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Technique for strengthening local surface of engine piston

A technology of surface strengthening and process method, applied in the direction of engine components, machines/engines, pistons, etc., can solve the problems of difficult to change thermal expansion performance, large thermal expansion coefficient, small thermal expansion coefficient, etc., to improve hardness and wear resistance, good Service performance, the effect of reducing the thermal expansion coefficient

Inactive Publication Date: 2012-10-10
SHANGHAI JIAO TONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the prepared cast heat-resistant rare-earth magnesium alloy engine piston has good high-temperature strength and creep resistance, these patents are to improve the heat resistance and wear resistance of the piston base alloy by optimizing the alloy composition to meet the working requirements of the piston , and it is very limited to improve the wear resistance of the piston only by adjusting the composition of the alloy material; in addition, the thermal expansion coefficient of the magnesium alloy is relatively large, and it is difficult to change its thermal expansion performance through the adjustment of the alloy composition, while the piston skirt and The friction between the cylinder liners is one of the main factors affecting the life of the automobile engine. Therefore, for the piston skirt, the demand for small thermal expansion coefficient and good wear resistance is more urgent

Method used

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  • Technique for strengthening local surface of engine piston
  • Technique for strengthening local surface of engine piston
  • Technique for strengthening local surface of engine piston

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Example 1 (see figure 1 ):

[0033] (1) The alloy material of the magnesium alloy engine piston 3 is Mg-15Gd-2.5Zn-0.6Zr (wt.%), and the surface of the piston 3 is cleaned and pretreated after the piston 3 is solid solution treated.

[0034] (2) A concave groove 1 with a width of 30 mm and a depth of 1.0 mm is formed on the surface of the skirt of the engine piston 3 in the circumferential direction with a lathe.

[0035] (3) On the skirt of the engine piston 3 and the concave groove 1, the high-hard wear-resistant layer 2 is sprayed by plasma spraying, and a ceramic coating with a thickness of 0.2mm is formed on the surface of the piston 3. The spraying material is 50μm in diameter. Al 2 O 3 -TiO 2 50% mixed particles.

[0036] (4) Clamp the engine piston 3 on the rotating shaft of the friction stir welding machine with adjustable speed, and align the stirring head of the friction stir welding machine with the starting point of the concave groove 1 of the piston 3 to be proces...

Embodiment 2

[0040] Example 2 (see figure 2 ):

[0041] (1) The alloy material composition of the magnesium alloy engine piston 3 is Mg-10Gd-3Y-2Zn-0.4Zr (wt.%). The casted piston 3 is solid-dissolved at 525°C for 15 hours, and after air cooling, the piston 3 The surface is cleaned and pretreated.

[0042] (2) Use a lathe to make a concave groove 1 with a width of 20 mm and a depth of 0.2 mm on the skirt of the engine piston 3 in the circumferential direction;

[0043] (3) At the skirt of the engine piston 3 and the concave groove 1, the high-hard wear-resistant layer 2 is sprayed by flame spraying, and a ceramic coating with a thickness of 0.1mm is formed on the surface of the piston 3. The spraying material is 100μm in diameter. SiC particles.

[0044] (4) Clamp the engine piston 3 on the rotating shaft of the friction stir welding machine with adjustable speed, and align the stirring head of the friction stir welding machine with the starting point of the concave groove 1 of the piston 3 to b...

Embodiment 3

[0048] (1) The alloy material composition of the aluminum alloy engine piston is Al-13Si-3Cu-2Ni-1.0Mg (wt.%), and the surface of the piston is cleaned and pretreated after the casting of the piston is solid solution treated.

[0049] (2) Use a lathe to cut a concave groove with a width of 2mm and a depth of 0.25mm in the circumferential direction of the skirt of the engine piston;

[0050] (3) At the piston skirt and concave groove of the engine, the high-hard wear-resistant layer is sprayed by thermochemical reaction thermal spraying to form a ceramic coating with a thickness of 0.28mm on the piston surface. The spraying material is commercial Al 2 O 3 , TiO 2 , SiO 2 A mixed powder of five substances, ZnO and Al, the particle size of the mixed powder is 200nm.

[0051] (4) Clamp the engine piston on the rotating shaft of the friction stir welding machine with adjustable speed to align the stirring head with the starting point of the concave groove of the piston to be processed; the...

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Abstract

The invention relates to a technique for strengthening local surface of an engine piston. A high-hardness abrasion resistant layer is formed on a piston skirt section surface slotted in advance by adopting a thermal spraying method, stirring and rubbing processing is carried out on the high-hardness abrasion resistant layer and surface of a base body, and a particle reinforced phase compound layer is formed under the action of thermal mechanical stirring, thus hardness and abrasion resistance of the surface of the piston are improved, the piston has the characteristics that the interior is tough and the exterior is hard, and coefficient of thermal expansion is reduced. The technique disclosed by the invention has the advantages of simplicity in operation, high efficiency, low cost and obvious effect and can be used for local surface strengthening of the engine piston made from aluminium alloy or magnesium alloy.

Description

Technical field [0001] The invention belongs to the technical field of automobile manufacturing, and specifically relates to a process method for strengthening the partial surface of an engine piston. Background technique [0002] The engine is the heart of the car, and the piston is the most critical part of the engine. Pistons work under the conditions of high temperature, high pressure, high speed, corrosion, and friction. In addition to requiring the material to have sufficient rigidity and strength, the piston also needs to have a small coefficient of thermal expansion, so that the piston and the cylinder maintain a proper gap during operation. In order to reduce noise; in addition, with the advancement of the lightweight process of automobiles, the use of lightweight pistons can not only reduce weight, reduce fuel consumption, and reduce emissions, but also because the piston is a high-speed reciprocating part, its lightweight is beneficial to improve the engine’s The outp...

Claims

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Application Information

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IPC IPC(8): B23P15/10C23C4/02C23C4/10C23C4/18F02F3/10C23C4/06C23C4/08C23C4/11C23C4/129C23C4/134
Inventor 彭立明郑飞燕吴玉娟付彭怀王渠东丁怀新
Owner SHANGHAI JIAO TONG UNIV
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