing material flow during processing, an asymmetric temperature distribution is generated with higher processing temperatures on the advancing side than on the retreating side. The temperature distribution from the coupled model is then incorporated into a thermomechanical model to predict the residual stress state after processing. These numerical results are compared with the residual stresses experimentally measured by the trepanation method. Experimental results show that the tensile residual stresses are higher on the advancing side than on the retreating side. The simulation successfully captures the asymmetric behavior of the residual stress profile, and the predicted maximum residual stress values show relatively good agreement with the experimental values. The simulated profile, however, is narrower than the experimental profile, yielding a smaller region of tensile residual stresses around the process zone than experimentally observed.

show abstract

“…The plates are joined with an AISI1040 quenched steel tool with a shoulder diameter of 20 mm and a conical pin with a height of 3.8 mm, a diameter of 6.2 mm, and a conical angle of 30°. The tool is running with a tilt angle of 2°, a rotating speed of 1400 rpm, and a traversing speed of 70 mm/min, and hence the process resembles a hot welding condition [9], meaning that the microstructure in the TMAZ will be substantially affected by the FSW process [8].…”

Section: The Fsw Experimentsmentioning

confidence: 99%

“…However, a more thorough comparison of the different residual stress measurements as well as the applied methods as the one presented here has not been given in literature before. Furthermore, Price et al [3] X-ray diffraction 100 120 Altenkirch et al [4] Neutron and synchroton X-ray diffraction 125 190 Reynolds et al [5] Neutron diffraction 80 90 Steuwer et al [6] synchroton X-ray diffraction 100 175 Dubourg et al [7] Neutron diffraction 150 175 Deplus et al [8] Cut-compliance 50 110 Carlone et al [1] Contour method 50 100…”

Section: Introductionmentioning

confidence: 99%

Assessment of the Contour Method for 2-D Cross Sectional Residual Stress Measurements of Friction Stir Welded Parts of AA2024-T3—Numerical and Experimental Comparison

Sonne

Carlone

Hattel

2017

Metals

View full text Add to dashboard Cite

Abstract:The contour method is one of the newest techniques for obtaining residual stress fields from friction stir welded (FSW) parts, experimentally. This method has many advantages; however, edge effects coming from the process itself might introduce artifacts in the obtained results, and this was slightly touched upon in the very first paper on the method. This concern is further assessed in the present work, where the contour method is compared with the results that were obtained numerically via a thermomechanical model and experimentally via the cut-compliance method. For the two-dimensional (2-D) cross sectional map obtained by the method, peak stresses in tension are observed in the mid-section of the FSW butt-welded plates at the distance of the tool radius from the centerline. The corresponding numerical simulation indicates the same behavior because of the particular clamping conditions, and consequently this should not be interpreted as a misleading result of the contour method. Edge effects from the cutting process involved in the contour method should, however, be taken into consideration, most likely resulting in the residual stresses observed near the surfaces of the cross section being less extreme in reality than observed.

show abstract

Residual stresses in aluminium alloy friction stir welds

Cited by 59 publications

References 29 publications

Optimization of welding thickness on casting-steel surface for production of forging die

Optimization of welding thickness on casting-steel surface for production of forging die

Using a Coupled Thermal/Material Flow Model to Predict Residual Stress in Friction Stir Processed AlMg9Si

Assessment of the Contour Method for 2-D Cross Sectional Residual Stress Measurements of Friction Stir Welded Parts of AA2024-T3—Numerical and Experimental Comparison

Contact Info

Product

Resources

About