Powder metallurgy stainless steel and preparation method thereof

A technology of powder metallurgy and stainless steel, applied in the field of powder metallurgy stainless steel and its preparation, can solve the problems of reduced density, low mechanical properties and low corrosion resistance

Active Publication Date: 2016-10-26
SHANDONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, due to a certain amount of residual pores inside the powder metallurgy stainless steel, which will lead to a decrease in its density, compared with cast and forged stainless steel, the mechanical properties and corrosion resistance of powder metallurgy stainless steel are lower

Method used

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  • Powder metallurgy stainless steel and preparation method thereof
  • Powder metallurgy stainless steel and preparation method thereof
  • Powder metallurgy stainless steel and preparation method thereof

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preparation example Construction

[0030] The invention provides a method for preparing powder metallurgy stainless steel, which uses components including the following mass content as raw materials: 95-98 wt% stainless steel powder, 1.5-2.5 wt% Cu powder and 0.5-2.5 wt% Sn powder;

[0031] Specifically include the following steps:

[0032] (1) stainless steel powder, Cu powder, Sn powder and lubricant are mixed, obtain mixed powder;

[0033] (2) Compressing the mixed powder obtained in the step (1) to obtain a green body;

[0034] (3) Pre-sintering the green body obtained in the step (2) to obtain a pre-sintered body;

[0035] (4) Sintering the pre-sintered green body obtained in the step (3) to obtain powder metallurgy stainless steel.

[0036] In the embodiment of the present invention, the preparation process of powder metallurgy stainless steel is preferably as follows figure 1 As shown, 316LN stainless steel powder, copper powder, tin powder and zinc stearate are mixed and ball milled to obtain a mix...

Embodiment 1

[0080] Using 97wt% of 400-mesh stainless steel powder, 2wt% of 400-mesh copper powder, and 1wt% of 400-mesh tin powder as raw materials, the metal powder was mixed, and 0.6% zinc stearate was added to the metal powder mass, and dried by a planetary high-energy ball mill. The grinding mixture, the tank body and the grinding balls are all made of stainless steel, the ball-to-material ratio is 2:1, the rotating speed is 180r / min, and the ball milling time is 1h.

[0081] The uniformly mixed powder was pressed into shape at 700MPa. The sintered sample used for the electrochemical test was a disc with a diameter of 23mm and a thickness of 5mm; the tensile sample used for the mechanical property test was 140mm×10mm×5mm.

[0082] Under the condition of vacuum degree of 0.1Pa, the pressed samples were heated up to 350°C at a rate of 4°C / min, kept at a temperature of 30min, then raised to 750°C at a rate of 5°C / min, kept at a temperature of 60min for pre-sintering, and then Raise the t...

Embodiment 2

[0085] Using 96wt% of 400-mesh stainless steel powder, 2wt% of 400-mesh copper powder, and 2wt% of 400-mesh tin powder as raw materials, the metal powder is mixed, and 0.6% zinc stearate is added to the metal powder, and it is dried by a planetary high-energy ball mill. The grinding mixture, the tank body and the grinding balls are all made of stainless steel, the ball-to-material ratio is 2:1, the rotating speed is 180r / min, and the ball milling time is 1h.

[0086]The uniformly mixed powder was pressed into shape at 700MPa. The sintered sample used for the electrochemical test was a disc with a diameter of 23mm and a thickness of 5mm; the tensile sample used for the mechanical property test was 140×10×5mm.

[0087] Under the condition of vacuum degree of 0.1Pa, the pressed sample was heated to 350°C at a rate of 5°C / min, kept for 30min, and then heated to 750°C at a rate of 5°C / min for pre-sintering for 60min, and then pre-sintered at a rate of 6.5 The rate of °C / min is rais...

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Abstract

The invention provides powder metallurgy stainless steel and a preparation method thereof. The powder metallurgy stainless steel is prepared from, by weight, 95-98% of stainless steel powder, 1.5-2.5% of Cu powder and 0.5-2.5% of Sn powder. The stainless steel powder, the Cu powder, the Sn powder and a lubricating agent are mixed, pressed, pre-sintered and sintered, and then the powder metallurgy stainless steel is obtained. The porosity of the powder metallurgy stainless steel provided by the invention is lower than 5%; and compared with traditional powder metallurgy 316LN stainless steel, the tensile strength is improved by 21%, the elongation percentage is increased by 56%, the hardness is improved by 27%, and the pitting potential is improved by 60% after the powder metallurgy stainless steel is soaked in a 3.5wt% NaCl solution for 15 days. The preparation method provided by the invention is easy and convenient to operate and suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of metal materials, in particular to a powder metallurgy stainless steel and a preparation method thereof. Background technique [0002] The reason why stainless steel can resist corrosion is that a protective passivation film can be formed on its surface, which can prevent O 2 Penetrate further into the alloy. In the inland environment, even if the passivation film is damaged, it can be quickly re-formed in the air, so the corrosion resistance is better. However, once this layer of passivation film is destroyed and lacks the conditions or ability of self-passivation, stainless steel will corrode. Especially in the marine environment, although Cl - It cannot penetrate this oxide film itself, but due to water vapor and Cl - It is preferentially adsorbed on the defect of the passivation film on the surface of stainless steel, so that the ion conductance and dissolution rate of the passivation film there ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/02C22C38/20C22C38/42
CPCC22C33/006C22C33/02C22C38/008C22C38/20C22C38/42
Inventor 宫建红刘盛男
Owner SHANDONG UNIV
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