Rolling method for exhaust valve surface

A technology of exhaust valve and valve face, which is applied in the field of rolling, can solve the problems of low hardness of the valve face and short service life, and achieve the effect of extending the overhaul period and improving the service life

Inactive Publication Date: 2008-07-02
HUDONG HEAVY MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the shortcomings of low valve surface hardness and short service life caused by the above-mentioned common process for rolling the valve surface of the exhaust valve, and provide a method for rolling the valve surface of the exhaust valve. It is an operation process specially prepared for the hardening of the valve surface of the exhaust valve. It breaks the limitation of the small improvement of the surface hardening hardness of the parts in the past, and greatly improves the hardness of the valve surface of the exhaust valve of the diesel engine, reaching or exceeding the application hardness value.

Method used

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  • Rolling method for exhaust valve surface

Examples

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Effect test

Embodiment 1

[0029] When the material of the valve surface of the exhaust valve is NiCr18Fe18Nb alloy, the specific steps of the rolling method for the valve surface of the exhaust valve are as follows:

[0030] Fix the exhaust valve on the turntable of the rolling device, and then press the roller near the valve surface of the exhaust valve, and the surface of the roller is coated with molybdenum disulfide as a lubricant;

[0031] Align the roller of the rolling device with the inner side of the valve surface, and then apply pressure to the valve surface through the roller. The pressure application process is a fixed pressure within a set period of time, and the pressure increases stepwise with each step. , in this embodiment, the hydraulic system is used to apply pressure to the rollers, and the load is increased by 2 tons every 30 seconds, and the final load is 8 tons. The pressure applied on the valve surface increases from 0 tons to 2 tons; in the second 30 seconds, the hydraulic syst...

Embodiment 2

[0035] When the material of the valve surface of the exhaust valve is NiCr18Co12Nb alloy, the specific steps of the rolling method for the valve surface of the exhaust valve are as follows:

[0036] Fix the exhaust valve on the turntable of the rolling device, and then press the roller near the valve surface of the exhaust valve, and the surface of the roller is coated with tallow as a lubricant;

[0037] Align the roller of the rolling device with the inner side of the valve surface, and then apply pressure to the valve surface through the roller. The pressure application process is a fixed pressure within a set period of time, and the pressure increases stepwise with each step. , in the present embodiment, the hydraulic system is used to apply pressure to the roller, and the load is increased by 2 tons every 30 seconds, and the final load is 10 tons;

[0038] After rolling out the first groove with a depth of 2.2mm on the valve surface, loosen the roller, and then continue t...

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Abstract

The invention relates to a surface rolling method for vent valves, which comprises the following steps of: fixing a vent valve on the rotary disk of a rolling device, pressing rollers on the surface of the vent valve, and applying pressure on the valve surface by the rollers during rotation process of the vent valve, wherein the pressure application step includes the steps of: aligning the rollers of the rolling device to the inner side of the valve surface, and applying pressure on the valve surface by the rollers in such a process of increasing pressure, holding pressure, increasing pressure, holding pressure,ellipsis, until reaching a maximal pressure; the pressure is generally increased in stepwise; a first groove with a certain depth is formed on the valve surface, and then the rollers are loosened, move to the outer side of the first groove and further roll the valve surface to form a plurality of other grooves; finally, the valve surface with the plurality of grooves provided thereon are processed to remove the margin. According to the invention, the surface hardness of the vent valve can be improved by 80 to 110 HV in comparison with the common rolling method, thus improving the service life of the vent valve by 1 to 3 times.

Description

technical field [0001] The invention relates to rolling technology, in particular to a method for rolling on the valve surface of an exhaust valve to enhance the hardness of the valve surface. Background technique [0002] In order to improve the service life and safe operation of the exhaust valve of low-speed diesel engine, it is necessary to surfacing hard alloy on the valve surface of the exhaust valve to increase the hardness of the valve surface. However, the required hardness cannot be achieved only after surfacing of cemented carbide, so certain measures are taken to harden the surfacing of cemented carbide. [0003] There are several methods of surface hardening a part, the most common being work hardening. That is, in the cold plastic deformation of the metal, the strength index of the metal, such as the yield point and hardness, is increased, and the plastic index such as the elongation is reduced. Examples of the use of this process are: sandblasting (increasin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D7/04
Inventor 周伟中杜惊霄姚火珍
Owner HUDONG HEAVY MACHINERY
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