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Method for improving strength of metal member connection hole

A technology of metal components and connecting holes, applied in the field of material processing

Inactive Publication Date: 2012-07-11
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003]The purpose of the present invention is to provide a method for improving the strength of the connecting hole of the metal component, so as to solve the problem that the metal component is easily damaged in the form of tripping, tearing, etc. Thereby greatly improving the life of components and reducing the occurrence of accidents

Method used

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  • Method for improving strength of metal member connection hole
  • Method for improving strength of metal member connection hole
  • Method for improving strength of metal member connection hole

Examples

Experimental program
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Effect test

Embodiment 1

[0021] like figure 1 , figure 2 Shown is a complex-shaped aluminum alloy casting produced by a certain unit, and the material is ZAlSi 7 Mg1A. For further machining, holes and bolts need to be drilled on the four ledges. Due to the coarse structure of cast aluminum alloy, low mechanical properties, and poor processability, gaps are prone to appear on the thread during processing; damage often occurs here during service, resulting in failure of parts. We first design a reasonable installation fixture and lead-out plate structure according to the shape of the casting (see image 3 ), use the fixture to fix the aluminum alloy casting on the working platform, and then use the process parameters of 2000 rpm and 400 mm / min to carry out friction stir processing strengthening treatment on the four columnar zones of the part, the depth of the processing zone is 15mm, the process is as Figure 4~6 shown. After friction stir processing, the elongation rate increases by 300%, the ...

Embodiment 2

[0023] A large-scale aluminum alloy casting is made of A356 aluminum alloy. Because it is a casting, its structure is coarse, and it contains coarse eutectic Si dendrite structure and fishbone-like Mg. 2 The strength, toughness and fatigue properties of Si, iron-containing phases and shrinkage cavities are affected by the content and size of shrinkage cavities, the shape and size of eutectic Si particles, and the degree of uniform distribution. Fatigue cracks are prone to appear at the light hole and thus make the part fail. After fixing it on the working platform, friction stir processing was carried out under the conditions of rotating speed 1500 rpm, traveling speed 300 mm / min, and lap rate 50%. After processing, the grains in this area were refined, and the aluminum branches The crystal is broken, the coarse acicular Si phase is broken and evenly distributed, the tensile strength and elongation of the processing area are respectively increased by 80% and 600% compared with...

Embodiment 3

[0025] A frame structure, cast from AZ91D magnesium alloy, needs openings to connect with the steel structure base. Due to the distribution of network intermetallic compounds on the grain boundaries, the casting has low strength and plasticity, and fatigue cracks are prone to appear at the openings, thereby causing the parts to fail. After the casting is fixed on the working platform, the friction stir processing is carried out twice under the conditions of the rotation speed of 300 rpm, the travel speed of 20 mm / min, and the lap rate of 30%. After processing, the grains in this area are refined, The coarse network phase is broken and evenly distributed, and the tensile strength and elongation are increased by 150% and 300% respectively. There is no problem of cracking of the connecting hole during the service of the parts, and the service life is more than doubled.

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Abstract

The invention discloses a method for improving strength of a metal member connection hole. The method is characterized by comprising the steps of: preparing stage: fixing a metal member on a working platform; and stirring friction processing: carrying out stirring friction processing on a region where a hole is opened, on the metal member, wherein special parameters of the friction processing are as follows, to be specific, the rotating speed of a processing tool is 200-4000 turns / min and the advancing speed is 20-1000mm / min. The method has the advantages of short process flow, low cost, easy operation and environment protection, and can solve the connection problem in the industry.

Description

technical field [0001] The invention relates to the field of material processing, and in particular provides a method for improving the strength of connecting holes of metal components. Background technique [0002] When some metal components are working, some parts of them need to be opened (screw holes and light holes) to realize the connection with other components. This area is subjected to repeated tension, compression, torsion, etc. for a long time, and it is very prone to tripping , tearing and other forms of damage, the entire component will fail, and even accidents. If these key working parts are strengthened to improve their performance and improve connection reliability, the life of the entire component can be increased and the occurrence of accidents can be reduced. Plastic deformation processes such as forging, rolling, and extrusion can greatly improve the performance of components, but they will change the shape of parts, and they cannot do anything for compl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/00
Inventor 马宗义倪丁瑞肖伯律王东
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI