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Application of new nitrided steel in manufacturing of diesel engine plunger and barrel assembly

A technology of plunger coupler and nitriding steel, applied in the direction of manufacturing tools, engine components, pistons, etc., can solve problems such as adverse effects on performance, poor pulse-shaped nitrides, and low resistance to high-frequency impact.

Inactive Publication Date: 2021-04-02
CHONGQING HONGJIANG MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

38CrMoAl is a kind of aluminum-containing nitriding steel. After nitriding treatment, it can obtain high surface hardness and good wear resistance, but it is overheating sensitive, the surface of the nitriding layer is more brittle, and the vein nitride is poor. , The ability to resist high-frequency impact is low, and subsequent processing is prone to grinding cracks; large-diameter plungers and plunger sleeves cannot be hardened during quenching and tempering, and free ferrite is easily produced, which will adversely affect the performance of the product
32Cr3Mo1V nitrided steel belongs to a kind of aluminum-free nitriding steel. Compared with 38CrMoAl, the hardenability and brittleness of the nitrided layer after nitriding are significantly improved. However, the hardness after nitriding is low, so that the fatigue resistance, low wear resistance
[0004] The heat treatment properties and mechanical properties after heat treatment of an alloy nitrided steel disclosed in this patent document can be regarded as a suitable choice for the manufacture of diesel engine plunger parts.

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  • Application of new nitrided steel in manufacturing of diesel engine plunger and barrel assembly

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Embodiment Construction

[0018] The application of a kind of new nitrided steel of the present invention in the manufacture of diesel engine plunger coupler is characterized in that the chemical composition of the new nitrided steel selected to manufacture diesel engine plunger coupler is: carbon, 0.33wt%; silicon , 0.63wt%; Manganese, 0.73wt%; Chromium, 3.35wt%; Molybdenum, 0.59wt%; Vanadium, 0.28wt%; impurity, which is an aluminum-free nitrided steel; comprising the following steps:

[0019] The first step is pretreatment before nitriding; the round steel of φ85×305mm is roughly machined to form the blank of the plunger pair, that is, the workpiece, and the workpiece is quenched and tempered to ensure that the core of the workpiece has a better comprehensive mechanical properties;

[0020] Quenching and tempering treatment procedure: first put the workpiece into the air heating furnace, and the interval between the workpieces in the furnace is ≥20mm; then heat up to raise the furnace temperature to...

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Abstract

The invention relates to application of new nitrided steel in manufacturing of a diesel engine plunger and barrel assembly. The application comprises the following steps of 1, pretreatment before nitriding, 2, workpiece cleaning before nitriding, 3, surface nitriding treatment, 4, workpiece grinding, and 5, workpiece vacuum coating. The diesel engine plunger and barrel assembly made of the new nitrided steel has the advantages of aluminum-containing nitrided steel and aluminum-free nitrided steel, the defects of the aluminum-containing nitrided steel and the aluminum-free nitrided steel are overcome, and after composite heat treatment, the use performance of a low-speed diesel engine plunger pump can be improved, and emission is reduced.

Description

technical field [0001] The invention relates to a diesel engine component, in particular to the application of a new nitrided steel in the manufacture of a diesel engine plunger pair. Especially for the heat treatment of plunger couples of marine low-speed diesel engines. Background technique [0002] At present, most of the Wärtsilä, Sulzer and B&W series low-speed machine plunger couples and some medium-speed machine and governor parts are made of 38CrMoAl and 32Cr3Mo1V nitrided steel. 38CrMoAl is a kind of aluminum-containing nitriding steel. After nitriding treatment, it can obtain high surface hardness and good wear resistance, but it is overheating sensitive, the surface of the nitriding layer is more brittle, and the vein nitride is poor. , The ability to resist high-frequency impact is low, and subsequent processing is prone to grinding cracks; large-diameter plungers and plunger sleeves cannot be hardened during quenching and tempering, and free ferrite is easily p...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/22C22C38/24C23C8/02C23C8/26C23C8/80C23C16/34C23C16/50C23C16/52C21D1/25C21D6/00C21D9/00F02F3/00
CPCC21D1/25C21D6/002C21D6/005C21D6/008C21D9/0068C22C38/002C22C38/02C22C38/04C22C38/22C22C38/24C23C8/02C23C8/26C23C8/80C23C16/34C23C16/50C23C16/52F02F3/00
Inventor 杨静陈茂涛王永坤薛建何晓飞
Owner CHONGQING HONGJIANG MACHINERY
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