Method for preparing engine valve seat through powder metallurgy

An engine valve and powder metallurgy technology, which is applied in the field of auto parts manufacturing, can solve the problems of cracks, time-consuming and resource-consuming, insufficient impact toughness, wear resistance and compressive strength of valve seats, etc. The effect of promoting the application

Inactive Publication Date: 2016-11-09
WEIHAI SHUANGXIN METAL PRODS
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the higher porosity of the valve seat manufactured by powder metallurgy compared with the cast valve seat, this makes the impact toughness, wear resistance and compressive strength of the valve seat have insufficient performance. Disadvantages, for this reason, inspired by the heat treatment process, those skilled in the art heat-treated the valve seat manufactured by powder metallurgy. Practice has proved that the mechanical properties and mechanical properties of the powder metallurgy valve seat after heat treatment have been significantly improved. Heat treatment of the valve seat is feasible
[0003] Due to the large number of powder metallurgy valve seat alloy components, the metallurgical reactions and diffusion of alloy elements that occur during sintering and steam treatment are quite complicated, and the research is very time-consuming and resource-consuming. At the same time, for powder metallurgy valve seats with different alloy components , the heat treatment process is also different, any performance parameter of the valve seat will affect the formulation of the heat treatment process parameters, for example, if the porosity of the valve seat exceeds 10%, when using a salt bath furnace, the molten salt will penetrate into the pores The valve seat is corroded, and the valve seat is scrapped. For example, due to the existence of porosity, the relative density distribution of the valve seat is uneven. During quenching, under various stresses, the valve seat is easily deformed and stress cracks , so the selection of process parameters is very important when heat treating the valve seat.

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  • Method for preparing engine valve seat through powder metallurgy

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Embodiment

[0024] A method for preparing an engine valve seat by powder metallurgy, comprising the following steps:

[0025] Step 1, the raw materials are mixed, respectively take graphite by mass as 2.2%, chromium powder as 1.4%, cobalt powder as 4.5%, aluminum powder as 1.8%, silicon powder as 1.77%, zirconium powder as 0.6%, niobium powder 1.36% hafnium powder, 0.18% hafnium powder, 4.8% additives, and the balance is iron powder, wherein the iron powder is atomized iron powder with a particle size of 100-130 μm, chromium powder, cobalt powder, aluminum powder, The particle size of bismuth powder, silicon powder, zirconium powder, niobium powder and hafnium powder is 75-100 μm, the lubricant is nickel-coated molybdenum disulfide, the graphite is flake graphite with a particle size of 55-75 μm, and the additives are composed of the following mass percentages Made of raw materials: 65% of lubricant, 18% of nano-scale titanium dioxide and 17% of zinc oxide, the above components are placed...

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Abstract

The invention discloses a method for preparing an engine valve seat through powder metallurgy. According to the powder metallurgy valve seat prepared through the preparation method and having specific components, apart from the gain effect brought about by alloying elements, all properties of the powder metallurgy valve seat can be improved obviously, tensile strength of the manufactured valve seat reaches 1260MPa, radial crushing strength reaches 914MPa, Rockwell hardness reaches 69HRC, toughness reaches 8.5MPa.m1 / 2, density of the valve seat reaches 98.7%, and the valve seat is superior to a powder metallurgy valve seat prepared by an existing preparation process. Meanwhile, the expensive copper infiltration process is omitted in the method, manufacturing cost is reduced obviously, and thus the method is easy to apply and popularize.

Description

technical field [0001] The invention belongs to the field of auto parts manufacturing, in particular to a method for preparing an engine valve seat by powder metallurgy. Background technique [0002] As a method of manufacturing auto parts with simple technology, low production cost and good product performance, powder metallurgy technology is widely used in the automobile manufacturing industry. It is material mixing-pressing-sintering-steaming-oil immersion. This process not only enables the combination of non-metallic substances that are difficult to obtain in general molten steel, but also reduces cutting, low material consumption and high production efficiency. However, due to the higher porosity of the valve seat manufactured by powder metallurgy compared with the cast valve seat, this makes the impact toughness, wear resistance and compressive strength of the valve seat have insufficient performance. Disadvantages, for this reason, inspired by the heat treatment proc...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): B22F5/00B22F1/00B22F3/10B22F3/24B22F3/26
CPCB22F3/1007B22F3/24B22F3/26B22F5/00B22F2003/248B22F2999/00B22F2998/10B22F1/10B22F2201/20B22F2201/11B22F3/02B22F2009/043
Inventor张荣斌
OwnerWEIHAI SHUANGXIN METAL PRODS