CN103614526A - Method for hardening valve surface of gas valve of diesel engine - Google Patents
Method for hardening valve surface of gas valve of diesel engine Download PDFInfo
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- CN103614526A CN103614526A CN201310654462.0A CN201310654462A CN103614526A CN 103614526 A CN103614526 A CN 103614526A CN 201310654462 A CN201310654462 A CN 201310654462A CN 103614526 A CN103614526 A CN 103614526A
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Abstract
The invention discloses a method for hardening the valve surface of a NiCr20TiAl-gas valve of a diesel engine. The method comprises the steps of preheating, primary heating rolling, re-preheating, secondary heating rolling, thrice heating rolling, and aging treatment. According to the method disclosed by the invention, the depth of a hardened layer on the valve surface of the NiCr20TiAl-gas valve of the diesel engine is greater than that of a the same hardened layer formed by cold extrusion pressure by more than 2mm under the same condition and is more than three times of that of the cold-extruded hardened layer, and the depth of the hardened layer on the valve surface of the NiCr20TiAl-gas valve of the diesel engine can be up to 2.9-3.3mm; and therefore, the fatigue intensity and the reliability of the gas valve are obviously improved, and the service life is prolonged.
Description
Technical field
The present invention relates to the thermal treatment process of diesel valve, specifically, the method that particularly a kind of diesel engine NiCr20TiAl air valve valve face processed hardens.
Background technology
NiCr20TiAl air valve processed is one of critical movements part of diesel engine heart, is again fundamental parts and the consumable product of diesel engine.
As heart movement part, it is the critical movements part that determines diesel engine performance and reliability.
As basic part, it plays a very important role diesel engine.
Air valve in use lost efficacy, and will directly produce the serious consequences such as the distortion of the component such as main frame cylinder, piston, supercharging blower or damage.
Because air valve is running stores, occupy heart, in the time of changing, diesel engine needs to disintegrate, and work consuming is consuming time, in use breaks down and must cause parking accident, particularly marine diesel, and air valve lost efficacy the loss causing will be larger.
In order to improve wear resistance, fatigue strength and the work-ing life of air valve valve face, China introduces the types such as DK machine series, PC and PA6 of developed country's design, and the air valve valve face of these types all adopts cold-stamped method to improve hardness.
In recent years, because the tempo of main frame is very fast, the pressure in unit load and cylinder obviously improves, and this just has higher requirement to air valve valve face quality.But under certain tonnage, cold extrusion NiCr20TiAl air valve valve face processed case depth can only reach 0.6mm, can not meet design requirement, this just caused the fatigue strength of product and work-ing life not ideal enough.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of method that can effectively increase the diesel engine NiCr20TiAl air valve valve face sclerosis processed of the local hardening degree of depth, to improve fatigue strength and the work-ing life of air valve.
Technical scheme of the present invention is as follows: the method for a kind of diesel engine NiCr20TiAl air valve valve face sclerosis processed, comprises the following steps:
1) preheating: NiCr20TiAl air valve processed is preheated to 280-380 ℃ in pit furnace, and then clamping is on vertical lathe;
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame, heat air valve valve face to 620-650 ℃, then remain on the following heating edge roll extrusion of this temperature, rolling pressure is 30000-38000N, the linear velocity that air valve valve face rotates is 15-25mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.5-1.0Mpa;
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is preheated to 280-380 ℃ in pit furnace, then clamping is on vertical lathe, and air valve is rotated, use again oxygen-acetylene flame heating air valve valve face to 580-610 ℃, then remain on the following heating edge roll extrusion of this temperature, rolling pressure is 40000-53000N, and the linear velocity that air valve valve face rotates is 10-20mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.8-1.2Mpa;
4) heat for the third time roll extrusion: with oxygen-acetylene flame, heat air valve valve face to 550-580 ℃, then remain on the following heating edge roll extrusion of this temperature, rolling pressure is 50000-60000N, and the linear velocity that air valve valve face rotates is 10-20mm/s, roll extrusion is complete, air cooling;
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 510-530 ℃, insulation 5-8 hour, last air cooling is to room temperature.
Above 2), 3), 4) step adopts the milled head of hydro-cylinder to carry out roll extrusion.
Ultimate principle of the present invention is: along with the rising of temperature, the deformation resistance of NiCr20TiAl air valve valve face declines, and under equal pressure-acting, the deformation quantity of part increases, and the deformation degree of depth increases.Deformation quantity and the deformation degree of depth are larger, and austenite crystal distortion is even broken just more serious, and when dislocation desity significantly increases, grain boundary area also increases greatly, and strain-hardening successful improves.After deformation, the fast cold generation that reduces reply phenomenon, makes more polycrystal defect be retained.Timeliness is subsequently conducive to that part internal stress is eliminated and partially carbonized thing, intermetallic compound etc. locate to be particulate state and highly dispersed is separated out in dislocation, crystal boundary, twin boundary, subgrain boundary etc., thereby has guaranteed that strain-hardening effect significantly improves.Vickers' hardness instrumentation hardened layer hardness and the degree of depth for the NiCr20TiAl air valve valve face that the present invention produces, be spaced apart 0.1mm between each measurement point.NiCr20TiAl air valve valve face hardness after aforesaid method is processed can reach 467-524HV, and hardened-depth reaches 2.9-3.3mm.
During due to roll extrusion, air valve is wanted distribute heat, the present invention is in step 2), 3), 4) in portable infrared thermometer, measure the temperature of air valve valve face, according to measured temperature, regulate at any time the size of oxygen-acetylene flame, make the temperature of air valve valve face remain on the required numerical value of roll extrusion, thereby guaranteed the effect of air valve valve face sclerosis.
Beneficial effect: the present invention makes more than diesel engine NiCr20TiAl air valve valve face processed case depth increased 2mm than the identical formed case depth of cold extrusion pressure, the more than three times of cold extrusion case depth, can reach 2.9-3.3mm, the fatigue strength of air valve, work-ing life and reliability are significantly improved.
Embodiment
Below in conjunction with embodiment, the invention will be further described:
Embodiment 1
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be the NiCr20TiAl air valve of φ 112.4mm, the wide 12.8mm of valve face in pit furnace with 340 ℃ of preheatings, be incubated after 90 minutes, clamping is on vertical lathe.
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 650 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 650 ℃ of limit heating edge roll extrusion, rolling pressure is 38000N, and the linear velocity that air valve valve face rotates is 15mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.8Mpa.
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is taken off from vertical machine, put into 300 ℃ of preheatings for pit furnace, insulation insulation is after 90 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 600 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 600 ℃ of limit heating edge roll extrusion, rolling pressure is 47000N, the linear velocity that air valve valve face rotates is 12mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.8Mpa.
4) heat for the third time roll extrusion: with oxygen-acetylene flame heating air valve valve face to 570 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 570 ℃ of limit heating edge roll extrusion, rolling pressure is 56000N, the linear velocity that air valve valve face rotates is 10mm/s, and roll extrusion is complete, and air cooling is to room temperature.
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 520 ℃, be incubated 7 hours, last air cooling is to room temperature.
Above 2), 3), 4) step adopts the milled head of hydro-cylinder to carry out roll extrusion.Air valve after aforesaid method is processed, by hardness gradient method, recording valve face hardness is 478-519HV, case depth is 3.1mm.
Embodiment 2
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be the NiCr20TiAl air valve of φ 89.6mm, the wide 9.7mm of valve face in pit furnace with 330 ℃ of preheatings, be incubated after 70 minutes, clamping is on vertical lathe.
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 630 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 630 ℃ of limit heating edge roll extrusion, rolling pressure is 35000N, and the linear velocity that air valve valve face rotates is 18mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.6Mpa.
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is taken off from vertical machine, put into 290 ℃ of preheatings for pit furnace, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 590 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 590 ℃ of limit heating edge roll extrusion, rolling pressure is 44000N, the linear velocity that air valve valve face rotates is 15mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.6Mpa.
4) heat for the third time roll extrusion: with oxygen-acetylene flame heating air valve valve face to 550 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 550 ℃ of limit heating edge roll extrusion, rolling pressure is 50000N, the linear velocity that air valve valve face rotates is 12mm/s, and roll extrusion is complete, and air cooling is to room temperature.
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 530 ℃, be incubated 5 hours, last air cooling is to room temperature.
Above 2), 3), 4) step adopts the milled head of hydro-cylinder to carry out roll extrusion.Air valve after aforesaid method is processed, by hardness gradient method, recording valve face hardness is 471-513HV, case depth is 2.9mm.
Embodiment 3
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be the NiCr20TiAl air valve of φ 112.4mm, the wide 12.8mm of valve face in pit furnace with 280 ℃ of preheatings, be incubated after 90 minutes, clamping is on vertical lathe.
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 620 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 620 ℃ of limit heating edge roll extrusion, rolling pressure is 30000N, and the linear velocity that air valve valve face rotates is 15mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.5Mpa.
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is taken off from vertical machine, put into 280 ℃ of preheatings for pit furnace, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 580 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 580 ℃ of limit heating edge roll extrusion, rolling pressure is 40000N, the linear velocity that air valve valve face rotates is 10mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.8Mpa.
4) heat for the third time roll extrusion: with oxygen-acetylene flame heating air valve valve face to 550 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 550 ℃ of limit heating edge roll extrusion, rolling pressure is 50000N, the linear velocity that air valve valve face rotates is 10mm/s, and roll extrusion is complete, and air cooling is to room temperature.
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 510 ℃, be incubated 5 hours, last air cooling is to room temperature.
Above 2), 3), 4) step adopts the milled head of hydro-cylinder to carry out roll extrusion.Air valve after aforesaid method is processed, by hardness gradient method, recording valve face hardness is 468-510HV, case depth is 3.0mm.
Embodiment 4
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be the NiCr20TiAl air valve of φ 112.4mm, the wide 12.8mm of valve face in pit furnace with 350 ℃ of preheatings, be incubated after 70 minutes, clamping is on vertical lathe.
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 640 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 640 ℃ of limit heating edge roll extrusion, rolling pressure is 35000N, and the linear velocity that air valve valve face rotates is 20mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.7Mpa.
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is taken off from vertical machine, put into 330 ℃ of preheatings for pit furnace, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 600 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 600 ℃ of limit heating edge roll extrusion, rolling pressure is 46000N, the linear velocity that air valve valve face rotates is 15mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 1.0Mpa.
4) heat for the third time roll extrusion: with oxygen-acetylene flame heating air valve valve face to 560 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 560 ℃ of limit heating edge roll extrusion, rolling pressure is 55000N, the linear velocity that air valve valve face rotates is 15mm/s, and roll extrusion is complete, and air cooling is to room temperature.
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 520 ℃, be incubated 6 hours, last air cooling is to room temperature.
Above 2), 3), 4) step adopts the milled head of hydro-cylinder to carry out roll extrusion.Air valve after aforesaid method is processed, by hardness gradient method, recording valve face hardness is 475-515HV, case depth is 3.2mm.
Embodiment 5
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be the NiCr20TiAl air valve of φ 89.6mm, the wide 9.7mm of valve face in pit furnace with 380 ℃ of preheatings, be incubated after 90 minutes, clamping is on vertical lathe.
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 650 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 650 ℃ of limit heating edge roll extrusion, rolling pressure is 38000N, and the linear velocity that air valve valve face rotates is 25mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 1.0Mpa.
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is taken off from vertical machine, put into 370 ℃ of preheatings for pit furnace, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 610 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 610 ℃ of limit heating edge roll extrusion, rolling pressure is 53000N, the linear velocity that air valve valve face rotates is 20mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 1.2Mpa.
4) heat for the third time roll extrusion: with oxygen-acetylene flame heating air valve valve face to 580 ℃, with portable infrared thermometer, measure the temperature of air valve valve face, to regulate the size of oxygen-acetylene, make air valve remain on 580 ℃ of limit heating edge roll extrusion, rolling pressure is 60000N, the linear velocity that air valve valve face rotates is 20mm/s, and roll extrusion is complete, and air cooling is to room temperature.
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 530 ℃, be incubated 8 hours, last air cooling is to room temperature.
Above 2), 3), 4) step adopts the milled head of hydro-cylinder to carry out roll extrusion.Air valve after aforesaid method is processed, by hardness gradient method, recording valve face hardness is 478-524HV, case depth is 3.3mm.
Claims (2)
1. the method that diesel engine NiCr20TiAl air valve valve face processed hardens, is characterized in that comprising the following steps:
1) preheating: NiCr20TiAl air valve processed is preheated to 280-380 ℃ in pit furnace, and then clamping is on vertical lathe;
2) heat for the first time roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame, heat air valve valve face to 620-650 ℃, then remain on the following heating edge roll extrusion of this temperature, rolling pressure is 30000-38000N, the linear velocity that air valve valve face rotates is 15-25mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.5-1.0Mpa;
3) preheating is also heated roll extrusion for the second time again: the air valve heating for the first time after roll extrusion is preheated to 280-380 ℃ in pit furnace, then clamping is on vertical lathe, and air valve is rotated, use again oxygen-acetylene flame heating air valve valve face to 580-610 ℃, then remain on the following heating edge roll extrusion of this temperature, rolling pressure is 40000-53000N, and the linear velocity that air valve valve face rotates is 10-20mm/s, simultaneously that the position of the own roll extrusion of air valve valve face is cooling by the air for continuous of 0.8-1.2Mpa;
4) heat for the third time roll extrusion: with oxygen-acetylene flame, heat air valve valve face to 550-580 ℃, then remain on the following heating edge roll extrusion of this temperature, rolling pressure is 50000-60000N, and the linear velocity that air valve valve face rotates is 10-20mm/s, roll extrusion is complete, air cooling;
5) ageing treatment: air valve is taken off from vertical lathe, then put into pit furnace and carry out ageing treatment with 510-530 ℃, insulation 5-8 hour, last air cooling is to room temperature.
2. the method that diesel engine NiCr20TiAl according to claim 1 air valve valve face processed hardens, it is characterized in that: in step 2), 3), 4) in portable infrared thermometer, measure the temperature of air valve valve face, the size that regulates oxygen-acetylene flame according to measured temperature, makes the temperature of air valve valve face remain on the required numerical value of roll extrusion.
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| CN201310654462.0A CN103614526B (en) | 2013-12-05 | 2013-12-05 | Method for hardening valve surface of gas valve of diesel engine |
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| CN201310654462.0A CN103614526B (en) | 2013-12-05 | 2013-12-05 | Method for hardening valve surface of gas valve of diesel engine |
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| CN103614526B CN103614526B (en) | 2015-07-15 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180043434A1 (en) * | 2015-04-23 | 2018-02-15 | The Timken Company | Method of forming a component |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5873718A (en) * | 1981-10-26 | 1983-05-04 | Kobe Steel Ltd | Manufacture of steel material for high-silicon spring |
| CN101089203A (en) * | 2006-06-12 | 2007-12-19 | 何才田 | Hardening technology for surface alloy of gas valve of high power diesel engine |
| CN101210276A (en) * | 2007-12-21 | 2008-07-02 | 沪东重机有限公司 | Rolling method for exhaust valve surface |
| CN102000952A (en) * | 2010-11-11 | 2011-04-06 | 重庆跃进机械厂有限公司 | Processing method of sealing surface of exhaust valve of low-speed diesel engine |
| CN103161541A (en) * | 2011-12-15 | 2013-06-19 | 上海潘丰机电设备有限公司 | Diesel engine air valve and hardening process thereof |
-
2013
- 2013-12-05 CN CN201310654462.0A patent/CN103614526B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5873718A (en) * | 1981-10-26 | 1983-05-04 | Kobe Steel Ltd | Manufacture of steel material for high-silicon spring |
| CN101089203A (en) * | 2006-06-12 | 2007-12-19 | 何才田 | Hardening technology for surface alloy of gas valve of high power diesel engine |
| CN101210276A (en) * | 2007-12-21 | 2008-07-02 | 沪东重机有限公司 | Rolling method for exhaust valve surface |
| CN102000952A (en) * | 2010-11-11 | 2011-04-06 | 重庆跃进机械厂有限公司 | Processing method of sealing surface of exhaust valve of low-speed diesel engine |
| CN103161541A (en) * | 2011-12-15 | 2013-06-19 | 上海潘丰机电设备有限公司 | Diesel engine air valve and hardening process thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20180043434A1 (en) * | 2015-04-23 | 2018-02-15 | The Timken Company | Method of forming a component |
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