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A preparation method of iron-based alloy and its application in testing the starting temperature of martensitic transformation

A technology for iron-based alloys and alloy powders, which is applied in the field of preparation of iron-based alloys, can solve the problems of difficulty in temperature, insufficient sensitivity, and immature preparation technology of micron-level single crystal alloy powders, and achieves the increase of martensite nucleation sites. Effect

Inactive Publication Date: 2018-04-17
HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

(2) The preparation technology of micron-sized single crystal alloy powder is not mature enough
Small-scale single-crystal grains have no grain boundaries and few line defects such as dislocations. Due to the limitation of preparation technology, the research on martensitic transformation is correspondingly lacking.
(3) The sensitivity of the instrument for measuring magnetic parameters is not enough
If the sensitivity of the instrument for measuring magnetic parameters such as magnetic susceptibility is not enough, the accurate determination of M S temperature is difficult

Method used

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  • A preparation method of iron-based alloy and its application in testing the starting temperature of martensitic transformation
  • A preparation method of iron-based alloy and its application in testing the starting temperature of martensitic transformation
  • A preparation method of iron-based alloy and its application in testing the starting temperature of martensitic transformation

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Experimental program
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Effect test

Embodiment 1

[0031] This embodiment includes the following steps:

[0032] (1) Preparation and classification of alloy powder: using high-purity iron, high-purity nickel and high-purity cobalt as raw materials, the mass fraction of iron in the high-purity iron is greater than or equal to 99.9%, and the high-purity nickel is electrolytic nickel with a mass fraction of nickel greater than or equal to 99.96%, The high-purity cobalt is electrolytic cobalt with a mass fraction of cobalt greater than or equal to 99.98%, which is smelted in a vacuum induction furnace to obtain 67.9Fe-31.6Ni- 0.5Co master alloy, and then overheated to 2020 K, start gas atomization powder, the atomization medium used is nitrogen, atomization pressure is 6.0 MPa, the powder body obtained by gas atomization powder is sieved under 500 mesh, Select the powder with a particle size of less than 500 mesh after sieving, that is, the powder with a particle size of ≤25 μm, and then classify it through an air classifier. Pow...

Embodiment 2

[0036] This embodiment includes the following steps:

[0037] (1) Preparation and classification of alloy powder: using high-purity iron, high-purity nickel and high-purity cobalt as raw materials, the mass fraction of iron in the high-purity iron is greater than or equal to 99.9%, and the high-purity nickel is electrolytic nickel with a mass fraction of nickel greater than or equal to 99.96%, The high-purity cobalt is electrolytic cobalt with a mass fraction of cobalt greater than or equal to 99.98%, which is smelted in a vacuum induction furnace to obtain 67.9Fe-31.6Ni- 0.5Co master alloy, and then overheated to 2020 K, start gas atomization powder, the atomization medium used is nitrogen, atomization pressure is 6.0 MPa, the powder body obtained by gas atomization powder is sieved under 500 mesh, Select the powder with a particle size of less than 500 mesh after sieving, that is, the powder with a particle size of ≤25 μm, and then classify it through an air classifier. Pow...

Embodiment 3

[0042] This embodiment includes the following steps:

[0043] (1) Preparation and classification of alloy powder: using high-purity iron, high-purity nickel and high-purity cobalt as raw materials, the mass fraction of iron in the high-purity iron is greater than or equal to 99.9%, and the high-purity nickel is electrolytic nickel with a mass fraction of nickel greater than or equal to 99.96%, The high-purity cobalt is electrolytic cobalt with a mass fraction of cobalt greater than or equal to 99.98%, which is smelted in a vacuum induction furnace to obtain 67.9Fe-31.6Ni- 0.5Co master alloy, and then overheated to 2020 K, start gas atomization powder, the atomization medium used is nitrogen, atomization pressure is 6.0 MPa, the powder body obtained by gas atomization powder is sieved under 500 mesh, Select the powder with a particle size of less than 500 mesh after sieving, that is, the powder with a particle size of ≤25 μm, and then classify it through an air classifier. Pow...

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Abstract

The invention relates to a preparation method of an iron base alloy. The preparation method comprises the following steps: (1) high-purity iron, high-purity nickel and high-purity cobalt are used as raw materials for smelting in a vacuum induction electric furnace to obtain a 67.9Fe-31.6Ni-0.5Co mother alloy; then, after the mother alloy is overheated to reach 1980-2020 K, the gas atomization powder milling is started; and the powder is screened under 500 meshes, and is classified by an airflow classifier; (2) the powder with the smallest particle size after classification by the airflow classifier in the step (1) is put under a scanning electron microscope for observation to obtain powder with smooth particle surfaces and no grain boundary to serve as original single-crystal alloy powder; and (3) the original single-crystal alloy powder obtained in the step (2) is put in a vacuum sintering furnace for loose sintering by 0-60 min to obtain alloy powder. The prepared alloy powder is applied to test of a martensite phase transformation start temperature; and the corresponding MS temperature large increasing rules along with large increment of sintering necks on prepared iron-base alloy powder particles in a certain range are discovered.

Description

technical field [0001] The invention relates to a preparation method of an iron-based alloy and its application in testing the starting temperature of martensitic transformation. Background technique [0002] The application of martensitic phase transformation laws such as strengthening mechanism, shape memory effect and superelasticity in modern industry has exerted remarkable effects. The research on martensitic transformation has gradually penetrated from the appearance to the essence of the transformation, but some fundamental issues are still incompletely understood. Martensitic transformation start temperature M S It has always been a concern of many scientific workers and people engaged in production practice. Calculation of M using thermodynamic treatment S The work on temperature and verifying the phase transition process is still in its infancy. m S From high temperature to low temperature, the form of martensite will change, and the kinetic process of phase t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C33/02G01N25/12
CPCC22C33/0285G01N25/12
Inventor 孙世清
Owner HEBEI UNIVERSITY OF SCIENCE AND TECHNOLOGY