CN102181782A - Method for manufacturing high-nickel austenitic ductile cast iron valve rod nut - Google Patents
Method for manufacturing high-nickel austenitic ductile cast iron valve rod nut Download PDFInfo
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- CN102181782A CN102181782A CN2011100921347A CN201110092134A CN102181782A CN 102181782 A CN102181782 A CN 102181782A CN 2011100921347 A CN2011100921347 A CN 2011100921347A CN 201110092134 A CN201110092134 A CN 201110092134A CN 102181782 A CN102181782 A CN 102181782A
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- cast iron
- valve rod
- nickel
- rod nut
- stem nut
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Abstract
The invention belongs to the manufacturing field of valves, in particular relates to a method for manufacturing a high-nickel austenitic ductile cast iron valve rod nut. The selected material comprises the following ingredients: not more than 3.0% of carbon, 1.5-3.0% of silicon, 0.7-1.2% of manganese, 1.75-2.75% of chromium, 18-22% of nickel and not more than 0.08% of phosphorus. The mechanical performances of the high-nickel austenitic ductile cast iron valve rod nut are obtained as follows: the tensile strength is not less than 400 MPa, the yield strength is not less than 207 MPa, the elongation is not less than 8%, and the hardness is 139-202 HB; in the structure of the valve rod nut, spherical graphite is distributed on an austenitic matrix; and a small amount of carbides are contained in the valve rod nut. The method totally comprises nine steps of (1) molding and core-making, (2) smelting, (3) spheroidizing, (4) inoculating, (5) pre-reflow detecting, (6) casting, (7) post-reflow detecting, (8) clearing and rough processing and (9) fine machining by using a machine tool. The method provided by the invention has the following advantages that: good corrosion resistance, high temperature resistance and resistance to oxidation are obtained for the selected valve rod nut material; meanwhile, good low thermal expansion and low temperature impact toughness are also obtained so that various severe working environments of the valve rod nut are completely satisfied.
Description
Technical field
The invention belongs to valve and make the field, relate in particular to a kind of D-2 of use type high-nickel austenite nodular cast iron as material the valve stem nut manufacture method.
Background technology
Valve stem nut is to be used for valve opening and to cut out, combine the critical valves part that carries out work with parts such as valve plate, valve rods, how to select for use suitable material to make valve stem nut, making it have heatproof, withstand voltage, corrosion resistant superperformance in atrocious weather and Working environment, is the crux of making valve stem nut.
The material of existing manufacturing valve stem nut mainly is common steel, cast iron or aluminium bronze, the former is for the defective at aspect such as against corrosion, anti-oxidant, heat-resisting, make valve stem nut easily with the valve rod rust extremely, directly influence the work-ing life of valve, latter's xantal, its major ingredient 90-95% is that copper, 5-10% are aluminium, though have certain corrosion resistance nature, intensity is relatively poor, and manufacturing cost is bigger, therefore selecting a kind of novel equivalent material for use, is the key of making valve stem nut.
Summary of the invention
The invention provides valve stem nut and manufacture method thereof that a kind of brand-new material is made.
Concrete technical scheme: a kind of valve stem nut of D-2 type high-nickel austenite nodular cast iron manufacturing of selecting for use is with manufacture method, selected material composition is carbon≤3.0%, silicon 1.5-3.0%, manganese 0.7-1.2%, chromium 1.75-2.75%, nickel 18-22%, phosphorus≤0.08%.Mechanical property is tensile strength 〉=400MPA, yield strength 〉=207MPA, and unit elongation 〉=8%, hardness 139-202HB, it is organized as distribution globular graphite on the austenitic matrix, and contains minor amount of carbide, and behind the selected material, making method is divided into:
1, molding and core making, 2, melting, 3. spheroidizing, 4. inoculation, 5, the stokehold detects, 6, cast, 7, detect behind the stove, 8, cleaning and roughing, 9, totally 9 steps such as the meticulous machining of lathe,
Usefulness of the present invention is that selected valve rod sieve parent material has good solidity to corrosion, high temperature resistant, oxidation-resistance, and good low heat expansion property and low-temperature impact toughness are arranged simultaneously, meets the various abominable Working environment of a stem nut fully.
Embodiment
To further specify the specific embodiment of the present invention below:
By composition and the mechanical property and the matrix composition requirement of the material of being made in the above-mentioned summary of the invention, selected material, making D-2 type high-nickel austenite nodular cast iron by nine following steps is the valve stem nut of material.
1, molding and core making
With the roughing sand of 20-70 purpose casting, mix system clay-bonded sand and be used to make external form, be coated with behind the graphite paint, the drying room about 400 ℃ is dried, and core adopts tung oil sand to make oven dry.
2, melting
With the magnesium iron pig iron is major ingredient, wherein: carbon 〉=4.0, silicon≤1.0, manganese≤0.3, phosphorus≤0.05, sulphur≤0.03.Alloy material adopts sheet nickel, contains the mid-carbon fe-mn of manganese 80%, contains the high carbon ferro-chrome of chromium 60 or more, the adding of content shown in according to the form below melting, and smelting temperature is to 1480-1500 ℃, tapping temperature 〉=1470 ℃.
3, spheroidizing
Nodulizing agent is selected rare earth ferrosilicon edge alloy for use, and add-on is 1.2-2.0%, adopts pit to pour method.
4, inoculation
Select the nucleating agent that contains strontium for use, add-on is that outer 0.8-1.2%. does the late inoculation processing respectively in the nodularization process and after the nodularization.
5, the stokehold is detected
1. adopt thermal analyzer to detect the carbon of solution, broken content and carbon equivalent, and tentatively judge its nodularization rate.
2. adopt the chill block assay method to judge its nodularization effect.
3. get metallographic specimen and make, and determine its nodularization rate in order to carrying out metallographic behind the stove.
6. cast
After nodularization, inoculation finish, to skim at once, teeming temperature is controlled at 1400--1440 ℃, and pours into a mould in 10 minutes and finish.
7, detect behind the stove
Carry out chemical analysis behind the stove and detect, guarantee that various alloying elements are all within the scope of defined.
To the metallographic specimen polishing, under metaloscope, observe, judge that its nodularization rate should guarantee more than II level nodularization rate.
8, cleaning and roughing
The successful high bright and beautiful austenite ductile iron valve stem nut foundry goods of casting is roughly selected, found that in time outward appearance casting flaws such as knockout, slag inclusion, core shift, shrinkage cavity are to guarantee that product is qualified.
9, meticulous the cutting of lathe thanks to processing
According to the specification needs of joining valve, carry out lathe and cut and thank to processing.Finish the manufacturing of D-2 type high-nickel austenitic cast iron valve stem nut.
Have good nodularization rate by 9 above-mentioned step process method output materials, meet the valve stem nut of service requirements.
Claims (7)
1. high-nickel austenite nodular cast iron valve-stem nut manufacture method, selected material composition is carbon≤3.0%, silicon 1.5-3.0%, manganese 0.7-1.2%, chromium 1.75-2.75%, nickel 18-22%, phosphorus≤0.08%.Mechanical property is tensile strength 〉=400MPA, yield strength 〉=207MPA, unit elongation 〉=8%, hardness 139-202HB, it is organized as distribution globular graphite on the austenitic matrix, and contains minor amount of carbide, it is characterized in that making method is divided into: 1, molding and core making, 2, melting, 3. spheroidizing, 4. inoculation, 5, the stokehold detects, 6, cast, 7, detect 8, cleaning and roughing, 9, totally 9 steps such as the meticulous machining of lathe behind the stove.
2. according to claim 1, a kind of high-nickel austenite nodular cast iron valve-stem nut manufacture method, it is characterized in that, described molding and core making, with the roughing sand of 20-70 purpose casting, mix system clay-bonded sand and be used to make external form, be coated with behind the graphite paint, drying room about 400 ℃ is dried, and core adopts tung oil sand to make oven dry.
3. according to claim 1, a kind of high-nickel austenite nodular cast iron valve-stem nut manufacture method is characterized in that, described melting is a major ingredient with the magnesium iron pig iron, wherein: carbon 〉=4.0, silicon≤1.0, manganese≤0.3, phosphorus≤0.05, sulphur≤0.03.Alloy material adopts sheet nickel, contains the mid-carbon fe-mn of manganese 80%, contains the high carbon ferro-chrome of chromium 60 or more, the adding of content shown in according to the form below melting, and smelting temperature is to 1480-1500 ℃, tapping temperature 〉=1470 ℃,
4. according to claim 1, a kind of high-nickel austenite nodular cast iron valve-stem nut manufacture method is characterized in that, described spheroidizing, and nodulizing agent is selected rare earth ferrosilicon edge alloy for use, and add-on is 1.2-2.0%, adopts pit to pour method.
5. according to claim 1, a kind of high-nickel austenite nodular cast iron valve-stem nut manufacture method is characterized in that, described inoculation, select the nucleating agent that contains strontium for use, add-on is that outer 0.8-1.2%. does the late inoculation processing respectively in the nodularization process and after the nodularization.
6. according to claim 1, a kind of high-nickel austenite nodular cast iron valve-stem nut manufacture method, it is characterized in that, described, stokehold is detected, 1. adopt thermal analyzer to detect the carbon of solution, broken content and carbon equivalent, and tentatively judge its nodularization rate, 2. adopt the chill block assay method to judge its nodularization effect, 3. get metallographic specimen and make, and determine its nodularization rate in order to carrying out metallographic behind the stove.
7. according to claim 1, a kind of high-nickel austenite nodular cast iron valve-stem nut manufacture method is characterized in that, described be cast in nodularization, inoculation and finish after, skim, teeming temperature is controlled at 1400--1440 ℃ at once, and pours into a mould in 10 minutes and finish.
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CN2011100921347A CN102181782A (en) | 2011-04-11 | 2011-04-11 | Method for manufacturing high-nickel austenitic ductile cast iron valve rod nut |
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CN2011100921347A CN102181782A (en) | 2011-04-11 | 2011-04-11 | Method for manufacturing high-nickel austenitic ductile cast iron valve rod nut |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103185058A (en) * | 2011-12-29 | 2013-07-03 | 财团法人金属工业研究发展中心 | Low thermal expansion screw |
CN104451356A (en) * | 2014-11-11 | 2015-03-25 | 衡阳市朝阳汽车配件制造有限公司 | High-nickel austenitic spheroidal graphite cast iron and preparation method thereof |
CN105950959A (en) * | 2016-07-18 | 2016-09-21 | 安徽德宝压缩机有限公司 | High-nickel austenite nodular cast iron and production technique for same |
CN108004460A (en) * | 2017-12-18 | 2018-05-08 | 武汉理工大学 | A kind of high-intensity and high-tenacity as cast condition QT800-5 spheroidal graphite cast-iron and its production method |
CN109356987A (en) * | 2018-12-21 | 2019-02-19 | 盐城市精工铸业股份有限公司 | High-nickel austenite nodular cast iron valve-stem nut and its manufacturing method |
CN109482815A (en) * | 2018-12-21 | 2019-03-19 | 盐城市精工铸业股份有限公司 | The casting technique of high-nickel austenite nodular cast iron valve-stem nut |
-
2011
- 2011-04-11 CN CN2011100921347A patent/CN102181782A/en active Pending
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103185058A (en) * | 2011-12-29 | 2013-07-03 | 财团法人金属工业研究发展中心 | Low thermal expansion screw |
CN103185058B (en) * | 2011-12-29 | 2015-04-08 | 财团法人金属工业研究发展中心 | Low thermal expansion screw |
CN104451356A (en) * | 2014-11-11 | 2015-03-25 | 衡阳市朝阳汽车配件制造有限公司 | High-nickel austenitic spheroidal graphite cast iron and preparation method thereof |
CN105950959A (en) * | 2016-07-18 | 2016-09-21 | 安徽德宝压缩机有限公司 | High-nickel austenite nodular cast iron and production technique for same |
CN108004460A (en) * | 2017-12-18 | 2018-05-08 | 武汉理工大学 | A kind of high-intensity and high-tenacity as cast condition QT800-5 spheroidal graphite cast-iron and its production method |
CN108004460B (en) * | 2017-12-18 | 2019-12-27 | 武汉理工大学 | High-strength high-toughness as-cast QT800-5 nodular cast iron and production method thereof |
CN109356987A (en) * | 2018-12-21 | 2019-02-19 | 盐城市精工铸业股份有限公司 | High-nickel austenite nodular cast iron valve-stem nut and its manufacturing method |
CN109482815A (en) * | 2018-12-21 | 2019-03-19 | 盐城市精工铸业股份有限公司 | The casting technique of high-nickel austenite nodular cast iron valve-stem nut |
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Application publication date: 20110914 |