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Wire Rod for Drawing Fracture

Surface rolling, you can not eliminate the phenomenon of mixed crystal; ③ rod part in the austenite recrystallization zone of mixed grain when rolling. A mixed grain structure of the wire rod in the drawing are inconsistent when the internal organization of the deformation,[link widoczny dla zalogowanych], so that drawing performance degradation, likely to cause stress concentration, leading to drawing fracture. 4 Conclusion normal ER7o6 Figure 5 rod microstructure IOOXFig. 5ThenormalmlcrostructureofwirecoilofER7O6 (continued on page 156) Wei Jianzhong, etc.: metallographic sample preparation and analysis techniques and methods 4DIC the practical application of differential interference contrast method (DIC) in the application of metallographic study was relatively small. Simply speaking, DIC technology to achieve the sample surface composition of different organizations on the height of the tiny differences in color contrast to the differences with the image in the form of conversion. The image has a sense of relief,[link widoczny dla zalogowanych], with rich colors in general,[link widoczny dla zalogowanych], the erosion of the sample can not be observed. In the study of lead-free solder on the organization of intermetallic compounds is a basic item, in bright field samples must be carried out under the observation of the erosion. The tissue is very soft solder, the sample surface deformation layer prone to erosion effect is usually not very good. At this point, the use of different compounds and the substrate in the hardness difference in performance caused by a high degree of sample preparation on the surface of small differences, the use of DIC image technology can get better results, shown in Figure 5. Figure 5 lead-free solder intermetallic compound Fig. 5Intermetalliccompoundinlead-freesolder However, DIC technology is not reduced sample preparation requirements, but is higher, this means that the sample grinding, polishing requirements. Scratch under the DIC technique glance. Defects in sample preparation, at this point is outstanding. Center in Figure 6 Figure 6 lead-free solder intermetallic compound Fig. 6Intermetalliccompoundinlead-freesolder position, with a huge compound was 120. Angle of a scratch clearly visible. References: [1] GB/T13298-1991,[link widoczny dla zalogowanych], metal microstructure testing method [s]. [2] Yao Hung years. Metallographic methods fM-]. Beijing: China Industry Press, 1963. [3] Shen Guiqin. OM Technology fM-]. Beijing: Beihang University Press, 1992. [4] Huang Zhifeng, Liu sent Joe, Liao Changbai. Metallographic sample preparation of sintered metal [J]. TESTING A physical volumes, 2000,36 (1) :21 - 23. [5] He Hongmei. Metallographic sample preparation process causes deformation layer and Countermeasures EJ]. TESTING A physical volumes, 2002,38 (10) :458 - 459. E6] \Color metallography techniques [M] + Beijing: National Defence Industry Press, 1987. [7] CHEN Xiang, Song Jinsheng, Li Yan Cheung. Differential interference contrast microscopy method in material analysis IJI. Experimental Technology and Management, 2003,2 o (3) :19-23. [8] Mei Yang, Ying Liu, Tu Ming Jing. High performance NdFeB permanent magnet and a key way to mouth]. Magnetic Materials and Devices, 2002,33 (1) :32-34. (Continued from page 148) The above results show that, ER7O6 broken rod and wire rod drawing the chemical composition and the type and size of inclusion has nothing to do with the wire rod surface defects and mixed grain structure has a direct relationship. 5 improvements (1) To ensure the smooth defect-free rod, slab surface must ensure complete elimination of any defects should be reasonable to meet the rolling requirements. (2) heating temperature is too high to form the mixed grain structure, can reduce the heating temperature to ensure uniform and fine grain austenite, followed by controlled cooling process for the original to provide a good organization, appeared before the mixed Rolling】 56 * crystal, can be solved by increasing the heating temperature. In the rolling process due to mixed crystal can be identified through the simulation test recrystallization curves under different deformation conditions to determine recrystallization temperature curve in order to avoid the rolling process of partially recrystallized austenite area. (3) For the austenite grains as small as possible, should be appropriately reduced spinning temperature, the spinning temperature is set in a narrow temperature range, which is conducive to be easy to pull out of uniform and fine organization. References: [1] GB/T3429--2OO2, welded steel wire rod [S]. E2] Yangren Jiang,[link widoczny dla zalogowanych], Yang Zheng. Q235A channel analysis on defects [J]. Physical tests, 2003, (5) :28-29.

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