CN103614526B - 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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- CN103614526B CN103614526B CN201310654462.0A CN201310654462A CN103614526B CN 103614526 B CN103614526 B CN 103614526B CN 201310654462 A CN201310654462 A CN 201310654462A CN 103614526 B CN103614526 B CN 103614526B
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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 for particularly a kind of diesel engine NiCr20TiAl air valve valve face sclerosis.
Background technology
NiCr20TiAl air valve 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 determining diesel engine performance and reliability.
Based on part, it plays a very important role diesel engine.
Air valve in use lost efficacy, and will directly produce the serious consequence such as distortion or damage of the component such as main frame cylinder, piston, supercharging blower.
Because air valve is running stores, occupy heart, when change, 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 caused will be larger.
In order to improve the wear resistance of air valve valve face, fatigue strength and work-ing life, China introduces the types such as the DK machine series of developed country's design, PC and PA6, 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 significantly improves, and this just has higher requirement to air valve valve face quality.But under certain tonnage, cold extrusion NiCr20TiAl air valve valve face case depth can only reach 0.6mm, can not meet design requirement, this just cause 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 effectively can increase the diesel engine NiCr20TiAl air valve valve face sclerosis 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: a kind of method of diesel engine NiCr20TiAl air valve valve face sclerosis, comprises the following steps:
1) preheating: NiCr20TiAl air valve is preheated to 280-380 DEG C in pit furnace, and then clamping is on vertical lathe;
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 620-650 DEG C, then the following heating edge roll extrusion of this temperature is remained on, rolling pressure is 30000-38000N, the linear velocity that air valve valve face rotates is 15-25mm/s, the air for continuous of the position 0.5-1.0Mpa of own for air valve valve face roll extrusion is cooled simultaneously;
3) preheating also heats roll extrusion for the second time again: the air valve after first time heating roll extrusion is preheated to 280-380 DEG C in pit furnace, then clamping is on vertical lathe, and air valve is rotated, use oxygen-acetylene flame heating air valve valve face to 580-610 DEG C again, then the following heating edge roll extrusion of this temperature is remained on, rolling pressure is 40000-53000N, and the linear velocity that air valve valve face rotates is 10-20mm/s, the air for continuous of the position 0.8-1.2Mpa of own for air valve valve face roll extrusion is cooled simultaneously;
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 550-580 DEG C, 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: taken off from vertical lathe by air valve, then puts into pit furnace 510-530 DEG C and carries out ageing treatment, and 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, and the deformation resistance of NiCr20TiAl air valve valve face declines, and under same equipressure effect, the deformation quantity of part increases, and the deformation degree of depth increases.Deformation quantity and the deformation degree of depth larger, austenite crystal distortion is even broken more serious, and while dislocation desity significantly increases, grain boundary area also increases greatly, the raising of strain-hardening successful.After deformation, rapid cooling can reduce the generation of reply phenomenon, makes more polycrystal defect be retained.Timeliness is subsequently conducive to the elimination of part internal stress and partially carbonized thing, intermetallic compound etc. are particulate state at places such as dislocation, crystal boundary, twin boundary, subgrain boundaries and highly dispersed is separated out, thus ensure that strain-hardening Be very effective improves.The NiCr20TiAl air valve valve face that the present invention produces Vickers' hardness measurement hardened layer hardness and the degree of depth, is spaced apart 0.1mm between each measurement point.NiCr20TiAl air valve valve face hardness after aforesaid method process can reach 467-524HV, and hardened-depth reaches 2.9-3.3mm.
Because air valve during roll extrusion wants distribute heat, the present invention is in step 2), 3), 4) in measure the temperature of air valve valve face with portable infrared thermometer, the size of oxygen-acetylene flame is regulated at any time according to measured temperature, make the temperature of air valve valve face remain on numerical value needed for roll extrusion, thus ensure that the effect that air valve valve face hardens.
Beneficial effect: the case depth that the present invention makes diesel engine NiCr20TiAl air valve valve face case depth be formed than identical cold extrusion pressure adds more than 2mm, it is 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 φ 112.4mm, the wide 12.8mm of valve face NiCr20TiAl air valve in pit furnace with 340 DEG C of preheatings, be incubated after 90 minutes, clamping is on vertical lathe.
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 650 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 650 DEG C of limit heating edge roll extrusion, rolling pressure is 38000N, and the linear velocity that air valve valve face rotates is 15mm/s, the air for continuous of the position 0.8Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
3) preheating also heats roll extrusion for the second time again: taken off from vertical machine by the air valve after first time heating roll extrusion, put into pit furnace 300 DEG C of preheatings, insulation insulation is after 90 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 600 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 600 DEG C of limit heating edge roll extrusion, rolling pressure is 47000N, the linear velocity that air valve valve face rotates is 12mm/s, the air for continuous of the position 0.8Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 570 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 570 DEG C 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: taken off from vertical lathe by air valve, then puts into pit furnace and carries out ageing treatment with 520 DEG C, and 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 process, recording valve face hardness by hardness gradient method is 478-519HV, and case depth is 3.1mm.
Embodiment 2
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be φ 89.6mm, the wide 9.7mm of valve face NiCr20TiAl air valve in pit furnace with 330 DEG C of preheatings, be incubated after 70 minutes, clamping is on vertical lathe.
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 630 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 630 DEG C of limit heating edge roll extrusion, rolling pressure is 35000N, and the linear velocity that air valve valve face rotates is 18mm/s, the air for continuous of the position 0.6Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
3) preheating also heats roll extrusion for the second time again: taken off from vertical machine by the air valve after first time heating roll extrusion, put into pit furnace 290 DEG C of preheatings, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 590 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 590 DEG C of limit heating edge roll extrusion, rolling pressure is 44000N, the linear velocity that air valve valve face rotates is 15mm/s, the air for continuous of the position 0.6Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 550 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 550 DEG C 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: taken off from vertical lathe by air valve, then puts into pit furnace and carries out ageing treatment with 530 DEG C, and 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 process, recording valve face hardness by hardness gradient method is 471-513HV, and case depth is 2.9mm.
Embodiment 3
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be φ 112.4mm, the wide 12.8mm of valve face NiCr20TiAl air valve in pit furnace with 280 DEG C of preheatings, be incubated after 90 minutes, clamping is on vertical lathe.
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 620 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 620 DEG C of limit heating edge roll extrusion, rolling pressure is 30000N, and the linear velocity that air valve valve face rotates is 15mm/s, the air for continuous of the position 0.5Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
3) preheating also heats roll extrusion for the second time again: taken off from vertical machine by the air valve after first time heating roll extrusion, put into pit furnace 280 DEG C of preheatings, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 580 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 580 DEG C of limit heating edge roll extrusion, rolling pressure is 40000N, the linear velocity that air valve valve face rotates is 10mm/s, the air for continuous of the position 0.8Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 550 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 550 DEG C 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: taken off from vertical lathe by air valve, then puts into pit furnace and carries out ageing treatment with 510 DEG C, and 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 process, recording valve face hardness by hardness gradient method is 468-510HV, and case depth is 3.0mm.
Embodiment 4
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be φ 112.4mm, the wide 12.8mm of valve face NiCr20TiAl air valve in pit furnace with 350 DEG C of preheatings, be incubated after 70 minutes, clamping is on vertical lathe.
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 640 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 640 DEG C of limit heating edge roll extrusion, rolling pressure is 35000N, and the linear velocity that air valve valve face rotates is 20mm/s, the air for continuous of the position 0.7Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
3) preheating also heats roll extrusion for the second time again: taken off from vertical machine by the air valve after first time heating roll extrusion, put into pit furnace 330 DEG C of preheatings, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 600 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 600 DEG C of limit heating edge roll extrusion, rolling pressure is 46000N, the linear velocity that air valve valve face rotates is 15mm/s, the air for continuous of the position 1.0Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 560 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 560 DEG C 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: taken off from vertical lathe by air valve, then puts into pit furnace and carries out ageing treatment with 520 DEG C, and 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 process, recording valve face hardness by hardness gradient method is 475-515HV, and case depth is 3.2mm.
Embodiment 5
The present embodiment comprises the following steps:
1) preheating: by valve disc diameter be φ 89.6mm, the wide 9.7mm of valve face NiCr20TiAl air valve in pit furnace with 380 DEG C of preheatings, be incubated after 90 minutes, clamping is on vertical lathe.
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 650 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 650 DEG C of limit heating edge roll extrusion, rolling pressure is 38000N, and the linear velocity that air valve valve face rotates is 25mm/s, the air for continuous of the position 1.0Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
3) preheating also heats roll extrusion for the second time again: taken off from vertical machine by the air valve after first time heating roll extrusion, put into pit furnace 370 DEG C of preheatings, insulation insulation is after 80 minutes, and clamping is on vertical lathe again; With oxygen-acetylene flame heating air valve valve face to 610 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 610 DEG C of limit heating edge roll extrusion, rolling pressure is 53000N, the linear velocity that air valve valve face rotates is 20mm/s, the air for continuous of the position 1.2Mpa of own for air valve valve face roll extrusion is cooled simultaneously.
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 580 DEG C, the temperature of air valve valve face is measured with portable infrared thermometer, to regulate the size of oxygen-acetylene, air valve is made to remain on 580 DEG C 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: taken off from vertical lathe by air valve, then puts into pit furnace and carries out ageing treatment with 530 DEG C, and 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 process, recording valve face hardness by hardness gradient method is 478-524HV, and case depth is 3.3mm.
Claims (2)
1. a method for diesel engine NiCr20TiAl air valve valve face sclerosis, is characterized in that comprising the following steps:
1) preheating: NiCr20TiAl air valve is preheated to 280-380 DEG C in pit furnace, and then clamping is on vertical lathe;
2) first time heats roll extrusion: air valve rotates on vertical lathe, with oxygen-acetylene flame heating air valve valve face to 620-650 DEG C, then the following heating edge roll extrusion of this temperature is remained on, rolling pressure is 30000-38000N, the linear velocity that air valve valve face rotates is 15-25mm/s, the air for continuous of the position 0.5-1.0Mpa of own for air valve valve face roll extrusion is cooled simultaneously;
3) preheating also heats roll extrusion for the second time again: the air valve after first time heating roll extrusion is preheated to 280-380 DEG C in pit furnace, then clamping is on vertical lathe, and air valve is rotated, use oxygen-acetylene flame heating air valve valve face to 580-610 DEG C again, then the following heating edge roll extrusion of this temperature is remained on, rolling pressure is 40000-53000N, and the linear velocity that air valve valve face rotates is 10-20mm/s, the air for continuous of the position 0.8-1.2Mpa of own for air valve valve face roll extrusion is cooled simultaneously;
4) third time heats roll extrusion: with oxygen-acetylene flame heating air valve valve face to 550-580 DEG C, 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: taken off from vertical lathe by air valve, then puts into pit furnace 510-530 DEG C and carries out ageing treatment, and insulation 5-8 hour, last air cooling is to room temperature.
2. the method for diesel engine NiCr20TiAl air valve valve face sclerosis according to claim 1, it is characterized in that: in step 2), 3), 4) in measure the temperature of air valve valve face with portable infrared thermometer, regulate the size of oxygen-acetylene flame according to measured temperature, make the temperature of air valve valve face remain on numerical value needed for roll extrusion.
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| Application Number | Priority Date | Filing Date | Title |
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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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| CN103614526A CN103614526A (en) | 2014-03-05 |
| CN103614526B true CN103614526B (en) | 2015-07-15 |
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| 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 |
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