Papers by Keyword: Intermediate Annealing

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Authors: Christophe Sigli, H. Vichery, B. Grange
Authors: Wei Chen, Pi Zhi Zhao, Yu Li Zhou, Yan Feng Pan
Abstract: AA8021 aluminum alloy twin-roll cast strips with 7mm gauge were rolled to 3.8mm gauge sheets and given homogenization, further rolled into 0.55mm gauge foil stocks with intermediate annealing. This paper investigated the influence of homogenization conditions on microstructures of foil stocks in detail. The results show that, for the foil stock made from the sheet without homogenization, the grain structure is partially recrystallized. While the grain structure of foil stock made from the sheet with medium temperature homogenization is fully recrystallized, but it is coarse near sheet surface. However, foil stock made from the sheet with high temperature homogenization has fine and uniform recrystallized grain structures. The differences of grain structures among these three kinds of foil stocks can be understood by the variation in solid solution content of Fe, Si, Mn and distribution of intermetallic compounds. The optimized homogenization condition was adopted by our plant to produce foil stock, and its grain structure was fine and uniform. The surface quality of final aluminum foil rolled from the foil stock could meet high grade requirements of customers.
Authors: Yan Hui Guo, Zhao Dong Wang, Guo Dong Wang, Xiang Hua Liu
Authors: Sang Ho Lee, Mok Soon Kim, Dong-su Jung, Jeong Whan Han, Byung Don You
Authors: Yi You Tu, Xiang Liang Liu, Min Da Zhang, Jian Jun Zhang
Abstract: Effect of intermediate annealing and final annealing on microstructures and properties of Al3003+Zn sheets is studied. The microstructure of aluminum sheets is observed by Optical Microscope and Transmission Electron Microscope,and the sagging resistance of aluminum sheets is tested by sagging test rig. The results indicate that complete recrystallization can be obtained after intermediate annealing at 380°C,and the recrystallization grain size of aluminum sheets reduces appreciably when annealing temperature rise. The sagging distance of aluminum sheets decreases proportionally with the grain size. Final annealing after final cold rolling eliminates subgrain structure of aluminum sheet, and improves sagging resistance of aluminum sheets observably.
Authors: Wen Ting Wei, Xun Peng Qin, Song Deng
Abstract: This paper studies the influence of the intermediate annealing on deformation ability of the cold rolled ring. The results show that: intermediate annealing can improve the ability of plastic deformation of the cold rolled ring, ring rupture occurred after 62.5% thickness reduction, on the other side the ring suffering intermediate annealing still be intact by rolling to upon 64.8% thickness reduction. The mechanism of the intermediate annealing improving deformation ability of cold rolled ring is explored by using optical microscopy, scanning electron microscopy, micro hardness tester and other materials characterization methods. It is found that after intermediate annealing, the amount of carbide particles significantly reduce and the hardness decrease. Meanwhile, dissolution of partial carbides occur during the cold ring rolling process, and with the increasing of the cold rolling deformation, the quantity of the dissolution of cementite in pearlite will increase, which resulting in the improvement of the deformability of the cold rolled ring.
Authors: Fei Han, Gao Yong Lin, Zai Lin Wang, Da Shu Peng
Abstract: Intermediate annealing to stainless steel can eliminate the residual stress, and improve plasticity and ductility effectively, but oxidation after different annealing processes has considerable difference. In this research, three annealing processes, low temperature annealing with ordinary heat treatment furnace, high temperature annealing with ordinary heat treatment furnace and high temperature bright annealing, were used to gain insight into the mechanics of intermediate annealing. Specimens of 304 austenitic stainless steel sheets were adopted in the intermediate annealing experiments which pre-deformation was 15%. The specimens’ surface microstructure were observed by scanning electron microscope (SEM), and the specimen oxidation, which happened in the annealing process, were also analyzed. The results show that bright annealing must be adopted in high temperature annealing.
Authors: Tricia A. Bennett, Jurij J. Sidor, Roumen H. Petrov, Leo Kestens
Abstract: Roping was investigated in two 6016 aluminium alloys that exhibit different levels of susceptibility to its occurrence. The level of roping is lower, as manifested by the less pronounced (roping) lines on the surface, in the GR material compared to the BR case. Through-process characterization of GR and BR materials by means of electron backscatter diffraction (EBSD) reveals similarities in the grain size, (grain) orientation texture and the spatial distribution of {100} <001> Cube grains up to, but not including the T4 state. Cube grains in the T4 state are spatially banded in the BR material but more uniformly distributed in the GR case. It was found that the thermo-mechanical treatments prior to the T4 state account for the difference in spatial distributions of Cube grains and hence, the different roping behaviours exhibited by these materials.
Authors: Kenta Suzuki, Daisuke Shimosaka, Tomohiro Sasaki, Yasuyuki Owada, Shuhei Kuroiwa, Toshiya Anami
Abstract: The effects of Ni content and intermediate annealing conditions on recrystallization behavior during brazing heat treatment of Al–Fe–Ni–Si alloys fin stocks of automotive heat exchangers were studied by means of microstructural analysis. Following brazing heat treatment, coarsening of recrystallized grain structure was observed in both 0.5% Ni and 1.0% Ni fin stocks, which were intermediately annealed in a salt bath. This coarsening was particularly marked in 1.0% Ni fin stocks. The results of the microstructural observations indicated that fine dispersoids were heterogeneously dispersed in 1.0% Ni fin stocks that were annealed at 550°C for 10 s in a salt bath. It was proposed that the preferential recovery and recrystallization during the brazing heat treatment in the low density area of the fine dispersoids contributed to the larger recrystallized gain structure. The coarse recrystallized grains obtained by controlling the salt bath annealing conditions are expected to contribute in improving the properties of Al–Fe–Ni–Si alloy fin stocks of automotive heat exchangers.
Authors: Xiao Feng Wang, Ming Xing Guo, Ling Yong Cao, Li Cui, Ji Shan Zhang, Lin Zhong Zhuang
Abstract: In order to improve formability, it is practicable to control the texture through adjusting process parameters. This work describes the evolution of microstructure and texture during thermomechanical processing of Al-Mg-Si-Cu alloy. With the change of deformation conditions, both the microstructure and texture change dramatically. After hot rolling from 90 mm to 7.5 mm, H and E texture components in the surface layer become dominant due to non-uniform deformation. And then with the increasing of cold rolling deformation from 7.5 mm to 4.0 mm, the texture components gradually change from shear texture to typical fcc texture, i.e. Copper, S and Brass textures, and their intensities also increase. And these texture components transform to some uncommon texture components after intermediate annealing, including {013}<001>, {001}<130>, Goss texture, {556}<110> and {111}<110> texture, not as the typical recrystallization texture components. Continually giving a cold rolling deformation from 4.0 mm to 1.0 mm, not only Copper, S, Brass textures, but also Goss texture due to the lower deformation can be found in the alloy sheet. The high temperature solid solution treatment can result in the complete recrystallization and the formation of recrystallization texture, Cube, Goss and R texture, which results in the high formability of experimental alloy.
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