scholarly journals Peen forming and stress peen forming of 2024-T3 aluminum sheets. Part 2: eigenstrain analysis

2021 ◽  
Author(s):  
Hong Yan Miao ◽  
Martin levesque ◽  
Frederick Gosselin
Keyword(s):  
Plastic Anisotropy ◽  
Rolling Direction ◽  
Initial Stresses ◽  
Plastic Strains ◽  
Aluminum Sheets ◽  
Peen Forming ◽  
Rolled Aluminum ◽  
Bending Loads ◽  
Geometric Preference ◽  
Different Sources

In this study we use the theory of eigenstrains to investigate how different sources of anisotropy affected the results of shot peen forming experiments reported in Part~1. The specimens consisted of 4.9 mm thick 2024-T3 aluminum sheets uniformly shot peened on one face that were either free to deform or held onto a prestressing jig during peening. Potential sources of anisotropy included the plastic anisotropy of rolled aluminum, anisotropic initial stresses that redistribute when their equilibrium is disturbed by peenning, the geometry of the specimens, and externally applied prestress. For the alloy and peening conditions considered, plastic anisotropy had no discernable influence on the resulting shape of the peen formed specimens. Initial residual stresses, on the other hand, caused slightly larger bending loads in the rolling direction of the alloy. Although the magnitude of these loads was approximately 30 times smaller than peening-induced loads, it was sufficient to overcome the geometric preference for rectangular sheets to bend along their long side and cause all unconstrained specimens to bend along the rolling direction instead. Once the sheets started to deform, larger plastic strains developed in the bending direction. We show that this effect is equivalent to that used in the variant of the process called stress peen forming where parts are elastically prestressed during peening to obtain larger plastic strains in directions in which the material is stretched.

Deformation, recrystallization and plastic anisotropy of asymmetrically rolled aluminum sheets

2010 ◽  
Vol 528 (1) ◽  
pp. 413-424 ◽  
Author(s):  
Jurij Sidor ◽  
Roumen H. Petrov ◽  
Leo A.I. Kestens
Keyword(s):  
Plastic Anisotropy ◽  
Aluminum Sheets ◽  
Rolled Aluminum

Residual Stress Distribution through Thickness in Cold-Rolled Aluminum Sheet

2014 ◽  
Vol 622-623 ◽  
pp. 1000-1007 ◽  
Author(s):  
Nobuyuki Hattori ◽  
Ryo Matsumoto ◽  
Hiroshi Utsunomiya
Keyword(s):  
Residual Stress ◽  
Friction Coefficient ◽  
Stress Distribution ◽  
Aspect Ratio ◽  
Rolling Direction ◽  
Contact Length ◽  
Residual Stress Distribution ◽  
Aluminum Sheet ◽  
Rolled Aluminum ◽  
Cold Rolled

Distribution of residual stress through the thickness of a cold-rolled aluminum sheet is analyzed by the elastic-plastic finite element method under plane strain condition. Single-pass rolling of 2mm-thick aluminum sheet is considered. Influences of roll diameterD, reduction in thicknessr, and friction coefficientμare investigated. When the friction is low (μ= 0.1 and 0.2), and the case with smaller rolls (D= 130 mm) and low reduction (r= 5%), the residual stress in the rolling direction is compressive at surface and tensile around the layer quarter deep from the surface. While in the case with larger rolls (D= 310 mm) and high reduction (r= 30%), the stress is tensile at surface and the stress decreases to compressive with increasing depth from surface. In other words, with low friction, the residual stress distribution strongly depends on the aspect ratio (contact length / mean thickness) of the roll bite. On the other hand, when the friction coefficient is high (μ= 0.4), the residual stress is compressive at surface regardless of roll diameter and reduction. It means that the friction makes the residual stress at surface more compressive. It is found that the relationship between the residual stress at surface and the aspect ratio is almost linear, and that the slope depends on the friction coefficient.

scholarly journals Effects of iron silicon on ears in deep drawing of rolled aluminum sheets

1968 ◽  
Vol 18 (2) ◽  
pp. 106-113 ◽  
Author(s):  
Tsuneo TAKAHASHI ◽  
Osamu NAKAMURA ◽  
Masaoki HASHIMOTO
Keyword(s):  
Deep Drawing ◽  
Iron Silicon ◽  
Aluminum Sheets ◽  
Rolled Aluminum

scholarly journals Effects of Initial Precipitate on Shear Deformation during Asymmetric Rolling of Al-Mg-Si Alloy: Texture and Formability

2020 ◽  
Vol 58 (10) ◽  
pp. 703-714
Author(s):  
Wonkee Chae ◽  
Bong-Kyu Kim ◽  
Jongbeom Lee ◽  
Jun Hyun Han
Keyword(s):  
Shear Deformation ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Texture Evolution ◽  
Plastic Anisotropy ◽  
Rolling Direction ◽  
Strain Ratio ◽  
Equivalent Strain ◽  
Asymmetric Rolling ◽  
Plastic Strain Ratio

Al-Mg-Si alloy was rolled asymmetrically at several temperatures to apply shear deformation, and the effects of the initial precipitate on shear deformation, texture evolution, formability, and plastic anisotropy were studied. Texture was analyzed using a EBSD, and the formability and plastic anisotropy of the specimen were evaluated using the value and value calculated from the plastic strain ratio (r-value) which was determined from the change in the length of the specimen during tensile deformation. Asymmetric rolling induces a larger equivalent strain than symmetric rolling, and the equivalent strain increases as the asymmetric rolling temperature increases. When a specimen with peak-aged initial precipitates was asymmetrically rolled, less shear deformation occurred at room temperature than in a solution-treated specimen without initial precipitates. In contrast, a larger shear deformation occurred at high temperatures (500°C). With asymmetric rolling at room temperature, the specimens without initial precipitates had higher formability and lower plasticity, while for asymmetric rolling at high temperature, the specimens with initial precipitates had higher formability and lower plastic anisotropy. This is due to the <111>//ND texture, such as {111}<110> and {111}<112> orientation that has similar and high r-values at 0°, 45°, and 90° to the rolling direction, developed by the shear deformation that occurred during asymmetric rolling.

scholarly journals Peen forming and stress peen forming of 2024-T3 aluminum sheets. Part 1: 3D scans and residual stress measurements

2021 ◽  
Author(s):  
Hong Yan Miao ◽  
Pierre A. Faucheux ◽  
Martin levesque ◽  
Frederick Gosselin
Keyword(s):  
Residual Stress ◽  
Hole Drilling ◽  
Progressive Deformation ◽  
Stress Measurements ◽  
Hole Drilling Method ◽  
Aluminum Sheets ◽  
Aspect Ratios ◽  
Peen Forming ◽  
Metal Bilayers ◽  
3D Scans

Aluminum skins on the lower wings of most commercial aircraft are shaped using shot peen forming. This process, which involves bombarding the skins with hard shot, uses nonuniform plastic flow to induce curvatures---in the same way that differential expansion makes metal bilayers bend when heated. Here, we investigate experimentally how constraining conditions affect the final shape of peen formed parts. We report peen forming experiments for 4.9 mm thick rectangular 2024-T3 aluminum sheets of different aspect ratios uniformly shot peened on one face with a low intensity saturation treatment. Some specimens were free to deform during peening while others were elastically prestressed in a four-point bending jig. For each aspect ratio and prestress condition, residual stresses were measured near the peened surface with the hole drilling method. Additional residual stress profiles were also obtained with the slitting method. The residual stress measurements show that the progressive deformation of unconstrained specimens had the same effect as an externally applied prestress. For the peening conditions investigated, this progressive deformation caused unconstrained strips to exhibit curvatures 33% larger than identical strips held flat during peening. Furthermore, we found that the relative importance of material anisotropy and geometric effects did determine the bending direction of unconstrained specimens.

scholarly journals Experimental and Computational analysis of springback in dual phase steels

2021 ◽  
Vol 26 (2) ◽  
pp. 137-145
Author(s):  
Rodolfo Rodríguez Baracaldo ◽  
Yeison Parra-Rodríguez ◽  
José Manuel Arroyo-Osorio
Keyword(s):  
Elastic Recovery ◽  
Plastic Anisotropy ◽  
Microstructural Analysis ◽  
Rolling Direction ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
Dual Phase ◽  
Characteristic Region

In this work the comfortability of dual-phase automotive steel DP600 is studied through uniaxial tensile tests and V-die bending tests in different directions relative to the rolling direction. A microstructural analysis was also carried out in each characteristic region of the deformation zone, evidencing the changes in the morphology of the microstructure grains. Additionally, the plastic anisotropy of the material was studied by implementing the constitutive anisotropy models known as Hill-48 and Barlat-89. The results showed an increase in elastic recovery at 45 ° and 90 ° from the rolling direction. This variation can be attributed to the morphology of the martensite that created preferential location zones within the material during the rolling process. The two models Hill-48 and Barlat-89 correctly describe the yield surface and the plastic anisotropy obtained in the experimental tests carried out. The simulation using the finite element method and the Hill-48 model gave satisfactory results in the prediction of the elastic recovery as compared to the experimental results obtained with the V-die bending test.

scholarly journals Prediction of Earing of Cross-Rolled Al Sheets from {h00} Pole Figures

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 192
Author(s):  
Marton Benke ◽  
Bence Schweitzer ◽  
Adrienn Hlavacs ◽  
Valeria Mertinger
Keyword(s):  
Deep Drawing ◽  
Plastic Anisotropy ◽  
Rolling Texture ◽  
X Ray Diffraction ◽  
Cross Rolling ◽  
X Ray ◽  
Aluminum Sheets ◽  
Pole Figures ◽  
Cold Rolling Texture ◽  
First Time

The plastic anisotropy of rolled Al sheets is the result of a crystallographic texture. It leads to the formation of uneven cup heights during deep-drawing, which is called earing. A new, simple and rapid method had been previously developed by the authors to predict earing directly from {h00} pole figures. In the present manuscript, this method is applied to cross-rolling for the first time. 5056 type aluminum sheets were unidirectionally- (conventionally) and cross-rolled from 4 to ~1 mm thickness in 6 or 12 passes. Earing was predicted from recalculated {200} pole figures obtained after X-ray diffraction texture measurements. The results were validated by deep-drawing tests. It is shown that the proposed method predicts the type (locations of ears) and magnitude of earing with satisfactory results. However, a different scaling factor must be used to calculate the magnitude of earing for cross-rolling than for unidirectional rolling even if all other parameters (including cold rolling, texture measurements, and deep-drawing) are the same. This is because the cross-rolled sheets exhibit a similar type but weaker earing compared to the unidirectionally rolled samples.

Three Surface TEM Observations of Cold Rolled 1100 Aluminum

1981 ◽  
Vol 39 ◽  
pp. 50-51
Author(s):  
D. L. Rohr ◽  
S. S. Hecker
Keyword(s):  
Room Temperature ◽  
Rolling Direction ◽  
Plastic Strains ◽  
Thickness Direction ◽  
Sheet Surface ◽  
Thin Foils ◽  
Cold Rolled ◽  
Rolled Plates

As part of an on-going study of 1100 Al at large plastic strains, we have examined cold-rolled samples from three orientations; through the sheet surface, and in the thickness direction along the rolling direction (RD) and transverse to the RD. Cell and subgrain sizes were determined in the same manner as for the earlier work.The starting plates of 1100 Al were annealed at 500 C and then rolled at room temperature to various thicknesses. These rolled plates were used to produce final samples rolled to 0.5 mm thickness with 62, 80, and 90% reductions. Thin foils were produced by lapping and jet electropolishing. A method was developed to make thin foils perpendicular to the sheet by lapping small pieces of sheet (1 mm wide) edgewise from both edges. This produces sheet 0.25 mm thick by 0.5 mm wide which were mounted between two 0.25-mm-thick 1100 Al disks 3 mm in dia. These disks had been slitted in the center to have slits ≪ 0.5 mm wide.

Sign in / Sign up

Export Citation Format

Share Document