阅读说明：本技术 一种直升机用自润滑铜基粉末冶金结构件的制备方法 (Preparation method of self-lubricating copper-based powder metallurgy structural part for helicopter ) 是由 周训伟 巢昺轩 项洪涛 郭楠 李智勇 熊曦耀 应俊龙 李岚 刘小丹 于 2020-11-20 设计创作，主要内容包括：本发明提供一种直升机用自润滑铜基粉末冶金结构件的制备方法,包括：步骤一、根据结构件需求选用铜金属粉末、锡金属粉末、石墨和石蜡；步骤二、将铜、锡金属粉末与石墨、石蜡进行充分、均匀混合,得到均匀混合后的粉末；步骤三、将均匀混合后的粉末采用冷等静压压制成生坯,并置于H-2保护气氛进行烧结。通过添加石墨,能够提高该结构件的自润滑性能；添加石蜡,可保证密度相差较大的石墨与铜、锡金属粉末均匀混合,能够消除密度差带来成分偏析的影响,满足密度要求。(The invention provides a preparation method of a self-lubricating copper-based powder metallurgy structural part for a helicopter, which comprises the following steps: selecting copper metal powder, tin metal powder, graphite and paraffin according to the requirements of a structural part; fully and uniformly mixing copper and tin metal powder with graphite and paraffin to obtain uniformly mixed powder; step three, pressing the uniformly mixed powder into a green body by adopting cold isostatic pressing, and placing the green body in H 2 Sintering in a protective atmosphere. By adding graphite, the self-lubricating property of the structural part can be improved; the paraffin is added, so that the graphite with larger density phase difference can be uniformly mixed with the copper and tin metal powder, and the influence of component segregation caused by the density difference can be eliminatedAnd the density requirement is met.)

1. A preparation method of a self-lubricating copper-based powder metallurgy structural part for a helicopter is characterized by comprising the following steps:

selecting copper metal powder, tin metal powder, graphite and paraffin according to the requirements of a structural part;

fully and uniformly mixing copper and tin metal powder with graphite and paraffin to obtain uniformly mixed powder;

step three, pressing the uniformly mixed powder into a green body by adopting cold isostatic pressing, and placing the green body in H₂Sintering in a protective atmosphere.

2. The method of claim 1, wherein selecting copper metal powder, tin metal powder, graphite, and paraffin according to the structural requirements comprises:

and proportioning the copper metal powder, the tin metal powder and the graphite according to the chemical component requirements of the structural component.

3. The method according to claim 2, wherein the paraffin ratio is not more than 2%.

4. The method of claim 3, wherein the mixing the copper and tin metal powders with the graphite and paraffin wax is performed fully and uniformly, and comprises:

fully and uniformly mixing copper and tin metal powder, graphite and paraffin wax through grinding equipment.

5. The method of claim 4, wherein prior to the intimate and homogeneous mixing of the copper and tin metal powders with the graphite and paraffin wax, the method further comprises:

and drying the tin metal powder and the graphite at a low temperature, and carrying out annealing heat treatment on the copper powder.

6. The method of claim 5, wherein the cold isostatic pressing of the uniformly mixed powder into a green body comprises:

and pressing the uniformly mixed powder into a green body by adopting cold isostatic pressing under 220 MPa.

7. The method of claim 6, wherein the sintering process parameters comprise: the heating rate of the sintering equipment is 10-20 ℃/min, the sintering temperature is 800-850 ℃, and the heat preservation time is not less than 1 h.

8. The method of claim 7, wherein the placing H is performed by₂After sintering in the protective atmosphere, the method further comprises:

cooling the mixture to a preset temperature along with the furnace, and then air cooling the mixture;

the preset temperature is lower than the sintering temperature.

Technical Field

The invention belongs to the field of powder metallurgy, and relates to a preparation method of a self-lubricating copper-based powder metallurgy structural member for a helicopter.

Background

The helicopter control system comprises an automatic inclinometer, and is mainly used for realizing the control of the total pitch and the periodic pitch variation of a rotor wing, and further realizing the motions of lifting, front-back, left-right and the like of the helicopter.

The realization of the function of the automatic inclinometer requires that a structural part with a lubricating function is arranged in an assembly component of the automatic inclinometer. The original structural member with the lubricating function belongs to the form of aluminum alloy lining, and the service life of the structural member does not meet the requirement.

Disclosure of Invention

The invention provides a preparation method of a self-lubricating copper-based powder metallurgy structural member for a helicopter.

The invention provides a preparation method of a self-lubricating copper-based powder metallurgy structural part for a helicopter, which comprises the following steps:

selecting copper metal powder, tin metal powder, graphite and paraffin according to the requirements of a structural part;

fully and uniformly mixing copper and tin metal powder with graphite and paraffin to obtain uniformly mixed powder;

step three, pressing the uniformly mixed powder into a green body by adopting cold isostatic pressing, and placing the green body in H₂Sintering in a protective atmosphere.

Optionally, select for use copper metal powder, tin metal powder, graphite and paraffin according to the structure demand, include:

and proportioning the copper metal powder, the tin metal powder and the graphite according to the chemical component requirements of the structural component.

Optionally, the ratio of the paraffin is not more than 2%.

Optionally, the metal powder of copper and tin, graphite and paraffin are fully and uniformly mixed, including:

fully and uniformly mixing copper and tin metal powder, graphite and paraffin wax through grinding equipment.

Optionally, before the copper and tin metal powders are fully and uniformly mixed with the graphite and the paraffin, the method further includes:

and drying the tin metal powder and the graphite at a low temperature, and carrying out annealing heat treatment on the copper powder.

Optionally, the pressing the uniformly mixed powder into a green body by using isostatic cool pressing includes:

and pressing the uniformly mixed powder into a green body by adopting cold isostatic pressing under 220 MPa.

Optionally, the sintering process parameters include: the heating rate of the sintering equipment is 10-20 ℃/min, the sintering temperature is 800-850 ℃, and the heat preservation time is not less than 1 h.

Optionally, the placing in H₂After sintering in the protective atmosphere, the method further comprises:

cooling the mixture to a preset temperature along with the furnace, and then air cooling the mixture;

the preset temperature is lower than the sintering temperature.

The invention provides a preparation method of a self-lubricating copper-based powder metallurgy structural member for a helicopter. The graphite is added, so that the self-lubricating property of the structural part can be improved; paraffin is added as an adhesive, so that the graphite with large density phase difference can be uniformly mixed with copper and tin metal powder, and the influence of component segregation caused by the density difference can be eliminated; during the sintering process, paraffin is melted and volatilized, and certain pores can be formed in the sintered part during the volatilization process, so that the density requirement is met; finally, through performance detection of density, tensile strength, hardness, metallographic phase, linear expansion coefficient and the like, the external dimension and various performance indexes of the material meet the design and use requirements.

Drawings

Fig. 1 is a schematic flow chart of a preparation method of the self-lubricating copper-based powder metallurgy structural member for the helicopter provided by the invention.

Detailed Description

The following explains the preparation method of the self-lubricating copper-based powder metallurgy structural member for the helicopter provided by the invention with reference to the accompanying drawings.

The invention aims to prepare a graphite-containing tin bronze sintered part with a self-lubricating function, a density of 6.5-7.1 g/cm3, a tensile strength sigma b of more than or equal to 92MPa and a powder metallurgy process. The self-inclining instrument assembly component is used as a self-inclining instrument assembly component of a helicopter so as to ensure that the function of the self-inclining instrument is smoothly realized.

According to the invention, a certain amount of graphite and paraffin are added into copper and tin metal powder, the mixture is uniformly mixed and then is subjected to compression molding, and then sintering is performed in a protective atmosphere, so that the copper-based powder metallurgy structural member with comprehensive performance meeting the use requirement is realized. According to the invention, the graphite is added, so that the self-lubricating property of the structural component can be improved; paraffin is added as an adhesive, so that the graphite with large density phase difference can be uniformly mixed with copper and tin metal powder, and the influence of component segregation caused by the density difference can be eliminated; during the sintering process, paraffin is melted and volatilized, and certain pores can be formed in the sintered part during the volatilization process, so that the density requirement is met; finally, through performance detection of density, tensile strength, hardness, metallographic phase, linear expansion coefficient and the like, the external dimension and various performance indexes of the material meet the design and use requirements.

Fig. 1 is a schematic flow chart of a method for preparing a self-lubricating copper-based powder metallurgy structural member for a helicopter, according to fig. 1, the method for preparing a self-lubricating copper-based powder metallurgy structural member for a helicopter, provided by the invention, comprises the following steps:

1) selecting copper metal powder, tin metal powder, graphite and paraffin according to chemical component requirements;

2) drying tin metal powder and graphite at low temperature, and carrying out annealing heat treatment on copper powder;

3) fully and uniformly mixing copper and tin metal powder, graphite and paraffin to obtain uniformly mixed powder, wherein the ratio of the paraffin is not more than 2%;

4) pressing the uniformly mixed powder into a green body by adopting isostatic cool pressing, and placing the green body in H₂Sintering in a protective atmosphere. The heating rate of the sintering equipment is 10-20 ℃/min, the sintering temperature is 800-850 ℃, the heat preservation time is not less than 1h, the sintering equipment is cooled to a lower temperature along with the furnace after sintering, and then air cooling is carried out.

The method provided by the invention is described below with reference to specific examples.

In a specific example, the copper and tin metal powders and graphite are proportioned according to the chemical composition of Cu87.5%, Sn9.5%, C2.0% and impurity element 1%. For the powder size requirement below 45 μm, the copper powder is about 70%, the tin is about 90%, and the graphite is 100%. 2% paraffin wax was added. Fully mixing the raw materials by grinding equipment, performing cold isostatic pressing at 220MPa to form a green body, and performing H₂Sintering in a protective atmosphere. The sintering process parameters are as follows: the temperature rising rate of the sintering furnace is 20 ℃/min, the sintering temperature is 810 ℃, and the temperature is kept for 1 h. And cooling the sintered copper base powder to 300 ℃ along with the furnace, and then air cooling to obtain the self-lubricating copper base powder metallurgy structural member.