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 Posted: Thu 22:23, 13 Jan 2011 Post subject: ugg stivali Of high strength steel weld properties |
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Of high strength steel weld 45CrNiMoV of performance factors
TEM thin film sample is parallel to the metallographic sample box in the direction of grinding phase, and with molybdenum cut wire cutting machine into 0.3ram thick slices, mechanically thinning, the use of double-jet electrolytic polishing ( l5 alcohol solution for the acid electrolyte) made. With H-800 electron microscope analysis. Structural analysis shows that, l is the structure of the sample No. martensite, as shown in Figure 3. Lath morphology is still clearly visible. In the sample No.】 also found that twin martensite, but very few. 】 5,[link widoczny dla zalogowanych], samples from the lath martensite and lower bainite and a small amount. Roar's body composition. Can also be seen, j number and width of different slab】 5, l number of narrow, l5 number wide. \field image and diffraction pattern of the village title [0113a / / E001us. [ol1] port / / [120] s, [2l1 / / [52Ous phase analysis showed that the sample No.】 carbide is a multi-orientation within the dispersed Fesc. Weld also found a small amount of FeMo phase. FesC dominated by the grain boundary, but a small number. there is a small amount of Iv [∞ Ce and CaO · MgO · SiO2 inclusions. the first and second perpendicular to each other in space star grid distribution. l5 number of test bars and grain boundaries within the crystalline precipitates is Fe3C, in addition to a small amount of AI2O3, CaO · Iv [gO · SiO2 and Fe3O inclusion. 5,[link widoczny dla zalogowanych], 1995 observation of the physical test also found that spit Fe phase is also often CaO · MgO · SiO2 core and coherent nucleation and growth of the terrain shown in Figure 4. 3 discusses the degree of carbon steel, low-Jin Gaoqiang welding, the welded joints are often low-intensity matching adopted, the carbon content of the weld than the base metal. Its purpose is to sacrifice part of the weld strength, in exchange for a higher toughness. This is the safe operation of welded structures is beneficial. In this experiment, the carbon content of test wire lower than the base metal, a low-strength matching of welded joints. As the carbon content of different wire, different forms of joint slope VI, the actual carbon content of the weld were significantly different. For such a weld, through the same heat treatment the weld structure and mechanical properties were significantly different.】 No. weld specimens, quenched in oil can be obtained under the uniform martensite. The tempered martensite after tempering. and by the map】 Figure 3 shows a very fine lath martensite, carbides within the grain orientation was more evenly distributed. these are beneficial to the toughness of the weld is not conducive to the spread of crack. the welds with excellent mechanical properties . l5 weld No. sample, quenching in oil can not be uniform under lath martensite. in the weld contains a considerable number of changes in the temperature of the product: upper bainite and lower bainite. When the Markov When the body with upper bainite is not conducive to the performance of the weld J: bainite is thick iron tangled bodies, the hardness is much lower than the tempered martensite, and between the thick rod lath carbide precipitation, reduce the binding strip to ask. crack propagation in the upper bainite is easier, so the weld strength and toughness are low. Second,[link widoczny dla zalogowanych], the original austenite grain No. 1 smaller samples, which for the weld toughness advantage. When the crack propagation in fine-grained weld. crack front will encounter more grain boundaries. quite frequently consume more energy to change the direction of extension, on the other. crack tip plastic zone will contain more grains, the stress concentration decreased significantly. crack to continue to expand will consume more energy, but also conducive to the toughness of the weld. The above shows that low-intensity match with carbon high strength steel welding, the welding wire selection, the choice of form and groove the choice of welding parameters,[link widoczny dla zalogowanych], in order to obtain the best weld composition, structure, resulting in excellent weld strength and toughness has a direct impact in matching. Conclusions (1) matching welding in low strength carbon high strength steel, the correct choice of the chemical composition of welding wire,[link widoczny dla zalogowanych], welding groove forms and parameters, to obtain good matching between weld strength and toughness, these are important factors. (2) uniform weld metal lath martensite, with the best comprehensive mechanical properties. weld should be avoided on the bainite (3) Cao · MgO · SiO2 inclusions can be Ah Fe a e phase crystallization of the core. l king list fields. physical examination, 1994l (6): 2 king list fields . the physical test, 19 951 (1), 3 Wang Meng Tian. high-strength gas welding wire, to be published the date of receipt of manuscripts; January 1994 l】】 6 References
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