Process Research of Rectangular Aluminium Square Tube
Sep 09, 2021
The heat of deformation in the middle of the rectangular aluminum square tube is relatively large, and the heat of the rectangular aluminum square tube is relatively large. The shape of the middle part of the material is loose, and the phenomenon of middle bulging may occur. Therefore, the setting of the plate shape parameters must ensure that the exit plate shape is flat and the middle part is slightly tighter than the sides, that is, to maintain a certain middle height, and a reasonable transition of the plate shape parameters between passes must be considered. The actual rolling deformation zone of the rectangular aluminum square tube is mostly in a mixed lubrication state. The boundary film ruptures of the micro convex body in the deformation zone due to the excessively high contact pressure, resulting in direct metal contact. At this time, a part of the pressure in the deformation zone is borne by the fluid. In the other part, the thickness of the oil film in the forming area is borne by the contacting micro-protrusions and decreases with the increase of the reduction rate. at the same time. In the high-speed rolling state, a large amount of deformation heat will cause the deformation temperature to rise, the thermal movement of the lubricating oil molecules will increase, and the directional adsorption will decrease. The strength of the oil film decreases, and even the oil film ruptures. The metal surface begins to scratch, and the absolute temperature at this time is called the rolling oil critical failure temperature Τ. If the local temperature of the deformation zone exceeds Τ, the boundary will rupture, leading to direct contact with the metal surface, which will increase the friction factor and wear, and the temperature of the deformation zone will also rise, which further promotes the rupture of the oil film. The percentage M of the area where the metal surface is in direct contact. It will increase rapidly, and the heat will accumulate rapidly in this place, causing the material surface at the outlet to become slab and bulge.
Process lubricating oil has different critical failure temperature T, and its temperature is related to the performance of lubricating base oil and the ratio of additives. The audible membrane formed by the additive molecules is stronger and can not break at higher temperatures, but the strength of the oil film and the critical failure temperature T formed by the additives of different proportions are different. The reasonable preparation of rolling oil is very important to enhance the strength of the oil film and increase the rolling speed. Generally, the preparation of rolling oil is based on the principles of high oil film strength, low viscosity, and low oil stain tendency. First, select the appropriate base oil and the appropriate proportion of additives, and at the same time, it should be adjusted according to the actual production conditions of each factory. Strictly control the various performance parameters of the rolling oil during the preparation process.
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