Stainless steel heat treatment part corrosion protection tool and method based on magnetic polishing

Abstract

The invention provides a stainless steel heat treatment part corrosion protection tool and method based on magnetic polishing. The method comprises the steps that an oxide skin of a stainless steel heat treatment part is removed through nitric acid; preparation before magnetic polishing; magnetically polishing the stainless steel heat-treated part; according to the method, the surface oxide layer of the stainless steel heat-treated part can be removed, the smoothness and surface quality of the stainless steel heat-treated part are improved, the corrosion resistance of the stainless steel heat-treated part is improved, and therefore the corrosion problem caused by welding seam oxidation is solved.

Description

Technical Field

[0001] The present application belongs to the field of aviation manufacturing technology, and in particular relates to a rust protection tool and method for stainless steel heat-treated parts based on magnetic polishing. Background Art

[0002] 0Cr18Ni9 stainless steel is easily oxidized by high temperature air during heat treatment. The oxidation of stainless steel during heat treatment causes changes in the alloy elements in the weld, mainly carburization and Cr element burnout, as well as segregation of impurities. At the same time, stainless steel develops thick black oxide scale after heat treatment. The uneven thickness of the oxide scale causes the surface of the underlying base metal to be rough, uneven, and pitted.

[0003] During subsequent use, the oxidized welds will continue to be oxidized by the air to form a thick oxide scale, causing corrosion of the stainless steel welds and affecting the use and appearance of the stainless steel parts.

[0004] In order to improve the surface quality and corrosion resistance of stainless steel after heat treatment, this application proposes a rust protection process for 0Cr18Ni9 stainless steel heat-treated parts based on magnetic polishing, which has good protection effect, wide applicability, and low cost, and solves the rust problem of stainless steel caused by oxidation during heat treatment. Summary of the invention

[0005] Purpose of the invention: The present invention provides a rust protection process for 0Cr18Ni9 stainless steel heat-treated parts based on magnetic polishing. The method can remove the surface oxide layer of stainless steel heat-treated parts, improve the smoothness and surface quality of stainless steel heat-treated parts, and improve the corrosion resistance of stainless steel heat-treated parts, thereby solving the rust problem caused by weld oxidation.

[0006] In a first aspect, the present application provides a method for corrosion protection of stainless steel heat-treated parts based on magnetic polishing, the method comprising:

[0007] Nitric acid removes oxide scale from stainless steel heat-treated parts;

[0008] Preparation before magnetic polishing;

[0009] Magnetic polishing of heat-treated stainless steel parts.

[0010] Preferably, the nitric acid removes oxide scale from heat-treated stainless steel parts, comprising:

[0011] The stainless steel heat-treated parts are placed in a chemical solution to chemically remove the stainless steel oxide scale.

[0012] Preferably, the chemical solution consists of nitric acid and metal oxides; wherein the concentration of nitric acid is 360 g / L, the control range is 300-400 g / L, and the control range of metal oxides is ≤5 g / L.

[0013] Preferably, the test piece passivation operation temperature is room temperature; the passivation time is 120 minutes; wherein the chemical solution is used to accelerate the formation of the passivation film of the stainless steel heat-treated parts and improve the corrosion resistance of the stainless steel parts.

[0014] Preferably, the preparation before magnetic polishing includes:

[0015] Before polishing, the polishing steel needle used for magnetic polishing has a diameter of 0.8 mm, a length of 12 mm, and a total weight of 2 kg.

[0016] Preferably, the polishing medium is a mixture of tap water, polishing agent and cleaning agent; wherein, tap water: polishing agent: cleaning agent = 50L: 500mL: 250mL.

[0017] Preferably, the magnetic polishing of the stainless steel heat-treated parts comprises:

[0018] Place the stainless steel heat-treated parts on a magnetic polishing medium;

[0019] Magnetic polishing uses a high-speed rotating magnetic field to guide the magnetic needle in the container to hit the workpiece at a high frequency in the polishing medium. The steel needle and the workpiece grind in all directions and at multiple angles to remove oxides on the weld surface and eliminate the rough, uneven and pitting defects of the stainless steel base metal surface, thereby achieving the effect of polishing the surface, improving the surface smoothness and surface quality of stainless steel heat-treated parts, thereby improving the corrosion resistance of stainless steel heat-treated parts.

[0020] In a second aspect, the present application also provides a rust protection tool for stainless steel heat-treated parts based on magnetic polishing, the tool comprising:

[0021] Polishing barrel;

[0022] Polishing liquid, arranged in the polishing barrel;

[0023] an annular polishing fixture, disposed in the polishing liquid;

[0024] The part to be polished is arranged on the annular polishing fixture.

[0025] Beneficial technical effects of this application:

[0026] The invention is simple, practical, easy to operate, does not increase the economic cost of parts processing, can remove the surface oxide layer of stainless steel heat-treated parts, eliminate the surface roughness, unevenness, pitting and other defects of the stainless steel base metal, improve the surface smoothness and surface quality of stainless steel heat-treated parts, thereby improving the corrosion resistance of stainless steel heat-treated parts. It has good protection effect, wide application range, and low cost, and solves the rust problem of stainless steel heat-treated parts caused by high-temperature oxidation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of a method for rust protection of stainless steel heat-treated parts based on magnetic polishing provided in an embodiment of the present application;

[0028] Figure 2 It is a structural schematic diagram of a rust protection tooling for stainless steel heat-treated parts based on magnetic polishing provided in an embodiment of the present application;

[0029] Among them, 1-polishing barrel, 2-polishing liquid, 3-annular polishing fixture, 4-parts to be polished. DETAILED DESCRIPTION

[0030] It should be noted that after heat treatment, stainless steel will have thick black oxide scale. The uneven thickness of the oxide scale causes the surface of the underlying base metal to be rough, uneven, and pitted. It is difficult to completely remove the oxide scale from the depressions and pits by only using magnetic polishing or mechanical grinding, resulting in a dark and dull surface of the parts after magnetic polishing.

[0031] However, pickling and passivation can completely remove the oxide scale on the surface depressions and pits, but the surface of the parts is rough after heat treatment, which is not conducive to the formation of passivation film. However, magnetic polishing after pickling and passivation can not only completely remove the thick oxide scale, but also make the stainless steel surface smooth, easy to quickly form a passivation film, avoid secondary oxidation rust, and thus improve the surface corrosion resistance of stainless steel parts.

[0032] The invention belongs to the engineering application of stainless steel weld corrosion protection in the field of aviation manufacturing, and relates to a corrosion protection process for 0Cr18Ni9 stainless steel heat-treated parts based on magnetic polishing.

[0033] The invention provides a corrosion protection process method for 0Cr18Ni9 stainless steel heat-treated parts based on magnetic polishing. The process flow comprises: removing stainless steel oxide scale with nitric acid, preparation before magnetic polishing, and magnetic polishing of stainless steel heat-treated parts.

[0034] The invention is simple, practical, easy to operate, does not increase the economic cost of parts processing, can remove the surface oxide layer of stainless steel heat-treated parts, eliminate the surface roughness, unevenness, pitting and other defects of the stainless steel base metal, improve the surface smoothness and surface quality of stainless steel heat-treated parts, thereby improving the corrosion resistance of stainless steel heat-treated parts. It has good protection effect, wide application range, and low cost, and solves the rust problem of stainless steel heat-treated parts caused by high-temperature oxidation.

[0035] See also Figure 1 and Figure 2 The present invention is implemented by the following technical solution, and the steps are as follows:

[0036] Step 1: Use nitric acid to remove the oxide scale from stainless steel.

[0037] Among them, the stainless steel heat-treated parts are placed in a chemical solution to remove the stainless steel oxide scale chemically. The chemical solution is composed of nitric acid and metal oxides, where the nitric acid concentration is 360g / L, the control range is 300-400g / L, and the metal oxide control range is ≤5g / L. The test piece passivation operating temperature: room temperature; passivation time: 120min. The chemical solution can accelerate the formation of the passivation film of stainless steel heat-treated parts and improve the corrosion resistance of stainless steel parts.

[0038] Step 2: Preparation before magnetic polishing.

[0039] Before polishing, the polishing steel needle used for magnetic polishing has a diameter of 0.8 mm and a length of 12 mm, and the total weight of the polishing needle is 2 kg. The polishing medium is a mixture of tap water, polishing agent and cleaning agent, and the ratio of tap water: polishing agent: cleaning agent = 50 L: 500 mL: 250 mL.

[0040] Step 3: Magnetic polishing of stainless steel heat-treated parts.

[0041] Among them, the stainless steel heat-treated parts are placed in the magnetic polishing medium. Magnetic polishing uses a high-speed rotating magnetic field to guide the magnetic needle in the container to hit the workpiece at high frequency in the polishing medium. The steel needle and the workpiece grind in all directions and angles to remove the oxide on the weld surface, eliminate the surface roughness, unevenness, pitting and other defects of the stainless steel base metal, achieve the effect of polishing the surface, improve the surface smoothness and surface quality of the stainless steel heat-treated parts, and thus improve the corrosion resistance of the stainless steel heat-treated parts.

[0042] The invention is simple, practical, easy to operate, does not increase the economic cost of parts processing, can remove the surface oxide layer of stainless steel heat-treated parts, eliminate the surface roughness, unevenness, pitting and other defects of the stainless steel base metal, improve the surface smoothness and surface quality of stainless steel heat-treated parts, thereby improving the corrosion resistance of stainless steel heat-treated parts. It has good protection effect, wide application range, and low cost, and solves the rust problem of stainless steel heat-treated parts caused by high-temperature oxidation.

Claims

1. A method for corrosion protection of stainless steel heat-treated parts based on magnetic polishing, characterized in that: The method comprises: Nitric acid removes oxide scale from stainless steel heat-treated parts; Preparation before magnetic polishing; Magnetic polishing of heat-treated stainless steel parts.

2. The method according to claim 1, characterized in that The nitric acid removes the oxide scale of the stainless steel heat-treated parts, including: The stainless steel heat-treated parts are placed in a chemical solution to chemically remove the stainless steel oxide scale.

3. The method according to claim 2, characterized in that The chemical solution consists of nitric acid and metal oxides; wherein the concentration of nitric acid is 360 g / L, the control range is 300-400 g / L, and the control range of metal oxides is ≤5 g / L.

4. The method according to claim 3, characterized in that Test piece passivation operation temperature: room temperature; passivation time: 120 minutes; the chemical solution is used to accelerate the formation of passivation film on stainless steel heat-treated parts and improve the corrosion resistance of stainless steel parts.

5. The method according to claim 1, characterized in that The preparation before magnetic polishing includes that before polishing, the polishing steel needle selected for magnetic polishing has a diameter of 0.8mm, a length of 12mm, and a total weight of 2Kg.

6. The method according to claim 5, characterized in that The polishing medium is a mixture of tap water, polishing agent and cleaning agent; wherein, tap water: polishing agent: cleaning agent = 50L: 500mL: 250mL.

7. The method according to claim 1, characterized in that The magnetic polishing of stainless steel heat-treated parts includes: Place the stainless steel heat-treated parts on a magnetic polishing medium; Magnetic polishing uses a high-speed rotating magnetic field to guide the magnetic needle in the container to hit the workpiece at a high frequency in the polishing medium. The steel needle and the workpiece grind in all directions and at multiple angles to remove oxides on the weld surface and eliminate the rough, uneven and pitting defects of the stainless steel base metal surface, thereby achieving the effect of polishing the surface, improving the surface smoothness and surface quality of stainless steel heat-treated parts, thereby improving the corrosion resistance of stainless steel heat-treated parts.

8. A rust protection tool for stainless steel heat-treated parts based on magnetic polishing, characterized in that: The tooling includes: Polishing barrel; Polishing liquid, arranged in the polishing barrel; an annular polishing fixture, disposed in the polishing liquid; The part to be polished is arranged on the annular polishing fixture.

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