CN104785772A - Valve guide pipe and powder metallurgy production process thereof - Google Patents
Valve guide pipe and powder metallurgy production process thereof Download PDFInfo
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- CN104785772A CN104785772A CN201510121604.6A CN201510121604A CN104785772A CN 104785772 A CN104785772 A CN 104785772A CN 201510121604 A CN201510121604 A CN 201510121604A CN 104785772 A CN104785772 A CN 104785772A
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- valve guide
- powder
- guide bushing
- sintering
- guide pipe
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Abstract
The invention discloses a valve guide pipe and a powder metallurgy production process thereof. The valve guide pipe is formed by proper powder raw materials at a time through the powder metallurgy production process, and is suitable for batch production, and a mould can be designed to be of a one-mould three-outlet structure, so that the production efficiency is further improved. The utilization rate of materials is high, the density uniformity of products is high, and the density difference between the ends and middle parts of a pressed blank is below 0.2g/ cm<3>. Meanwhile, a reasonable gap is reserved in the valve guide pipe, the valve guide pipe has good self-lubricating performance in the use process due to addition of sulphur, cutting machining of products is facilitated, and the requirements for the size precision and coaxiality of the guide pipe are met; graphite and copper are added, and the forming method of the pressed blank is improved, so that while the high-density pressed blank is obtained, the hardness and conquassation strength of the products are improved. It is detected that the pearlite content of the finally obtained valve guide pipe is larger than 50 percent, and the cementite content is smaller than 5 percent.
Description
Technical field
The present invention relates to a kind of valve guide bushing and powder metallurgical production technique thereof; Belong to component of machine processing technique field.
Background technology
Valve guide bushing is the upper requisite strength member guiding engine valve opening and closing campaign of engine (comprising gasoline engine and diesel engine), press-fited after in cylinder cap, ream machining must be carried out to its internal diameter, therefore, require that valve guide bushing aperture surface must have good wearability and machinability.When using plumbous gasoline, corresponding valve guide bushing generally uses the Special Casting Iron of casting pig, boracic or other elements and high-strength brass machining to produce, and stock utilization only has about 50%.Along with more and more higher to environmental requirement, doped fuel because of its exhaust emissions serious environment pollution, people are healthy is just progressively eliminated in harm.The main trend that unleaded gas is Overseas Development used instead by automobile, and this becomes a reality one after another in developed country, and China also starts to force to carry out using unleaded gas.The use of unleaded gas, the sulfide containing lead of the antifriction that makes originally to rely has not existed between valve guide bushing and valve stem, and cause traditional alloy cast iron valve guide bushing to occur Fast Wearing, service life obviously declines.
In prior art, valve guide bushing is cast iron manufacture method, adopt high-temperature molten melting process, its energy consumption is high, efficiency is low, and when conduit cool to room temperature, because core is different from the cooldown rate at edge, cause the tissue of product under room temperature different, edge is very fast because cooling, fine microstructures, core is slower because cooling, organize thick, cause internal stress comparatively large, easily produce processing and use distortion; And easy entrained air bubbles in cast, form gross blow hole at interiors of products, cause mechanical strength to decline.
Along with improving constantly of automobile engine performance requirement, the working condition of valve guide bushing is further harsh, requirements at the higher level are proposed to valve guide bushing performance, also with regard to inevitable requirement, its material and manufacturing process are improved, the exploitation of emerging powder metallurgy valve guide pipe just receives attention at home, but by dry various reasons, there are some problems in product quality, such as conduit intermediate density is low, easy fracture, conduit wears no resistance, the life-span is short, material machinability is poor, be difficult to ream endoporus etc., is not resolved for a long time, becomes the bottleneck of restriction valve guide bushing development.
Summary of the invention
For solving the deficiencies in the prior art, the object of the present invention is to provide a kind of valve guide bushing and powder metallurgical production technique thereof, obtained valve guide bushing has higher oil content, self-lubricating property and wearability good, be conducive to cutting, production efficiency is high, and even density, the density contrast of pressed compact end and middle part is at 0.2g/cm
3below.
In order to realize above-mentioned target, the present invention adopts following technical scheme:
A kind of valve guide bushing, is made up of powder metallurgical technique, powder stock and the mass percent of each raw material is as follows: 0.6 ~ 1.2% graphite, the copper of 0 ~ 1.5%, and the zinc stearate of 0.3 ~ 0.8%, the sulphur of 0.2 ~ 0.6%, surplus is iron powder.
Preferably, the powder diameter of foregoing graphites is 1500 orders.
More preferably, the powder diameter of aforementioned sulphur is 100-500 order.
Further, aforementioned iron powder is 100 order reduced iron powders.
In addition, the invention also discloses the powder metallurgical production technique of aforesaid a kind of valve guide bushing, comprise the steps:
S1, raw material mix: take each material powder by mass percent according to claim 1, then added in batch mixer by each material powder and mix, incorporation time is 60-70min;
S2, pressed compact are shaping: pour in mould, at 10t/cm by mixed raw material
2pressure under two-way compacting 5-10s, then under the off line power of 40T, deviate from die cavity, make pressed compact;
S3, sintering: step S2 is obtained pressed compact and sinter in net belt type sintering furnace, with nitrogen, hydrogen as protective atmosphere, omnidistance sintering time is 4-5 hour, and network speed is 60mm/min;
S4, machined: the product after sintering is carried out fine finishining, obtains the valve guide bushing of finished product.
Preferably, in abovementioned steps S3, net belt type sintering furnace has these three sintering zones of pre-burning district, Zheng Shao district and cooling zone, and wherein, the sintering temperature in pre-burning district is 600-900 DEG C, and sintering time is 1.5h; The sintering temperature in Zheng Shao district is 1110-1130 DEG C, and sintering time is 1h; Cooling zone comprises pre-cooling zone and normal temperature cooling zone, and the temperature of pre-cooling zone is 1100-1120 DEG C, and pre-coo time is 0.5h, and normal temperature cooling zone adopts recirculated water that sintered products is cooled to room temperature.By choose reasonable sintering process, temperature and time, while acquisition high density pressed compact, hardness and the crushing strength of product can be improved.
Further, in abovementioned steps S4, fine finishining comprises: rough turn external diameter, Vehicle Processing chamfering and mill external diameter process, to ensure the requirement of product axiality.
Usefulness of the present invention is: valve guide bushing of the present invention have selected suitable powder stock and adopts powder metallurgical technique to obtain, and once namely plastic, be applicable to mass production, mould also can be designed to a mould three and go out formula structure, enhances productivity further; And the utilization rate of material is high, product density uniformity is good, and the density contrast of pressed compact end and middle part is at 0.2g/cm
3below; Simultaneously, select suitable powder stock, containing rational space in the valve guide bushing adopting powder metallurgical technique of the present invention to produce to obtain, the interpolation of sulphur makes valve guide bushing in use have good self-lubricating property, also be conducive to the machining of product, ensure that the requirement of conduit dimensional accuracy and axiality; Add graphite and copper, simultaneously shaping to pressed compact method is improved, so just can while acquisition high density pressed compact, improve hardness and the crushing strength of product, after testing, the content of pearlite in alloy of the valve guide bushing finally obtained is greater than 50%, and cementite content is less than 5%.
Detailed description of the invention
Below in conjunction with specific embodiment, concrete introduction is done to the present invention.
Embodiment 1
The composition of the valve guide bushing of the present embodiment comprises by weight percentage: 1.2% graphite, the copper of 0.75%, the zinc stearate of 0.8%, the sulphur of 0.4%, and surplus is iron powder.
Production craft step is as follows:
S1, raw material mix: take each material powder by aforesaid mass percent, then added in batch mixer by each material powder and mix, incorporation time is 60-70min;
S2, pressed compact are shaping: pour in mould, at 10t/cm by mixed raw material
2pressure under two-way compacting 5-10s, then under the off line power of 40T, deviate from die cavity, make pressed compact;
S3, sintering: step S2 is obtained pressed compact and sinter in net belt type sintering furnace, with nitrogen, hydrogen as protective atmosphere, the sintering temperature in pre-burning district is 600-900 DEG C, and sintering time is 1.5h; The sintering temperature in Zheng Shao district is 1110-1130 DEG C, and sintering time is 1h; Cooling zone comprises pre-cooling zone and normal temperature cooling zone, and the temperature of pre-cooling zone is 1100-1120 DEG C, and pre-coo time is 0.5h, and normal temperature cooling zone adopts recirculated water that sintered products is cooled to room temperature; Controlling omnidistance sintering time is 4-5 hour, and network speed is 60mm/min;
S4, machined: the product after sintering is carried out fine finishining, obtains the valve guide bushing of finished product.
Detect the valve guide bushing of finished product, testing result shows: density is greater than 6.3g/cm
3, the density contrast of pressed compact end and middle part is at 0.2g/cm
3below, density homogeneity is good; Hardness is 80-120HB, and crushing strength is greater than 450Mpa.
Embodiment 2
The composition of the valve guide bushing of the present embodiment comprises by weight percentage: 0.6% graphite, the zinc stearate of 0.3%, the sulphur of 0.6%, and surplus is iron powder.
Production craft step is identical with embodiment 1, repeats no more.
Detect the valve guide bushing of finished product, testing result shows: density is greater than 6.4g/cm
3, the density contrast of pressed compact end and middle part is at 0.2g/cm
3below, density homogeneity is good; Hardness is 90-120HB, and crushing strength is greater than 460Mpa.
Embodiment 3
The composition of the valve guide bushing of the present embodiment comprises by weight percentage: 0.9% graphite, the copper of 1.5%, the zinc stearate of 0.6%, the sulphur of 0.2%, and surplus is iron powder.
Production craft step is identical with embodiment 1, repeats no more.
Detect the valve guide bushing of finished product, testing result shows: density is greater than 6.4g/cm
3, the density contrast of pressed compact end and middle part is at 0.2g/cm
3below, density homogeneity is good; Hardness is 100-120HB, and crushing strength is greater than 610Mpa.
To sum up, the present invention is by choose reasonable powder stock, the powder metallurgical technique improved is adopted to produce the valve guide bushing obtained, while acquisition high density pressed compact, optimize the density homogeneity of product, solve puzzlement of the prior art, further improves hardness and the crushing strength of product simultaneously.
More than show and describe general principle of the present invention, principal character and advantage.The technical staff of the industry should understand, and above-described embodiment does not limit the present invention in any form, the technical scheme that the mode that all employings are equal to replacement or equivalent transformation obtains, and all drops in protection scope of the present invention.
Claims (7)
1. a valve guide bushing, is characterized in that, is made up of powder metallurgical technique, powder stock and the mass percent of each raw material is as follows: 0.6 ~ 1.2% graphite, the copper of 0 ~ 1.5%, and the zinc stearate of 0.3 ~ 0.8%, the sulphur of 0.2 ~ 0.6%, surplus is iron powder.
2. a kind of valve guide bushing according to claim 1, is characterized in that, the powder diameter of described graphite is 1500 orders.
3. a kind of valve guide bushing according to claim 1, is characterized in that, the powder diameter of described sulphur is 100-500 order.
4. a kind of valve guide bushing according to claim 1, is characterized in that, described iron powder is 100 order reduced iron powders.
5. the powder metallurgical production technique of a kind of valve guide bushing as claimed in claim 1, is characterized in that, comprise the steps:
S1, raw material mix: take each material powder by mass percent according to claim 1, then added in batch mixer by each material powder and mix, incorporation time is 60-70min;
S2, pressed compact are shaping: pour in mould, at 10t/cm by mixed raw material
2pressure under two-way compacting 5-10s, then under the off line power of 40T, deviate from die cavity, make pressed compact;
S3, sintering: step S2 is obtained pressed compact and sinter in net belt type sintering furnace, with nitrogen, hydrogen as protective atmosphere, omnidistance sintering time is 4-5 hour, and network speed is 60mm/min;
S4, machined: the product after sintering is carried out fine finishining, obtains the valve guide bushing of finished product.
6. the powder metallurgical production technique of a kind of valve guide bushing according to claim 5, is characterized in that, in described step S3, net belt type sintering furnace has these three sintering zones of pre-burning district, Zheng Shao district and cooling zone, wherein, the sintering temperature in pre-burning district is 600-900 DEG C, and sintering time is 1.5h; The sintering temperature in Zheng Shao district is 1110-1130 DEG C, and sintering time is 1h; Cooling zone comprises pre-cooling zone and normal temperature cooling zone, and the temperature of pre-cooling zone is 1100-1120 DEG C, and pre-coo time is 0.5h, and normal temperature cooling zone adopts recirculated water that sintered products is cooled to room temperature.
7. the powder metallurgical production technique of a kind of valve guide bushing according to claim 5, is characterized in that, in described step S4, fine finishining comprises: rough turn external diameter, Vehicle Processing chamfering and mill external diameter process, to ensure the requirement of product axiality.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510121604.6A CN104785772A (en) | 2015-03-19 | 2015-03-19 | Valve guide pipe and powder metallurgy production process thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510121604.6A CN104785772A (en) | 2015-03-19 | 2015-03-19 | Valve guide pipe and powder metallurgy production process thereof |
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| CN104785772A true CN104785772A (en) | 2015-07-22 |
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| CN201510121604.6A Pending CN104785772A (en) | 2015-03-19 | 2015-03-19 | Valve guide pipe and powder metallurgy production process thereof |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105149596A (en) * | 2015-08-31 | 2015-12-16 | 苏州莱特复合材料有限公司 | Powder metallurgy valve gas pipe and preparation method thereof |
| CN106216657A (en) * | 2016-07-27 | 2016-12-14 | 合肥波林新材料股份有限公司 | A kind of plunger displacement pump return plate manufacture method |
| CN106566974A (en) * | 2016-11-01 | 2017-04-19 | 安徽恒均粉末冶金科技股份有限公司 | Automobile magnetic water pump powder metallurgy inner/outer magnet ring and preparation method thereof |
| CN107262724A (en) * | 2017-05-22 | 2017-10-20 | 东风汽车零部件（集团）有限公司东风粉末冶金公司 | A kind of natural gas and gasoline dual fuel engine valve guide bushing material |
| CN111633213A (en) * | 2020-06-03 | 2020-09-08 | 奇瑞汽车股份有限公司 | Valve guide pipe manufacturing method, valve guide pipe and automobile |
| CN111788025A (en) * | 2018-02-23 | 2020-10-16 | 日立化成株式会社 | Sintered valve guide and method for manufacturing same |
| CN112974794A (en) * | 2021-02-03 | 2021-06-18 | 仪征亚新科双环活塞环有限公司 | Powder metallurgy valve guide pipe and preparation method thereof |
| CN113881903A (en) * | 2021-09-01 | 2022-01-04 | 安徽金亿新材料股份有限公司 | Application of Chang' e steel in preparation of valve guide or multi-step complex structural part, valve guide and multi-step complex structural part and preparation |
-
2015
- 2015-03-19 CN CN201510121604.6A patent/CN104785772A/en active Pending
Non-Patent Citations (2)
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| 和存正: "铁基气门导管材料性能的控制", 《粉末冶金工业》 * |
| 王鸿灏: "粉末冶金气门导管内孔及其直线度的控制", 《粉末冶金工业》 * |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105149596A (en) * | 2015-08-31 | 2015-12-16 | 苏州莱特复合材料有限公司 | Powder metallurgy valve gas pipe and preparation method thereof |
| CN106216657A (en) * | 2016-07-27 | 2016-12-14 | 合肥波林新材料股份有限公司 | A kind of plunger displacement pump return plate manufacture method |
| CN106216657B (en) * | 2016-07-27 | 2018-05-22 | 合肥波林新材料股份有限公司 | A kind of plunger pump backhaul disc manufacturing method |
| CN106566974A (en) * | 2016-11-01 | 2017-04-19 | 安徽恒均粉末冶金科技股份有限公司 | Automobile magnetic water pump powder metallurgy inner/outer magnet ring and preparation method thereof |
| CN107262724A (en) * | 2017-05-22 | 2017-10-20 | 东风汽车零部件（集团）有限公司东风粉末冶金公司 | A kind of natural gas and gasoline dual fuel engine valve guide bushing material |
| CN107262724B (en) * | 2017-05-22 | 2019-11-05 | 东风汽车零部件（集团）有限公司东风粉末冶金公司 | A kind of natural gas and gasoline dual fuel engine valve guide bushing material |
| CN111788025A (en) * | 2018-02-23 | 2020-10-16 | 日立化成株式会社 | Sintered valve guide and method for manufacturing same |
| CN111633213A (en) * | 2020-06-03 | 2020-09-08 | 奇瑞汽车股份有限公司 | Valve guide pipe manufacturing method, valve guide pipe and automobile |
| CN112974794A (en) * | 2021-02-03 | 2021-06-18 | 仪征亚新科双环活塞环有限公司 | Powder metallurgy valve guide pipe and preparation method thereof |
| CN112974794B (en) * | 2021-02-03 | 2023-11-03 | 仪征亚新科双环活塞环有限公司 | Powder metallurgy valve guide |
| CN113881903A (en) * | 2021-09-01 | 2022-01-04 | 安徽金亿新材料股份有限公司 | Application of Chang' e steel in preparation of valve guide or multi-step complex structural part, valve guide and multi-step complex structural part and preparation |
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Application publication date: 20150722 |
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