CN104762632A - Aluminum alloy forging surface cleaning method - Google Patents

Abstract

The invention discloses an aluminum alloy forging surface cleaning method. According to the method, an aluminum alloy forging containing carbon particles on the surface is cleaned in the following steps of primary acid pickling, primary alkali washing, brightening, soaking in cutting liquid, secondary alkali washing, secondary acid pickling, soaking in water and drying. In the technology, soaking in the cutting liquid is needed so that the settlement speed of the carbon particles can be increased, and work efficiency is improved. Meanwhile, a compact lubricating film can be formed on the surface of the aluminum alloy forging to prevent the surface from being oxidized. Mixed acid of nitric acid and phosphoric acid is selected in the primary acid pickling, so that the smoothness of the surface of the cleaned aluminum alloy forging is good, and the dirt removing capacity is strong. The technology improves production efficiency, reduces production cost, and is easy and mature in operation and suitable for large-scale application and popularization.

Description

Surface cleaning method of aluminum alloy forgings

technical field

The invention relates to the technical field of cleaning aluminum alloy forgings, in particular to a surface cleaning method for aluminum alloy forgings.

Background technique

With the increasingly prominent problems of energy shortage and environmental pollution, energy conservation and emission reduction have become the inherent requirements of economic and social development. Correspondingly, the demand for weight reduction in the transportation industry, especially automobiles, has become increasingly urgent, and a large number of aluminum alloy parts have been valued and applied. Aluminum alloy parts with special requirements need to be forged, which can not only reduce their own weight but also achieve higher strength. During the metal forging process, lubricants need to be sprayed on the inner wall of the forging mold cavity to reduce the friction coefficient and prevent the metal from sticking to the mold during the forging process. Oil-based graphite lubricants are mainly used in the forging process of aluminum alloys. This lubricant is mainly composed of lubricating oil and graphite, so that it can achieve a better lubrication effect while demoulding smoothly and prevent the oxidation of forgings. However, there is a difficult problem in the use of oil-based graphite lubricants, that is, the carbon particles formed by the vaporization of graphite at high temperature are easy to adhere to the surface of aluminum alloy forgings, and the oil on the forging equipment is easy to form a dense black oil film. . The traditional steel brush or shot blasting cleaning of the metal surface is easy to damage the surface of the forging for softer aluminum alloys, and will also embed graphite particles on the surface of the forging, which is even more difficult to clean. Therefore, the cleaning of surface particles of aluminum alloy forgings is one of the key issues restricting product development.

In the prior art, there are methods for removing surface stains by using processes such as alkali washing, pickling, and hot water immersion, which are likely to cause corrosion on the surface of the aluminum alloy, resulting in poor gloss on the aluminum alloy surface, or incomplete cleaning and removal of particles. .

In view of this, it is necessary to develop a cleaning method that can completely remove the particles on the surface of aluminum alloy forgings without further corroding the surface of aluminum alloy, and can restore the original color of aluminum alloy after washing.

Contents of the invention

The invention proposes a method for cleaning the surface of an aluminum alloy forging, which solves the problems of incomplete removal of particles on the aluminum alloy surface, corrosion of the aluminum alloy surface, and poor gloss after washing in the prior art.

Technical scheme of the present invention is realized like this:

A method for cleaning the surface of an aluminum alloy forging, comprising:

The aluminum alloy forgings containing carbon particles on the surface are cleaned in the following steps;

first pickling;

the first alkaline wash;

bright;

Soak in cutting fluid;

Second alkaline washing;

second pickling;

soaking in water; and

dry.

As a preferred technical solution, the cutting fluid is an aluminum alloy cutting fluid, and any commercially available aluminum alloy cutting fluid can be used in the cleaning process of the present invention. In the present invention, the aluminum alloy cutting fluid is used to soak the aluminum alloy forging, so that the carbon particles on the surface of the aluminum alloy forging can be quickly settled, and at the same time, a dense lubricating film is produced on the surface of the aluminum alloy forging to prevent surface oxidation; therefore, this step is rust-proof and clean. key step. However, the cleaning of the prior art does not contain this step, but is directly soaked in pure water, so that the carbon particles on the surface of the aluminum alloy forgings settle slowly and take a long time, and it is difficult to form a protective lubricating film. Therefore, the process of using cutting fluid immersion has high efficiency, anti-rust and better cleaning effect compared with the prior art.

As a preferred technical solution, the first pickling process is as follows: use a mixed acid of phosphoric acid solution with a mass percentage concentration of 40-60% and a nitric acid solution with a mass percentage concentration of 5-10% to clean the aluminum alloy forging, and control the temperature At 80-110° C., it is enough to wash until the carbon particles are exposed on the surface of the aluminum alloy forging. In this process, if a single acid is used for cleaning or a mixed acid is used for cleaning, the surface finish of the aluminum alloy forging after cleaning is generally not good. The cleaning time of this process is generally 3-5 minutes, as long as the exposed carbon particles on the surface of the aluminum alloy forging can be seen. The pickling in this step has two functions, one is to remove the oil stain on the surface of the aluminum alloy forging, and the other is to expose the carbon particles on the surface of the aluminum alloy forging.

As a preferred technical solution, the volume ratio of the phosphoric acid solution to the nitric acid solution is 1:1.

As a preferred technical solution, the first alkali cleaning process is as follows: the aluminum alloy forging after the first pickling is cleaned with a NaOH solution with a mass percentage concentration of 8-12%, the temperature is controlled at 50-70°C, and the time is It is 0.5-2min. The function of this step is to neutralize the pH value of the surface of the aluminum alloy forging to prevent further corrosion of the aluminum alloy forging.

As a preferred technical solution, the brightening process is as follows: soak the aluminum alloy forging after the first alkali washing with a nitric acid solution with a concentration of 20-30% by mass for 1-2 minutes. The function of this step is to further neutralize the alkalinity of the first alkaline washing.

As a preferred technical solution, the second alkali cleaning process is as follows: use NaOH solution with a concentration of 6-8% by mass to clean the aluminum alloy forging after soaking in cutting fluid, control the temperature at 20-40°C, and the time is 4-5min. The function of this step is to degrease and wash away oil stains.

As a preferred technical solution, the second pickling process is as follows: use nitric acid solution with a mass percentage concentration of 4-6% to clean the aluminum alloy forgings after the second alkali washing, and control the temperature at 30-50°C. 4-5min. The function of this step is to neutralize the alkalinity of the second alkaline wash.

As a preferred technical solution, the drying is air drying.

Compared with the prior art, the present invention has the following beneficial effects: the process of the present invention needs to be soaked in cutting fluid, which can accelerate the sedimentation velocity of carbon particles, improve work efficiency, and at the same time form dense A lubricating film prevents surface oxidation.

(1) In the process, the mixed acid of nitric acid and phosphoric acid is selected in the first pickling, so that the surface finish of the aluminum alloy forging after washing is better, and the ability to remove oil stains is also strong.

(2) The process improves production efficiency, reduces production cost, and is simple and mature in operation, which is suitable for large-scale popularization and application.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The invention utilizes the amphoteric characteristics of aluminum alloy forgings, that is, it will corrode when encountering acid and alkali, while graphite is acid-resistant and alkali-resistant, and corrodes a thin layer of metal in aluminum alloy forgings to expose and separate carbon particles. Based on this, the invention provides a method for cleaning the surface of an alloy forging. Wherein the selection of the type of acid for the first pickling and the cutting fluid immersion process are key points of the present invention. The cutting fluid can be the aluminum alloy cutting fluid sold in the market, and there are no other special requirements. The specific usage method will be described in detail below. The materials used in the following examples are all commercially available products.

Example 1

A method for cleaning the surface of an aluminum alloy forging, comprising:

The aluminum alloy forgings containing carbon particles on the surface are cleaned in the following steps;

Step S1: first pickling;

Preparation of mixed acid: get 0.5L of phosphoric acid solution with mass percentage concentration of 40%, get 0.5L of nitric acid solution with mass percentage concentration of 10%, mix phosphoric acid solution and nitric acid solution to obtain mixed acid (the volume of solution is related to the quantity of cleaning workpieces) , the cleaning of individual workpieces is only advisable to submerge the workpieces, if it is cleaned in large quantities, then an appropriate volume of a certain percentage concentration solution needs to be taken, the solution volume of the present embodiment is an example with 1L);

Use the mixed acid prepared above to clean the aluminum alloy forgings. During the cleaning process, the temperature is controlled at about 80°C, and the cleaning is performed for about 3 minutes until the carbon particles are exposed on the surface of the aluminum alloy forgings, and then the next step of cleaning is performed. In this process, if a single acid is used for cleaning or a mixed acid is used for cleaning, the surface finish of the aluminum alloy forging after cleaning is generally not good. The pickling in this step has two functions, one is to remove the oil stain on the surface of the aluminum alloy forging, and the other is to expose the carbon particles on the surface of the aluminum alloy forging.

Step S2: the first alkali washing; the function of this step is to neutralize the pH value of the surface of the aluminum alloy forging and prevent further corrosion of the aluminum alloy forging.

Use 1 L of NaOH solution with a concentration of 8% by mass to clean the aluminum alloy forging after the first pickling, the temperature is controlled at about 50° C., and the time is about 0.5 min.

Step S3: brightening; the function of this step is to further neutralize the alkalinity of the first alkaline washing.

Using 1L of nitric acid solution with a concentration of 20% by mass, the aluminum alloy forging after the first alkali cleaning is soaked in the nitric acid solution for about 2 minutes.

Step S4: soaking in cutting fluid;

Soak the aluminum alloy forgings after the brightening process in the aluminum alloy cutting fluid, usually for 2-3 days, the carbon particles on the surface of the soaked aluminum alloy forgings settle quickly, and at the same time produce dense The lubricating film prevents surface oxidation; this step is therefore a critical step in rust prevention as well as cleaning. However, the cleaning of the prior art does not contain this step, but is directly soaked in pure water, so that the carbon particles on the surface of the aluminum alloy forgings settle slowly and take a long time, and it is difficult to form a protective lubricating film. Therefore, the process of using cutting fluid immersion has high efficiency, anti-rust and better cleaning effect compared with the prior art.

Step S5: second alkali washing; the function of this step is to degrease and wash away oil stains.

Use 1L of NaOH solution with a mass percentage concentration of 6% to clean the aluminum alloy forgings soaked in cutting fluid. The temperature is controlled at 20°C during the whole process, and the time is about 4 minutes.

Step S6: second pickling; the function of this step is to neutralize the alkalinity of the second alkali washing.

The aluminum alloy forging after the second alkali washing is cleaned with a nitric acid solution with a concentration of 4% by mass, and the temperature during the cleaning process is controlled at about 30° C. for about 4 minutes.

Step S7: soaking in water;

Soak the aluminum alloy forgings treated in step S6 in pure water for 2-3 days. The purpose of soaking is to clean the aluminum alloy forgings after acid-base neutralization, and to quantitatively detect the residual amount of carbon particles in the water tank. , this time can be shortened during mass production.

Step S8: air-dry the water marks on the aluminum alloy forging after soaking in step S7.

The surface of the aluminum alloy forging after the treatment of S1-8 has almost no particle residue, and the oil stain removal effect is good, there is no water mark, and the surface of the aluminum alloy forging is bright as the original color of aluminum alloy.

Example 2

A method for cleaning the surface of an aluminum alloy forging, comprising:

The aluminum alloy forgings containing carbon particles on the surface are cleaned in the following steps;

Step S1: first pickling;

Preparation of mixed acid: take 0.5L of phosphoric acid solution with a mass percentage concentration of 60%, take 0.5L of a nitric acid solution with a mass percentage concentration of 10%, mix the phosphoric acid solution and the nitric acid solution to obtain a mixed acid;

Use the mixed acid prepared above to clean the aluminum alloy forgings. During the cleaning process, the temperature is controlled at about 100°C, and the cleaning is performed for about 5 minutes until the carbon particles are exposed on the surface of the aluminum alloy forgings, and then the next step of cleaning is performed. In this process, if a single acid is used for cleaning or a mixed acid is used for cleaning, the surface finish of the aluminum alloy forging after cleaning is generally not good. The pickling in this step has two functions, one is to remove the oil stain on the surface of the aluminum alloy forging, and the other is to expose the carbon particles on the surface of the aluminum alloy forging.

Step S2: the first alkali washing; the function of this step is to neutralize the pH value of the surface of the aluminum alloy forging and prevent further corrosion of the aluminum alloy forging.

Use 1L of NaOH solution with a concentration of 10% by mass to clean the aluminum alloy forging after the first pickling, the temperature is controlled at about 60° C., and the time is about 1.0 min.

Step S3: brightening; the function of this step is to further neutralize the alkalinity of the first alkaline washing.

Using 1 L of nitric acid solution with a concentration of 25% by mass, the aluminum alloy forging after the first alkali cleaning is soaked in the nitric acid solution for about 1 min.

Step S4: soaking in cutting fluid;

Soak the aluminum alloy forgings after the brightening process in the aluminum alloy cutting fluid, usually for 2-3 days, the carbon particles on the surface of the soaked aluminum alloy forgings settle quickly, and at the same time produce dense The lubricating film prevents surface oxidation; this step is therefore a critical step in rust prevention as well as cleaning. However, the cleaning of the prior art does not contain this step, but is directly soaked in pure water, so that the carbon particles on the surface of the aluminum alloy forgings settle slowly and take a long time, and it is difficult to form a protective lubricating film. Therefore, the process of using cutting fluid immersion has high efficiency, anti-rust and better cleaning effect compared with the prior art.

Step S5: second alkali washing; the function of this step is to degrease and wash away oil stains.

Use 1L of NaOH solution with a mass percentage concentration of 7% to clean the aluminum alloy forgings soaked in cutting fluid. During the whole process, the temperature is controlled at 30°C and the time is about 4 minutes.

Step S6: second pickling; the function of this step is to neutralize the alkalinity of the second alkali washing.

The aluminum alloy forging after the second alkali washing is cleaned with a nitric acid solution with a concentration of 5% by mass, and the temperature during the cleaning process is controlled at about 40° C. for about 5 minutes.

Step S7: soaking in water;

Soak the aluminum alloy forgings treated in step S6 in pure water for 2-3 days. The purpose of soaking is to clean the aluminum alloy forgings after acid-base neutralization, and to quantitatively detect the residual amount of carbon particles in the water tank. , this time can be shortened during mass production.

Step S8: air-dry the water marks on the aluminum alloy forging after soaking in step S7.

Example 3

A method for cleaning the surface of an aluminum alloy forging, comprising:

The aluminum alloy forgings containing carbon particles on the surface are cleaned in the following steps;

Step S1: first pickling;

Preparation of mixed acid: take 0.5L of phosphoric acid solution with a mass percentage concentration of 50%, take 0.5L of a nitric acid solution with a mass percentage concentration of 5%, mix the phosphoric acid solution and the nitric acid solution to obtain a mixed acid;

Use the mixed acid prepared above to clean the aluminum alloy forgings. During the cleaning process, the temperature is controlled at about 110°C, and the cleaning is performed for about 5 minutes until the carbon particles are exposed on the surface of the aluminum alloy forgings, and then the next step of cleaning is performed. In this process, if a single acid is used for cleaning or a mixed acid is used for cleaning, the surface finish of the aluminum alloy forging after cleaning is generally not good. The pickling in this step has two functions, one is to remove the oil stain on the surface of the aluminum alloy forging, and the other is to expose the carbon particles on the surface of the aluminum alloy forging.

Step S2: the first alkali washing; the function of this step is to neutralize the pH value of the surface of the aluminum alloy forging and prevent further corrosion of the aluminum alloy forging.

Use 1L of NaOH solution with a concentration of 12% by mass to clean the aluminum alloy forging after the first pickling, the temperature is controlled at about 70° C., and the time is about 2.0 min.

Step S3: brightening; the function of this step is to further neutralize the alkalinity of the first alkaline washing.

Using 1 L of nitric acid solution with a concentration of 30% by mass, the aluminum alloy forgings after the first alkali cleaning are soaked in the nitric acid solution for about 1 min.

Step S4: soaking in cutting fluid;

Soak the aluminum alloy forgings after the brightening process in the aluminum alloy cutting fluid, usually for 2-3 days, the carbon particles on the surface of the soaked aluminum alloy forgings settle quickly, and at the same time produce dense The lubricating film prevents surface oxidation; this step is therefore a critical step in rust prevention as well as cleaning. However, the cleaning of the prior art does not contain this step, but is directly soaked in pure water, so that the carbon particles on the surface of the aluminum alloy forgings settle slowly and take a long time, and it is difficult to form a protective lubricating film. Therefore, the process of using cutting fluid immersion has high efficiency, anti-rust and better cleaning effect compared with the prior art.

Step S5: second alkali washing; the function of this step is to degrease and wash away oil stains.

Use 1L of NaOH solution with a mass percentage concentration of 8% to clean the aluminum alloy forgings soaked in cutting fluid. During the whole process, the temperature is controlled at 40 ° C and the time is about 4 minutes.

Step S6: second pickling; the function of this step is to neutralize the alkalinity of the second alkali washing.

The aluminum alloy forging after the second alkali washing is cleaned with a nitric acid solution with a concentration of 6% by mass, and the temperature during the cleaning process is controlled at about 50° C. for about 4 minutes.

Step S7: soaking in water;

Soak the aluminum alloy forgings treated in step S6 in pure water for 2-3 days. The purpose of soaking is to clean the aluminum alloy forgings after acid-base neutralization, and to quantitatively detect the residual amount of carbon particles in the water tank. , this time can be shortened during mass production.

Step S8: air-dry the water marks on the aluminum alloy forging after soaking in step S7.

The surface of the aluminum alloy forging after the treatment of S1-8 has almost no particle residue, and the oil stain removal effect is good, there is no water mark, and the surface of the aluminum alloy forging is bright as the original color of aluminum alloy.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. A surface cleaning method for an aluminum alloy forging, characterized in that it comprises: The aluminum alloy forgings containing carbon particles on the surface are cleaned in the following steps; first pickling; the first alkaline washing; bright; Soak in cutting fluid; Second alkaline washing; Second pickling; soaking in water; and dry. 2. The method for cleaning the surface of an aluminum alloy forging according to claim 1, wherein the cutting fluid is an aluminum alloy cutting fluid. 3. The method for cleaning the surface of an aluminum alloy forging according to claim 1, wherein the first pickling process is as follows: a phosphoric acid solution with a mass percentage concentration of 40-60% and a mass percentage concentration of 5- The aluminum alloy forging is cleaned with a mixed acid of 10% nitric acid solution, and the temperature is controlled at 80-110° C., until carbon particles are exposed on the surface of the aluminum alloy forging. 4. The method for cleaning the surface of an aluminum alloy forging according to claim 3, wherein the cleaning time is 3-5 minutes. 5. The method for cleaning the surface of an aluminum alloy forging according to claim 3 or 4, wherein the volume ratio of the phosphoric acid solution to the nitric acid solution is 1-1. 6. The method for cleaning the surface of an aluminum alloy forging according to claim 1, wherein the process of the first alkaline cleaning is as follows: use NaOH solution with a mass percentage concentration of 8-12% to clean the surface and then undergo the first acid cleaning For the aluminum alloy forging, the temperature is controlled at 50-70°C, and the time is 0.5-2min. 7. The method for cleaning the surface of an aluminum alloy forging according to claim 1, wherein the brightening process is as follows: use a nitric acid solution with a mass percent concentration of 20-30% to soak the forging after the first alkali cleaning For the aluminum alloy forging, the soaking time is 1-2 minutes. 8. The method for cleaning the surface of an aluminum alloy forging according to claim 1, wherein the second alkaline cleaning process is as follows: use a NaOH solution with a mass percentage concentration of 6-8% to clean the polished surface. For the aluminum alloy forging, the temperature is controlled at 20-40° C., and the time is 4-5 minutes. 9. The method for cleaning the surface of an aluminum alloy forging according to claim 1, characterized in that the second pickling process is as follows: use nitric acid solution with a mass percentage concentration of 4-6% for cleaning and then the second alkaline cleaning For the aluminum alloy forging, the temperature is controlled at 30-50° C. for 4-5 minutes. 10. The method for cleaning the surface of an aluminum alloy forging according to claim 1, wherein the drying is air drying.