CN102251211A - Formula of salt bath in salt bath nitridation treatment for stainless steel intake/exhaust valve and treatment method - Google Patents
Formula of salt bath in salt bath nitridation treatment for stainless steel intake/exhaust valve and treatment method Download PDFInfo
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- CN102251211A CN102251211A CN2010101793695A CN201010179369A CN102251211A CN 102251211 A CN102251211 A CN 102251211A CN 2010101793695 A CN2010101793695 A CN 2010101793695A CN 201010179369 A CN201010179369 A CN 201010179369A CN 102251211 A CN102251211 A CN 102251211A
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Abstract
The invention relates to a formula of a salt bath in salt bath nitridation treatment for a stainless steel intake/exhaust valve and a treatment method. The formula of the salt bath comprises the following components in percentage by weight: 13 to 40 percent of sodium cyanate, 8 to 20 percent of sodium carbonate, 30 to 55 percent of potassium carbonate, and 5 to 20 percent of sodium chloride. The formula has the advantages that: because the CNO concentration in the formula is low (8 to 25 percent) and Cl ions are added, the nitride structure with non-loose surface can be obtained even if the treatment is performed at a high temperature, and bright surface can be obtained by polishing after nitridation; and more importantly, the tolerance dimension of the nitrided exhaust valve welded by two materials is consistent with that before nitridation.
Description
Technical field
The present invention relates to a kind of stainless steel inlet and exhaust valve and carry out salt Bath Nitriding Treatment, relate in particular to salt bath formula and the treatment process used in this processing.
Background technology
In the stainless steel inlet and exhaust valve (the blast gate material is 4Cr9Si2, and the inlet valve material is 21-4N) for improving its wear resisting property and corrosion resistance nature.Require the surfaces nitrided layer thickness of inlet and exhaust valve more than 20 microns, surface hardness＞900Hv
0.2Usually adopt surperficial salt-bath nitriding technology,, generally need before and after nitrogenize, to carry out cleanup acid treatment, just easily obtain the outward appearance of uniformity after the nitrogenize again through oxide treatment because tectorium is thicker after the nitrogenize.
Salt-bath nitriding technology of the prior art is with CO
3And CNO
-Deng composition by certain proportioning, after melting at 570 ℃--580 ℃ workpiece inserted and handles for some time in the fused salt, make the CNO in the salt
-Decompose the back nitrogen-atoms and infiltrate the sosoloid that forms FeN compound and certain nitrogen atom concentration in the matrix.In order to improve the salt bath activity, CNO concentration and adds K generally more than 35% in the conventional nitridation salt
2S and a certain amount of Li
2CO
3But this method treatment time is long, and the surface easily produces thicker tectorium tissue.This tectorium can obviously reduce the wear-resisting and erosion resistance of valve, and influences its visual appearance.
Summary of the invention
The technical issues that need to address of the present invention have provided a kind ofly carries out salt bath formula in the salt Bath Nitriding Treatment to the stainless steel inlet and exhaust valve, is intended to solve the above problems.
In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions:
The present invention is made up of and components by weight percentage following compositions: Zassol (NaCNO) 13%-40%, yellow soda ash (Na
2CO
3) 8%-20%, salt of wormwood (K
2CO
3) 30%-55%, sodium-chlor (NaCl) 5-20%.
The present invention also provides a kind of salt Bath Nitriding Treatment method, realizes by following steps:
Degreasing: use the alkaline phosphatase salt brine solution, through the no greasy dirt of washing rear surface cleaning;
Preheating: adopt pit furnace, valve thermally equivalent when bell is installed blower fan and made preheating, the temperature difference is controlled at ± and 10 ℃; Temperature is between 250 ℃-350 ℃; Time is between 20-30 minute;
Nitrogenize: adopt salt bath formula, the nitriding treatment temperature is between 540 ℃-610 ℃, and the treatment time is 8-30 minute; Described salt bath formula is made up of and components by weight percentage following compositions: Zassol (NaCNO) 13%-40%, yellow soda ash (Na
2CO
3) 8%-20%, salt of wormwood (K
2CO
3) 30%-55%, sodium-chlor (NaCl) 5-20%.
Cooling: adopt air cooling, washing below the back air cooling to 200 ℃ of coming out of the stove.
Polishing.
Compared with prior art, the invention has the beneficial effects as follows: owing to CNO concentration low (8-25%) in prescription and adding Cl ion, still can obtain the nitrided structure that the surface nothing is loosened even at high temperature handle, nitrogenize is after polish the surface that can obtain light; What is more important is to the blast gate of two kinds of material welding, and the tolerance dimension of valve is preceding consistent with nitrogenize behind the via nitride.
Embodiment
Below in conjunction with embodiment the present invention is described in further detail:
The present invention is made up of and components by weight percentage following compositions: Zassol (NaCNO) 13%-40%, yellow soda ash (Na
2CO
3) 8%-20%, salt of wormwood (K
2CO
3) 30%-55%, sodium-chlor (NaCl) 5-20%.
Embodiment 1
Zassol (NaCNO) 36%, yellow soda ash (Na
2CO
3) 15%, salt of wormwood (K
2CO
3) 35%, sodium-chlor (NaCl) 14%.The nitriding process parameter is 540 ℃ of x25min
Embodiment 2
Zassol (NaCNO) 25%, yellow soda ash (Na
2CO
3) 17%, salt of wormwood (K
2CO
3) 38%, sodium-chlor (NaCl) 20%.The nitriding process parameter is 610 ℃ of x8min
All on sale in the said components market.
Mainly be to constitute in the component of this salt-bath nitriding by cyanate radical and carbonate, its reaction mechanism is that cyanate and oxygen reaction generate nitrogen and carbonate, wherein nitrogen-atoms infiltrates in the matrix, along with the carrying out used up cyanate radical and can be mended by adding regenerant salt of reaction, this prescription salt can recycle.
CNO
-+O
2→[C]+[N]+CO
3 2-
CO
3 2-+ Z (regenerant salt) → CNO-
Preparation method of the present invention is as follows:
Urea and carbonate and other component thorough mixing are put into crucible after evenly, and insulation can be produced in batches in 2 hours after 600 ℃ of high temperature melt.Use the same method and to obtain regenerant salt.
The mechanism of action of the present invention is: owing to added the active anion that contains Cl in the salt bath, and activate its workpiece surface, it is more easy to make that the infiltration of nitrogen becomes, even at low CNO
-Still can obtain infiltration rate faster under concentration and the low treatment temp.High-temperature ammonolysis then can reach the loose infiltration layer of needed nothing in the extremely short time.
Claims (4)
1. one kind is carried out salt bath formula in the salt Bath Nitriding Treatment to the stainless steel inlet and exhaust valve, is made up of and components by weight percentage following compositions: Zassol 13%-40%, yellow soda ash 8%-20%, salt of wormwood 30%-55%, sodium-chlor 5-20%.
2. according to claim 1 the stainless steel inlet and exhaust valve is carried out salt bath formula in the salt Bath Nitriding Treatment, wherein: Zassol 36%, yellow soda ash 15%, salt of wormwood 35%, sodium-chlor 14%.
3. according to claim 1 the stainless steel inlet and exhaust valve is carried out salt bath formula in the salt Bath Nitriding Treatment, wherein: Zassol (NaCNO) 25%, yellow soda ash (Na
2CO
3) 17%, salt of wormwood (K
2CO
3) 38%, sodium-chlor (NaCl) 20%.
4. one kind is carried out treatment process in the salt Bath Nitriding Treatment to the stainless steel inlet and exhaust valve, realizes by following steps:
Degreasing: use the alkaline phosphatase salt brine solution, through the no greasy dirt of washing rear surface cleaning;
Preheating: adopt pit furnace, valve thermally equivalent when bell is installed blower fan and made preheating, the temperature difference is controlled at ± and 10 ℃; Temperature is between 250 ℃-350 ℃; Time is between 20-30 minute;
Nitrogenize: adopt salt bath formula, the nitriding treatment temperature is between 540 ℃-610 ℃, and the treatment time is 8-30 minute; Described salt bath formula is made up of and components by weight percentage following compositions: Zassol 13%-40%, yellow soda ash 8%-20%, salt of wormwood 30%-55%, sodium-chlor 5-20%;
Cooling: adopt air cooling, washing below the back air cooling to 200 ℃ of coming out of the stove;
Polishing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010101793695A CN102251211A (en) | 2010-05-18 | 2010-05-18 | Formula of salt bath in salt bath nitridation treatment for stainless steel intake/exhaust valve and treatment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010101793695A CN102251211A (en) | 2010-05-18 | 2010-05-18 | Formula of salt bath in salt bath nitridation treatment for stainless steel intake/exhaust valve and treatment method |
Publications (1)
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|---|---|
| CN102251211A true CN102251211A (en) | 2011-11-23 |
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ID=44978773
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|---|---|---|---|
| CN2010101793695A Pending CN102251211A (en) | 2010-05-18 | 2010-05-18 | Formula of salt bath in salt bath nitridation treatment for stainless steel intake/exhaust valve and treatment method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106319438A (en) * | 2015-07-01 | 2017-01-11 | 杭州巨星科技股份有限公司 | Rare earth catalytic permeation QPQ composition and method for manufacturing high-speed cutting tool by QPQ process |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1338529A (en) * | 2000-08-14 | 2002-03-06 | 斯蒂芬流体力学与摩擦研究中心 | Surface treatment of mechanical parts with wear and corrosion simultaneously |
| CN1488007A (en) * | 2000-11-29 | 2004-04-07 | 帕克热处理工业株式会社 | Method of salt bath nitriding for producing iron member having improved corrosion resistance and iron parts |
-
2010
- 2010-05-18 CN CN2010101793695A patent/CN102251211A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1338529A (en) * | 2000-08-14 | 2002-03-06 | 斯蒂芬流体力学与摩擦研究中心 | Surface treatment of mechanical parts with wear and corrosion simultaneously |
| CN1488007A (en) * | 2000-11-29 | 2004-04-07 | 帕克热处理工业株式会社 | Method of salt bath nitriding for producing iron member having improved corrosion resistance and iron parts |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106319438A (en) * | 2015-07-01 | 2017-01-11 | 杭州巨星科技股份有限公司 | Rare earth catalytic permeation QPQ composition and method for manufacturing high-speed cutting tool by QPQ process |
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Application publication date: 20111123 |