CN100350069C - Method for nitriding stainless steel parts for steam turbine and gasturbine - Google Patents
Method for nitriding stainless steel parts for steam turbine and gasturbine Download PDFInfo
- Publication number
- CN100350069C CN100350069C CNB2004100436322A CN200410043632A CN100350069C CN 100350069 C CN100350069 C CN 100350069C CN B2004100436322 A CNB2004100436322 A CN B2004100436322A CN 200410043632 A CN200410043632 A CN 200410043632A CN 100350069 C CN100350069 C CN 100350069C
- Authority
- CN
- China
- Prior art keywords
- nitriding
- stainless steel
- parts
- furnace
- pill
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005121 nitriding Methods 0.000 title claims abstract description 37
- 239000010935 stainless steel Substances 0.000 title claims abstract description 35
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 35
- 238000000034 method Methods 0.000 title claims abstract description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000006187 pill Substances 0.000 claims abstract description 21
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 14
- 229910052742 iron Inorganic materials 0.000 claims abstract description 12
- 239000010410 layer Substances 0.000 claims abstract description 12
- 239000008187 granular material Substances 0.000 claims abstract description 8
- 239000002344 surface layer Substances 0.000 claims abstract description 6
- 239000000843 powder Substances 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 6
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 5
- 239000004800 polyvinyl chloride Substances 0.000 claims description 5
- 239000011347 resin Substances 0.000 claims description 5
- 229920005989 resin Polymers 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 3
- 229910021529 ammonia Inorganic materials 0.000 abstract description 3
- 230000007797 corrosion Effects 0.000 abstract description 3
- 238000005260 corrosion Methods 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 9
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- 125000004433 nitrogen atom Chemical group N* 0.000 description 6
- 235000019270 ammonium chloride Nutrition 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 3
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 238000002161 passivation Methods 0.000 description 3
- 238000005488 sandblasting Methods 0.000 description 3
- 229910021556 Chromium(III) chloride Inorganic materials 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 229960000359 chromic chloride Drugs 0.000 description 2
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000005501 phase interface Effects 0.000 description 2
- 208000028571 Occupational disease Diseases 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- CXOWYMLTGOFURZ-UHFFFAOYSA-N azanylidynechromium Chemical compound [Cr]#N CXOWYMLTGOFURZ-UHFFFAOYSA-N 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
The present invention relates to a nitriding method of stainless steel parts of steam turbines and gas turbines, particularly to a nitriding technology of stainless steel parts, which is carried out according to the following steps that a. pill granules are divided in three equal parts and respectively put in an iron box, wherein the addition quantity of the pills is from 0.1 to 0.3g/(Kg stainless steel); b. the iron boxes well respectively containing the three equal parts of the pill granules are put on an upper part, a middle part and a lower part of a nitriding tool or a nitriding furnace; c. ammonia is continuously inputted in the furnace, and the stainless steel part is heated in nitriding atmosphere for 6 to 80 hours under the condition of the temperature of 540 to 640 DEG C so that a nitriding layer with the thickness of 0.1 to 0.7mm is formed on the surface layer of the stainless steel part. The present invention improves the corrosion resistance and surface hardness by the nitriding layer formed on the stainless steel surface and has the advantages of simple operation, reduction of personal damage to an operator, low cost and stable nitriding quality and product quality.
Description
The technical field is as follows:
the invention relates to a nitriding process of stainless steel parts.
Background art:
the passivation film hinders the penetration of nitrogen atoms due to the passivation film on the surface of the stainless steel. The removal of the passivation film is one of the keys to nitridation. The original methods for removing the passive film comprise four methods of sand blasting, acid washing, ammonium chloride adding and electrolytic gas phase catalysis, wherein the passive film removal by sand blasting requires that the passive film is immediately put into a furnace after sand blasting, the operation of large pieces is difficult, and operators are easy to suffer from occupational diseases; the cost of adding ammonium chloride to remove the passive film is high, and the excessive ammonium chloride can corrode the surface of a workpiece to generate pits; pickling to remove the passive film has certain danger to the body of an operator and requires immediate furnace entry; the electrolytic gas phase catalysis is adopted to remove the passive film, and the mixture of concentrated sulfuric acid and salt is very easy to threaten the personal safety of operators.
The invention content is as follows:
the invention aims to provide a nitriding method for stainless steel parts of steam turbines and gas turbines, which can improve the corrosion resistance and surface hardness of stainless steel parts by removing a passive film on the surface of stainless steel to easily form a nitrided layer on the surface of stainless steel, and has the advantages of simple operation, capability of reducing the personal damage to operators, low cost, stable nitriding quality and stable product quality. The invention is carried out according to the following steps: a. dividing pill granules or medicinal powder into three equal parts, and respectively placing into an iron box, wherein the addition amount of the pill is 0.1-0.3 g/Kg stainless steel, and the main chemical component of the pill granules or medicinal powder is polyvinyl chloride resin (CH) with various types2CHCl)n(ii) a b. Placing the iron box with the three equally-divided pill particles or medicinal powder on the upper, middle and lower parts of a nitriding tool or a nitriding furnace; c. continuously feeding ammonia gas into the furnace, and heating the stainless steel part in a nitriding atmosphere at 540-640 ℃ for 6-80 hours to form a nitriding layer with the thickness of 0.1-0.7 mm on the surface layer of the stainless steel part. The nitriding process of the invention comprises the following steps: continuously introducing ammonia gas into the furnace, and enabling ammonia molecules to migrate to the metal surface and be adsorbed on the metal surface; ammonia molecules are continuously decomposed on a phase interface to form nitrogen atoms and hydrogen atoms; the active atoms are compounded into molecules, and continuously pass through the diffusion layer boundary of phase interface reaction and continuously pass through the furnaceRemoving nitrogen atoms adsorbed on the surface of the metal, dissolving the nitrogen atoms in α -Fe, diffusing the nitrogen atoms from the surface of the metal to the inside of the metal to generate a corresponding concentration gradient, starting to form nitrides on the surface when the solubility in α -Fe is exceeded, growing the nitrides in the vertical direction and the parallel direction of the surface of the metal, forming a gamma' phase and an epsilon phase on the surface of the metal in sequence, continuously thickening the nitride layer, and removing the nitrogen atoms from the nitridesThe layer diffuses into the metal. The reaction mechanism is as follows: decomposing the pills at 540-640 ℃, and reacting with ammonia gas to generate ammonium chloride, hydrogen chloride gas and methane gas; hydrogen chloride gas and oxide film (Cr)2O3) Reacting to generate chromium trichloride and water vapor; reacting chromium trichloride with ammonia gas to generate chromium nitride and hydrogen chloride gas; while the above reaction is completed, the step of the basic process of nitriding is also performed, and the chemical reaction formula is as follows:
the invention adopts pills as a method for removing the passive film on the surface of stainless steel nitriding workpieces of all steam turbines and gas turbines, and the method ensures that the surface of the stainless steel is easy to form a nitriding layer by removing the passive film on the surface of the stainless steel so as to improve the corrosion resistance and the surface hardness of stainless steel parts.
The specific implementation mode is as follows:
the first embodiment is as follows: the implementation mode is carried out according to the following steps: a. dividing pill particles or medicinal powder into three equal parts, and respectively putting the three equal parts into an iron box, wherein the adding amount of pills is 0.1-0.3 g/Kg of stainless steel; b.placing the iron box with the three equally-divided pill particles or medicinal powder on the upper, middle and lower parts of a nitriding tool or a nitriding furnace; c. continuously feeding ammonia gas and stainless steel into the furnaceHeating the part in a nitriding atmosphere at 540-640 ℃ for 6-80 hours to form a nitriding layer with a thickness of 0.1-0.7 mm on the surface layer of the stainless steel part. The pill comprises various types of polyvinyl chloride resin (CH) as main chemical component2CHCl)n。
The second embodiment is as follows: the implementation mode is carried out according to the following steps: a. dividing polyvinyl chloride resin particles into three equal parts, and respectively putting the three equal parts into an iron box, wherein the adding amount of pills is 0.2g/Kg of stainless steel; b. placing the iron boxes filled with the three equal parts of pill granules on the upper part, the middle part and the lower part of a nitriding furnace; c. continuously inputting ammonia gas into the furnace, and heating the stainless steel part in a nitriding atmosphere at the temperature of 540-640 ℃ for 6-80 hours to form a nitriding layer with the thickness of more than or equal to 0.15mm on the surface layer of the stainless steel part.
Claims (2)
1. The nitriding method of the stainless steel parts of the steam turbine and the gas turbine is characterized by comprising the following steps of: a. dividing pill granules or medicinal powder into three equal parts, and respectively placing into an iron box, wherein the addition amount of the pill is 0.1-0.3 g/Kg stainless steel, and the main chemical component of the pill granules or medicinal powder is polyvinyl chloride resin (CH) with various types2CHCl)n(ii) a b. Placing the iron box with the three equally-divided pill particles or medicinal powder on the upper, middle and lower parts of a nitriding tool or a nitriding furnace; c. continuously feeding ammonia gas into the furnace, and heating the stainless steel part in a nitriding atmosphere at 540-640 ℃ for 6-80 hours to form a nitriding layer with the thickness of 0.1-0.7 mm on the surface layer of the stainless steel part.
2. The nitriding method for stainless steel parts of steam turbines and gas turbines as claimed in claim 1, characterized by comprising the steps of: a. dividing polyvinyl chloride resin particles into three equal parts, and respectively putting the three equal parts into an iron box, wherein the adding amount of pills is 0.2g/Kg of stainless steel; b. placing the iron boxes filled with the three equal parts of pill granules on the upper part, the middle part and the lower part of a nitriding furnace; c. continuously inputting ammonia gas into the furnace, and heating the stainless steel part in a nitriding atmosphere at the temperature of 540-640 ℃ for 6-80 hours to form a nitriding layer with the thickness of more than or equal to 0.15mm on the surface layer of the stainless steel part.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100436322A CN100350069C (en) | 2004-06-16 | 2004-06-16 | Method for nitriding stainless steel parts for steam turbine and gasturbine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100436322A CN100350069C (en) | 2004-06-16 | 2004-06-16 | Method for nitriding stainless steel parts for steam turbine and gasturbine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1710143A CN1710143A (en) | 2005-12-21 |
| CN100350069C true CN100350069C (en) | 2007-11-21 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100436322A Expired - Lifetime CN100350069C (en) | 2004-06-16 | 2004-06-16 | Method for nitriding stainless steel parts for steam turbine and gasturbine |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100350069C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104250720B (en) * | 2014-09-15 | 2016-07-27 | 哈尔滨汽轮机厂有限责任公司 | A kind of method shortening the structural alloy steel gas nitriding technique time |
| CN106868446B (en) * | 2017-02-21 | 2019-03-12 | 哈尔滨汽轮机厂有限责任公司 | Stainless steel nitriding method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1091780A (en) * | 1993-03-01 | 1994-09-07 | 大同酸素株式会社 | Nitrided stainless steel products |
-
2004
- 2004-06-16 CN CNB2004100436322A patent/CN100350069C/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1091780A (en) * | 1993-03-01 | 1994-09-07 | 大同酸素株式会社 | Nitrided stainless steel products |
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| Publication number | Publication date |
|---|---|
| CN1710143A (en) | 2005-12-21 |
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| Date | Code | Title | Description |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Assignee: GUANGZHOU ZHUJIANG NATURAL GAS POWER GENERATION Co.,Ltd. Assignor: HARBIN TURBINE Co.,Ltd. Contract record no.: 2010440000566 Denomination of invention: Method for nitriding stainless steel parts for steam turbine and gasturbine Granted publication date: 20071121 License type: Exclusive License Open date: 20051221 Record date: 20100528 |
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| CX01 | Expiry of patent term |
Granted publication date: 20071121 |