| 45 steel tire mold is affected by rubber adhesion, corrosion, high frequency friction and others in the course of working process. It will make its organization and morphology failure because of different degrees of damage. This requires disassembling and cleaning even replacing the tire mold frequently, which will not only shorten the lifetime, but also increase the cost of production. Therefore, how to improve the anti adhesion and failure properties of the mold have important research value.In general, the structure of tire mold is complex, its size is large, its surface quality request strictly. If the mold is prepared by high-performance materials, it will make the production cost increased, its use scope also get narrowed. Material surface technology can satisfy the quality requirements of mold corrosion, adhesion, fatigue, wear-resistance and others, which can solve the all above problems with lowly cost and highly benefit. Therefore, this article proposes a method of anodic oxidation and electrochemical composite treatment, which is used to prepare the 45 steel surface multiscale micro nano composite structures coated with Zn-Sn alloy by controlling the related process parameters such as the reaction time, voltage, temperature, oxidants. Then, this paper will study on anti-adhesion and anti corrosion of the structures during the rubber vulcanized process. The main research contents of this paper are as follows:1. Using constant voltage anodic oxidation method, choosing test voltage as 40V, experimental electrolyte solution as 240ml (CH2OH)2+10ml H2O+0.3wt% NH4F, reaction temperature as 20 ℃, time as 10min,45 steel surface can obtain a random even-distributed and suborbicular nanometer pore structures. Its size is 20-150 nm, its depth is 1-5 μm. Researching the process parameters we can find:Increasing voltage, prolonging time, reducing the temperature and increasing deionized water, the formation of micro-nano structures on the surface are reduced, the shape is irregular, distributions are uneven. With the increasing of NH4+ concentration, nano structures have no obvious change. F- increased, the number of pore structures get decreased, its size get increased. Adding in oxidant, it can generate the coral pore structure. Putting in the reaming ion, the surface can form a single tubular structure.2. Using the electrochemical deposition method, choosing Zn2P2O7 and SnSO4 as electrolyte system, the micro-nano composite coated structure can be obtained after electrodepositing Zn-Sn alloy on the 45 steel micro-nano structure surface. Its size is 20-50 nm and its depth is 1-3 μm.3. Analyzing the properties of Zn-Sn alloy coated micro-nano composite structures through heat treatment, aging, wear-resistance and thermal shock resistance test. The results show that the properties of composite structures is good, the wear is less and adhesion is further improved after annealing and aging treatment.4. Flat vulcanized experiment:Simulating the vulcanized process of rubber tires, comparing the vulcanization adhesion and surface corrosion failure of original sample, anodized sample and sediment specimen, we find that Zn-Sn alloy coated micro-nano composite structures have protective effect on the matrix. It has foils effect on the rubber, which can alienate the rubber. This will make the accumulation of vulcanized fouling less than before, it also will make the fouling weight gain more slowly than the original mold. Furthermore, the structures also can reduce the failure possibility which have the friction reducing effect on highly frequency friction. It can be used to solve vulcanized problem of the tire mold. |
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