阅读说明：本技术 一种与涂层高附着的不锈钢表面处理方法 (Surface treatment method for stainless steel with high adhesion with coating ) 是由 刘景榕 牛建民 禹文娟 黄如祎 朱亦希 蒋荣勤 于 2020-08-04 设计创作，主要内容包括：本发明提供了一种与涂层高附着的不锈钢表面处理方法,包括以下步骤：(1)通过酸洗去除不锈钢表面的钝化膜,(2)采用非金属磨料在所述不锈钢表面进行喷砂,达到Sa2～Sa2.5等级；(3)采用阴极微电流抑制所述不锈钢表面的钝化；(4)涂覆涂层,(5)采用微电流使所述不锈钢未涂覆侧形成钝化层。本发明提高了不锈钢与涂层之间的结合强度；通过本方法进行表面处理后的不锈钢表面涂层附着力最高能达到7MPa,得到了显著提升。(The invention provides a stainless steel surface treatment method with high adhesion with a coating, which comprises the following steps: (1) removing a passive film on the surface of the stainless steel by acid washing, (2) carrying out sand blasting on the surface of the stainless steel by adopting a non-metallic abrasive material to reach the grade of Sa 2-Sa2.5; (3) inhibiting the passivation of the stainless steel surface by adopting cathode micro-current; (4) coating a coating, and (5) forming a passivation layer on the non-coating side of the stainless steel by using micro-current. The invention improves the bonding strength between the stainless steel and the coating; the adhesive force of the surface coating of the stainless steel subjected to surface treatment by the method can reach 7MPa at most, and is remarkably improved.)

1. A surface treatment method of stainless steel with high adhesion with a coating is characterized by comprising the following steps: (1) removing a passive film on the surface of the stainless steel by acid washing, (2) carrying out sand blasting on the surface of the stainless steel by adopting a non-metallic abrasive material to reach the grade of Sa 2-Sa2.5; (3) inhibiting the passivation of the stainless steel surface by adopting cathode micro-current; (4) coating a coating, and (5) forming a passivation layer on the non-coating side of the stainless steel by using micro-current.

2. The method for treating the surface of stainless steel according to claim 1, wherein in the step (1), the pickling solution for pickling is a mixture of one or more of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and the concentration of the pickling solution is 15 to 95%.

3. The stainless steel surface treatment method according to claim 1, wherein in the step (2), the non-metal abrasive is one or more of cross stone, garnet, olivine and brown corundum, and the pressure of the sand blasting is 0.4-0.8 MPa.

4. The stainless steel surface treatment method according to claim 1, wherein in the step (3), the voltage of the cathode micro-current is 0.8-1.2V relative to the saturated calomel electrode, the current is 0.01-0.5A, and the time for inhibiting passivation by the micro-current is 5-30 min.

5. The stainless steel surface treatment method according to claim 1, wherein in the step (4), the coating is performed by coating a primer on the stainless steel surface by one or more of spraying, brushing, rolling and dipping.

6. The stainless steel surface treatment method according to claim 1, wherein in the step (5), the voltage of the micro-current is-0.8V to-1.2V relative to a saturated calomel electrode, the current is 0.01 to 0.5A, and the passivation time of the micro-current is 5 to 30 min.

Technical Field

The invention belongs to the technical field of stainless steel surface treatment, and particularly relates to a stainless steel surface treatment method with high adhesion to a coating.

Background

The surface of stainless steel is easy to form a passive film, which can protect the stainless steel from corrosion, but the passive film of the stainless steel can influence the conventional surface treatment effect, and the common sand blasting is often insufficient in roughness, so that the adhesion of a paint film is poor, and the service safety is influenced. When the marine stainless steel is used in a crude oil tank and other parts, one side of the marine stainless steel is in crude oil and does not need to be coated, the other side of the marine stainless steel is used as a ballast tank and directly contacts with a seawater environment, and chloride ions in the seawater can damage a passive film of the stainless steel to cause pitting and perforation, so that the stainless steel on the side needs to be subjected to anticorrosive coating operation.

The document search of the prior art finds that Chinese patent documents CN 111001989A, CN 111002162A and CN 110976252A both provide surface treatment process methods of stainless steel materials, but the methods aim to improve the performances of the stainless steel materials such as welding, processing and the like, and do not relate to treatment measures for corrosion protection in a seawater environment.

Disclosure of Invention

The invention aims to provide a stainless steel surface treatment method with high adhesion with a coating, so as to overcome the problem that the corrosion protection treatment of stainless steel in a seawater environment is not involved in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the invention discloses a stainless steel surface treatment method with high adhesion with a coating, which is characterized by comprising the following steps of: (1) removing a passive film on the surface of the stainless steel by acid washing, (2) carrying out sand blasting on the surface of the stainless steel by adopting a non-metallic abrasive material to reach the grade of Sa 2-Sa2.5; (3) inhibiting the passivation of the stainless steel surface by adopting cathode micro-current; (4) coating a coating layer, (5) forming a passivation layer on the non-coating side of the stainless steel by using micro-current;

in the step (1), the pickling solution for pickling is one or a mixture of more of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and the concentration of the pickling solution is 15-95%;

in the step (2), the non-metal abrasive is one or more of cross stone, garnet, olivine and brown corundum, and the pressure of sand blasting is 0.4-0.8 MPa;

in the step (3), the voltage of the cathode micro-current is 0.8-1.2V relative to the saturated calomel electrode, the current is 0.01-0.5A, and the micro-current inhibition and passivation time is 5-30 min;

in the step (4), the coating layer is formed by coating a primer on the surface of the stainless steel in a manner of one or more than two of spraying, brushing, roller coating and dipping;

in the step (5), an external micro-current is adopted to accelerate the reaction of the surface of the stainless steel and oxygen to form a passivation layer, the voltage of the micro-current is-0.8V to-1.2V relative to the saturated calomel electrode, the current is 0.01 to 0.5A, and the passivation time of the micro-current is 5 to 30 min.

The invention has the beneficial effects that:

the invention adopts the acid cleaning, sand blasting and micro-current with opposite applied voltage to carry out surface treatment on the stainless steel, thereby improving the bonding strength between the stainless steel and the coating; the coating adhesive force of the conventional stainless steel surface can only reach 4MPa, and the adhesive force of the coating of the stainless steel surface after surface treatment by the method can reach 7MPa at most, so that the adhesive force is remarkably improved.

Detailed Description

It should be understood by those skilled in the art that the present embodiment is only for illustrating the present invention and is not to be used as a limitation of the present invention, and changes and modifications of the embodiment can be made within the scope of the claims of the present invention.

Example 1

(1) Cleaning the surface of the stainless steel by using phosphoric acid with the concentration of 60 percent, and removing oil stains and an oxidation film on the surface; (2) applying a voltage of 0.8V and a current of 0.1A to the stainless steel plate for 10 minutes, and inhibiting the surface of the stainless steel plate from generating a passive film in the air by using cathode micro-current; (3) performing sand blasting treatment on the surface of the stainless steel by using the cross stone, wherein the sand blasting pressure is 0.6Mpa and reaches the grade of Sa 2; (4) spraying epoxy zinc-rich paint with the thickness of 300 microns on the surface of the stainless steel under the pressure of 0.5 Mpa; (5) after the coating is dried, applying a voltage of-0.8V and a current of 30mA to the stainless steel for 5 minutes to accelerate the reaction of the uncoated side surface of the stainless steel with oxygen to form a passivation layer; thus obtaining the stainless steel with high adhesion with the coating.

The method specified by the GB/T5210 standard is adopted to test the adhesive force of the stainless steel surface coating to be 6Mpa, thereby meeting the requirements.

Example 2

(1) Cleaning the surface of the stainless steel by using nitric acid with the concentration of 70 percent to remove oil stains and oxidation films on the surface; (2) applying a voltage of 0.9V and a current of 0.2A to the stainless steel plate for 5 minutes, and inhibiting the surface of the stainless steel plate from generating a passive film in the air by using cathode micro-current; (3) carrying out sand blasting treatment on the surface of the stainless steel by using olivine, wherein the sand blasting pressure is 0.4Mpa and reaches the grade Sa2.5; (4) spraying the stainless steel surface with air pressure of 0.4Mpa, and spraying epoxy micaceous iron coating with thickness of 300 μm; (5) after the coating is dried, applying a voltage of-0.9V and a current of 20mA to the stainless steel for 10 minutes to accelerate the reaction of the uncoated side surface of the stainless steel with oxygen to form a passivation layer; thus obtaining the stainless steel with high adhesion with the coating.

The adhesion force of the stainless steel surface coating is tested to be 7Mpa by adopting a method specified by the GB/T5210 standard, and the requirement is met.

Example 3

(1) Cleaning the surface of the stainless steel by using hydrochloric acid with the concentration of 35 percent to remove oil stains and oxidation films on the surface; (2) applying 1V voltage and 0.3A current to the stainless steel plate for 7 minutes, and inhibiting the surface of the stainless steel from generating a passive film in the air by using cathode micro-current; (3) carrying out sand blasting treatment on the surface of the stainless steel by using garnet, wherein the sand blasting pressure is 0.8Mpa and reaches the grade Sa2.5; (4) spraying epoxy zinc-rich paint with the thickness of 300 microns on the surface of the stainless steel under the pressure of 0.3 Mpa; (5) after the coating is dried, applying a voltage of-1.0V and a current of 50mA to the stainless steel for 8 minutes to accelerate the reaction of the uncoated side surface of the stainless steel with oxygen to form a passivation layer; thus obtaining the stainless steel with high adhesion with the coating.

The method specified by the GB/T5210 standard is adopted to test the adhesive force of the stainless steel surface coating to be 6Mpa, thereby meeting the requirements.

Comparative example 1

Carrying out sand blasting treatment on the surface of the stainless steel by using garnet, wherein the sand blasting pressure is 0.8Mpa and reaches the grade Sa2.5; spraying epoxy zinc-rich paint with the thickness of 300 microns on the surface of the stainless steel under the pressure of 0.3 Mpa; the coated stainless steel is obtained.

The adhesive force of the surface coating of the stainless steel is tested to be 4Mpa by adopting a method specified by the GB/T5210 standard.