Method and device for vacuum hot dip aluminum or aluminum alloy plating for metal workpiece

Abstract

The invention discloses a method and a device for vacuum hot dip aluminum or aluminum alloy plating for a metal workpiece, which can effectively prolong the service life of the metal workpiece. The method comprises the following steps of: loading, vacuumizing for furnace sweeping, carrying out metal workpiece reduction, melting molten aluminum, carrying out hot dip aluminum or aluminum alloy plating, cooling the metal workpiece and taking out the metal workpiece. The device comprises a vacuum pump, a reversing valve, a reduction furnace exhaust pipe, a cooling furnace exhaust pipe, an inlet valve, a cooling water outlet, connection bolts, a winding motor, a steel wire rope, a feeding mechanism, a charging tray, an upper vent valve, a cooling furnace, a cooling wall, a cooling water inlet, a sealing valve cover, a driving rotation shaft, a reduction furnace, a heating element, a reduction furnace insulating layer, a lower vent valve, molten aluminum, an aluminum melting furnace, a heater and an molten aluminum melting furnace insulating layer. By the method and the device provided by the invention, the defect of plating omission can be removed, and the dip plating speed is increased; in the dip plating process, anti-oxidation treatment and degassing treatment can be carried out for the plating solution in vacuum condition, the defects, such as a pin hole and accretion, are eliminated, and the dip plating quality is improved.

Description

technical field [0001] The invention relates to the technical field of metal material surface coating, in particular to a method and a device for vacuum hot-dipping aluminum or aluminum alloy coating on a metal workpiece. Background technique [0002] Hot-dip aluminum or aluminum alloy coating on the surface of metal workpieces is one of the effective ways to prevent corrosion and prolong the service life of metal workpieces. At present, there are many methods for hot-dip aluminum or aluminum alloy coating, but there are two main methods: gas protection method and solvent method. kind. Patent documents CN1020928C, AU696077B1, EP0698671A1, EP0467749A1, KR2007 / 006720, etc. have provided the technology of continuous hot-dip aluminum and aluminum alloy plating by gas protection method, but this method is only suitable for large-scale continuous production of a single product, such as Sendzimir method, improved Sendzimir Such methods require large equipment investment, high proc...

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Problems solved by technology

Patent documents CN1020928C, AU696077B1, EP0698671A1, EP0467749A1, KR2007 / 006720, etc. have provided the technology of continuous hot-dip aluminum and aluminum alloy plating by gas protection method, but this method is only suitable for large-scale continuous production of a single product, such as Sendzimir method, improved Sendzimir method, United States Steel Association method, etc. These methods require large investment in equipment, high process requirements, cannot stop production at any time, and are difficult to produce

On the contrary, patent documents CN1243121C, CN1069703C, CN1381607A, etc. have provided the process of solvent method hot-dip aluminum plating and aluminum alloy. This type of method has relatively low equipment investment, low process requirements, and flexible products. And aluminum alloys still have a series of problems, such as: (1) Pickling and fluxing must be carried out before plating, the flux is expensive, and fluorine salts are toxic, which not only increases the cost of immersion plating, but also pollutes the environment; (2 ) The salt film of the plating flux is easy to absorb moisture, and it must be fully dried before plating, otherwise it will easily cause missing plating and pinholes, which will affect the surface quality and corrosion resistance; (3) The surface of the plating solution must be covered with molten salt, which is easy to age and volatilize. Damage to the health of personnel; (4) Molten salt adheres to the surface of the workpiece after plating, making cleaning more difficult, increasing costs, and polluting the environment

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