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Method for removing deteriorated layer on stainless steel surface

A surface metamorphic layer and stainless steel technology, applied in the field of polishing, can solve the problems of uneven brightness, damage to the surface flatness and precision of parts, and the inability to guarantee the flatness of parts, etc., and achieve the effect of good surface finish and bright color

Active Publication Date: 2022-03-25
西安赛隆增材技术股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, after the pure ammonium sulfate solution is ionized, due to the ionization and gasification of water molecules in the later stage of polishing, the ion concentration increases in the later stage of polishing, the electric field strength between the two electrodes decreases, and the chemical pitting behavior of the base metal is more serious. A longer polishing time will affect the smoothness of the part surface. Accuracy and accuracy are compromised
After hot isostatic pressing of 316L stainless steel parts, the composition of the metamorphic oxide layer on the surface is complex. After high temperature and high pressure, the bonding force between the interface of the metamorphic layer and the substrate is strong, and the low-concentration salt solution cannot achieve simultaneous plasma removal and electrolytic etching at the beginning of polishing. , the removal of the metamorphic layer is insufficient; and the chemical erosion of the metamorphic layer on the surface of the part by the pure ammonium sulfate solution in the later stage of ionization cannot be carried out uniformly, the pitting behavior is serious, and the flatness of the part after polishing cannot be guaranteed
When the electrolyte plasma polishing solution is used to remove the surface metamorphic layer of 316L stainless steel parts after hot isostatic pressing, due to the complex composition of the metamorphic layer and the strong binding force between the interface and the substrate, the organic acid solution cannot quickly cause the molecular structure change of the surface metamorphic layer at the initial stage , the salt solution cannot quickly trigger the plasma discharge channel and reach a certain scale. In the later stage, the surface metamorphic layer will be removed unevenly. Continued polishing will lead to sand spots on the part of the metamorphic layer that has been removed. There are sand spots on the surface of the final 316L stainless steel parts. spot, uneven brightness

Method used

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  • Method for removing deteriorated layer on stainless steel surface
  • Method for removing deteriorated layer on stainless steel surface
  • Method for removing deteriorated layer on stainless steel surface

Examples

Experimental program
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Effect test

Embodiment 1

[0044] (1) The preparation ratio (by weight) of the polishing liquid raw material additive: salt solution: water=1:10:180; The salt solution is ammonium sulfate and potassium chloride, and the ratio is 4:1; The additive contains 30% phosphoric acid, 60 % organic acid acetic acid, 10% complexing agent EDTMPS, obtain electrolyte plasma polishing fluid;

[0045] (2) Pour the prepared and evenly stirred electrolyte plasma polishing liquid into the polishing tank, and heat the polishing liquid to 70°C;

[0046] (3) According to the structural size of the 316L stainless steel parts, the polishing fixture and the pendant are used, and the 316L stainless steel parts with a metamorphic layer after the hot isostatic pressing are installed on the polishing pendant. Put the polishing fixture and the parts on the pendant into the above polishing tank, and completely immerse the parts in the polishing solution. The fixture and parts are connected to the positive pole of the power supply, an...

Embodiment 2

[0050] (1) The preparation ratio (by weight) of polishing fluid raw materials Additives: salt solution: water = 1:7:170; the salt solution is ammonium sulfate and barium chloride, the ratio is 4:1; the additive contains 40% phosphoric acid, 40 % organic acid acetic acid, 10% sodium gluconate, 10% complexing agent EDTMPS;

[0051] (2) Pour the prepared and evenly stirred electrolyte plasma polishing solution into the polishing tank until the temperature of the polishing solution is 75°C;

[0052] (3) Put the polishing fixture and parts on the pendant into the above polishing tank, and completely immerse the parts in the polishing solution; the fixture and parts are connected to the positive pole of the power supply, and the polishing tank is connected to the negative pole of the power supply, and the output voltage is controlled at 330V;

[0053] (4) The 316L stainless steel parts that produce a metamorphic layer after the hot isostatic pressing process are subjected to plasma ...

Embodiment 3

[0056] (1) The preparation ratio (by weight) of polishing fluid raw materials Additives: salt solution: water=1:8:200; salt solution contains 80% ammonium sulfate, 10% potassium chloride, 10% barium chloride; additive contains 50% % phosphoric acid, 30% organic acid acetic acid, 5% sodium gluconate, 15% complexing agent EDTMPS;

[0057] (2) Pour the prepared and evenly stirred electrolyte plasma polishing solution into the polishing tank until the temperature of the polishing solution is 80°C;

[0058] (3) Put the polishing fixture and parts on the pendant into the above polishing tank, and completely immerse the parts in the polishing solution; the fixture and parts are connected to the positive pole of the power supply, and the polishing tank is connected to the negative pole of the power supply, and the output voltage is controlled at 300V;

[0059] (4) The 316L stainless steel parts that produce a metamorphic layer after the hot isostatic pressing process are subjected to ...

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Abstract

The invention relates to a method for removing a deteriorated layer on the surface of stainless steel, and relates to the technical field of polishing. The method is used for stainless steel subjected to hot isostatic pressing treatment and comprises the steps that a polishing solution is prepared and poured into a polishing tank; the polishing solution is heated to a preset temperature, and the stainless steel part is placed in the polishing groove and immersed in the polishing solution; the stainless steel part is subjected to polishing treatment according to preset voltage and preset time; wherein the polishing solution comprises a salt solution, an additive and water, the salt solution is at least two of potassium chloride, barium chloride and ammonium sulfate, and the additive is at least one of phosphoric acid, acetic acid, ethylene diamine tetra (methylene sodium phosphate) and sodium gluconate. The polishing solution prepared from the salt solution, the additive and the water can effectively remove a metamorphic layer on the surface of the stainless steel part, so that the size precision of the part subjected to hot isostatic pressing treatment can be accurately controlled, and the product is good in surface smoothness, flat, smooth and bright in color.

Description

technical field [0001] The invention relates to the technical field of polishing, in particular to a method for removing a degenerated layer on the surface of stainless steel. Background technique [0002] Stainless steel products are widely used, such as stainless steel powder metallurgy parts used in gas turbines. In order to meet various application requirements, it is necessary to ensure the excellent material properties of stainless steel powder metallurgy parts. For example, in order to improve the material properties of 316L stainless steel products produced by injection molding technology, it is necessary to use hot isostatic pressing technology, but after the product is subjected to high-temperature and high-pressure hot isostatic pressing, a certain thickness (about 10-15 μm) appears on the surface of the product. metamorphic layer. On the one hand, the composition of the metamorphic layer is complex, mainly oxides such as chromium oxide and nickel oxide, and the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25F3/24
CPCC25F3/24
Inventor 王新锋刘李旭陈斌科向长淑苏腾飞孙恒超肖成桥
Owner 西安赛隆增材技术股份有限公司
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