High-performance powder metallurgy material and preparation method thereof

A technology of powder metallurgy and powder materials, applied in the field of high-performance powder metallurgy materials and their preparation, can solve the problems of low strength, high price and poor plasticity of sintered steel, and achieve high sintered density, low price, high strength and plasticity Effect

Inactive Publication Date: 2010-05-12
CHANGCHUN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the shortcomings of conventional materials such as low strength, poor plasticity and high price of sintered steel, and provide a high-performance powder metallurgy material, which is an iron-based powder sintered material with high performance

Method used

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  • High-performance powder metallurgy material and preparation method thereof
  • High-performance powder metallurgy material and preparation method thereof
  • High-performance powder metallurgy material and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0035] The mechanical ball milling method is used, that is, the ferrochrome powder is first crushed by high-energy ball milling. With the prolongation of ball milling time, the particle size of the powder becomes smaller and more uniform. However, if the powder is too fine, in view of the well-developed specific surface, it will cause the agglomeration of particles, which will not be well dispersed, and will have an adverse effect on the subsequent pressing and sintering processes. Therefore, it is enough to make the particles reach an appropriate particle size.

[0036] Referring to the figure, it can be seen that the particle size of the original ferrochrome powder is mostly about 30 μm, and most of them are irregular block particles, which will limit the relative sliding of the particles, thereby affecting the loose specific gravity of the powder, and the obtained green compact density is low. figure 2 It shows that after 20h of ball milling, the particles become smaller, t...

Embodiment 2

[0038] Such as Figure 4 Shown is the microstructure and pore morphology after cold pressing and sintering of mixed powder with coarse ferrochrome powder (particle size about 30 μm). Depend on Figure 4 It can be seen that the structure of the coarse powder contains a large number of pores, most of which are polygonal pores with large sizes, and most of the pores are around the undissolved FeCr particles. FeCr powder without ball milling is mostly large polygonal particles, so the addition of coarse powder restricts the flow of powder during compaction, and forms large pores between particles, which affects the densification of the compact.

[0039] refer to Figure 5 It can be seen that in the tissue added with 0.6% fine FeCr powder, the pores are evenly distributed in the tissue in the form of a network, no large polygonal pores are formed, and there are more near-spherical isolated pores, the porosity is obviously reduced, and the density is higher. have a favorable effe...

Embodiment 3

[0042] Figure 8 It is a photo of the cold-pressed sintered metallographic structure with a chromium content of 0.6%. from Figure 8It can be seen that the sintered structure is composed of ferrite and pearlite (sorbite). However, the morphology of pearlite is different from that of general low-alloy forged steel, and no typical lamellar shape is formed, indicating that the diffusion distance of carbon and other alloying elements in γ-Fe is relatively short, and the matrix structure tends to be more granular.

[0043] refer to Figure 9 It can be seen that the results of transmission electron diffraction analysis show that there are ferrite and cementite in the structure. The cementite is short rod-shaped and granular, very small, and the electron diffraction results in this area show intermittent ring-shaped diffraction spots, which is the result of fine polycrystals participating in the diffraction, indicating that the carbide grains are very small.

[0044] Figure 10 ...

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Abstract

The invention discloses a high-performance powder metallurgy material and a preparation method thereof, components of the powder metallurgy material are Fe, Cr, Cu and C; components and contents thereof for preparing the powder metallurgy material are as follows (by weight percent): 0.35 to 0.5 percent of C, 1.3 to 1.5 percent of Cu, 0.6 to 1.0 percent of Cr, 0.6 percent of hard acid zinc 135, and the balance of Fe, wherein the Cr is added in the form of ferrochrome, the adopted ferrochrome is micro-carbon ferrochrome, and the ferrochrome contains 50 percent of chromium, 0.06 percent of carbon, and the balance of Fe; the hard acid zinc 135 is a lubricant; the powder mixing method of the powder metallurgy material is that the ferrochrome is first subjected to high-energy ball milling until particle diameter thereof is within the range of 0.3 to 1 Mum, and then the powder metallurgy material is mixed with other powder evenly; the pressing and sintering method of the powder metallurgy material is that cold pressing is conducted to powder mixed according to a proportion, with the pressure of 600MPa and the pressurizing speed of 150mm / min, and the powder is molded at 600MPa and then kept for 2min; and the sintering is conducted in dissociated ammonia protective atmosphere, with the temperature of 1120 DEG C, and the sintering time of 40min.

Description

technical field [0001] The invention relates to a high-performance powder metallurgy material and a preparation method thereof. Background technique [0002] In recent years, the powder metallurgy industry has developed rapidly. The demand for iron powder, especially alloy iron powder, continues to increase with the development of the automobile industry, and people have higher and higher performance requirements for iron-based sintered structural parts. Therefore, the development of high-density, high-strength, high-plasticity powder metallurgy structural steel and broadening the application field of powder metallurgy steel are the current research and development directions of powder metallurgy. [0003] Iron-based sintered structural steel is a type of product with the largest output and the widest application in the powder metallurgy industry. The performance is equivalent to ordinary cast iron, the tensile strength is only 150-200MPa, and the shape of the manufactured...

Claims

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Application Information

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IPC IPC(8): B22F1/00B22F3/16
Inventor 陈华
Owner CHANGCHUN UNIV OF TECH
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