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 Posted: Thu 22:21, 13 Jan 2011 Post subject: ugg stivali 34CrMo4 quenched _3147 Failure Analysi |
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Cracking Analysis of 34CrMo4 quenched
Ministry of the surface contraction is greater than the heart contraction, the center would obstruct the surface contraction, the elastic stretching the surface, while the elastic surface of the heart-mail compression. Thus, cooling the surface of pre-existing stress state is tensile stress, the center there is the late stress l cooling surface temperature decreased gradually cooling rate is small, while the Ministry of cooling the heart to accelerate, then the surface of the heart in turn hinder the contraction of the Ministry, the Ministry of the heart flexible done, the Ministry of the heart so that the surface elastic compression, the results of internal stress change of direction,[link widoczny dla zalogowanych], the surface compressive stress, the center for the tensile stress. Cooling the residual stress state below the end of lap 1. Pull stupid Shí Figure l A weak pressure cylinder Benjamin fast quenching; boast the thermal stress Zhu (2) Stress: Stress, also known as phase transformation stress, rapid cooling by the time the workpiece surface and the center phase difference in the stress . Specific volume of martensite in steel largest minimum specific volume of austenite. Austenite to martensite transformation, the greatest change in specific volume, and the higher the carbon content of the specific volume changes of the more hardened too. Therefore,[link widoczny dla zalogowanych], quenching the surface first cooled to below the martensite, martensitic transformation occurs, the volume to bang Zhang | Heart Ministry had not changed, the surface is bound to hinder the expansion of the surface pressure, and 58 * Test L991 physical shad No. 5 Surface tension makes the heart department. With the change in temperature decreases the surface has been completed in most, the center point of the following before the cold began to martensite transformation. Therefore, the stress changes the picture shows the end surface of tensile stress, and heart Ministry of stress exists. Bu Tuqia stress points in the thermal stress diagram opposite. According to reference [4] that; lateral stress distribution of crack are: surface pressure forces blood from the drastic changes in surface stress occurs some distance from the stress becomes large tensile stress. Cracks in the tensile stress peak in the region, and then when the spread of the stress redistribution to the surface only. In summary, the alloy formation and quenching quenching stress crack on. 3.3 by discussing the causes of cracks above analysis, 34CrMo4 steel platform because of its lower carbon content, thus the stress during heat treatment has little effect on the organization. However, because of 34CrMo4 steel joined Cr, Mo, Mn, Si and other alloying elements, to decrease thermal conductivity. So when this steel quenched in water if the cooling, especially in winter, cooling water quenching, quenching the sample is bound to increase the thermal stress, the results will lead to the crack in the 60O ℃ water tempering, but also to promote the further development of the crack . However, when we changed the j square enamel quenching,[link widoczny dla zalogowanych], from water to oil cooling, tempering the water to air cooling, the crack can be eliminated. Thus, 34CrMo4 steel, cracks, excluding Second, we must factor in, mainly by quenching the result of heat stress. 3.4 Conclusion 34CrMo4 steel, cracks are mainly caused by the hardening heat stress. For better hardenability,[link widoczny dla zalogowanych], and less fire-looking steel during heat treatment, the slow cooling method should be used to reduce the cooling result of inadequate specimens scrapped. Reason for the low tensile strength of 3.5: On the problem of low tensile strength of steel 34CrMo4 reasons, we reviewed reference [1] I 30CtMoA indole production of steel, its chemical composition and mechanical properties of the production with West Germany the 34CrMo4 steel, basically. From the literature (1) 30CrMoA steel tempering temperature and mechanical properties of the relationship can be seen, different tempering temperature has a different tensile strength, when the tempering temperature of 5OO ℃, the tensile strength 1200N/ram,[link widoczny dla zalogowanych], When the tempering temperature of 6OO ℃ when the tensile strength 900N/ram. . From this we can be sure, 34CrMo4 steel tensile strength of the low tempering temperature phenomenon is caused by the inappropriate choice of tempering temperature structure when we changed from the 6OO ℃, 540 ℃, its tensile strength is needed to achieve standards of West Germany . 4 Results from 34CrMo4 steel analysis Cambodian language gave us such a revelation, that is, when the heat treatment of steel when we first analyze the chemical composition of the virtual heat treatment process in the role, to see how the hardenability, tempering without looking sex. Then formulated and reasonable heat treatment specifications, so as to effectively correct the results of a draw, which test for improving our efficiency levels and the second L for marriage with l j Yi Ning down. .... .... ... R. . . Reference l_ text-l metallurgical industry are \Actinide species of silver tone plate manual (Volume One). Industry Press Beijing stack of well-being of Taiwan l, l983, l702 Wang t On the main Pian. Metallurgy and Heat Treatment (the book). Hebei Institute of Technology, Shenyang Automotive Group 19803 South Treatment Plant put down support group to ask general ed. Hot Cheliwenpu. 1974l unremitting heat sensitive and Kui-shaped passage. Machine Industry Press maple. l985 An Yunfeng editor. Heat treatment technology. Shaanxi Institute of Acer machines. 1982
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