A kind of metal casting surface passivation method

Abstract

The invention discloses a metal casting surface passivating method. According to the method, a metal casting passivating assembly and a passivating agent recycling assembly are adopted; the metal casting passivating assembly comprises a reaction tank which is used for a passivating reaction; an outlet of the reaction tank is connected with a buffering tank of the passivating agent recycling assembly; the buffering tank is connected with a recycling tank after filtering out impurities which are contained in a low-concentration passivating agent; the recycling tank is connected with a second material storage barrel which stores a high-concentration passivating agent, and is used for neutralizing the low-concentration passivating agent into an available passivating agent with relatively high concentration; the available passivating agent is stored in a first material storage barrel for the reaction tank for use. The buffering tank and the recycling tank are arranged for treating the low-concentration passivating agent discharged from the reaction tank so as to recover the low-concentration passivating agent to a concentration which can be used for the passivating reaction; the cost is reduced, and the environment pollution caused by direct discharging is avoided.

Description

technical field [0001] The invention relates to the field of metal casting production devices, in particular to a passivation method for the surface of metal castings. Background technique [0002] Passivation is a method to transform the metal surface into a state that is not easily oxidized, and to delay the corrosion rate of the metal. What the existing passivation method adopts is to throw metal castings in the reaction pool that is filled with passivation agent, the defect of this passivation method is: [0003] 1. Since the passivation reaction will consume the active ingredients in the passivating agent, the thickness of the surface passivation of metal castings put into the reaction pool in different batches before and after will be different, which will affect the product quality. [0004] 2. Since the passivation reaction uses an excessive amount of passivating agent in the reaction pool, these passivating agents will produce a large number of low-concentration pa...

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Problems solved by technology

[0003] 1. Since the passivation reaction will consume the active ingredients in the passivation agent, the thickness of the surface passivation of metal castings put into the reaction pool in different batches before and after will be different, which will affect the product quality

[0004] 2. Since the passivation reaction uses an excessive amount of passivating agent in the reaction pool, these passivating agents will produce a large number of low-concentration passivating agent residues after the passivating reaction is completed. If they are processed or recycled, then The cost is high; if it is discharged directly, it will seriously pollute the environment

[0005] 3. Due to the high oxidation and corrosiveness of the passivating agent, the liquid level switch used to detect the liquid level of the passivating agent is easily damaged after long-term contact with the passivating agent, resulting in high maintenance costs

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