Preparation method of high-nitrogen stainless steel spherical powder

A high-nitrogen stainless steel and spherical powder technology, applied in the field of high-nitrogen stainless steel spherical powder preparation, can solve the problems of poor batch stability of powder, high price of high-purity element powder, low powder fluidity, etc. The effect of improving the yield of fine powder and suppressing the precipitation of nitrogen

Inactive Publication Date: 2016-06-01
SINO EURO MATERIALS TECH OF XIAN CO LTD
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Problems solved by technology

The high-pressure smelting-gas atomization method is smelting in a high-pressure nitrogen atmosphere to increase nitrogen in the stainless steel melt, and then use a high-pressure nitrogen gas flow to blow and atomize the molten liquid to make powder. This method has strict requirements on high-pressure smelting equipment, and the actual production There are potential safety hazards in the process, and the powder batch stability is poor, it is easy to generate satellite powder and hollow powder, which is not conducive to the performance of powder formed parts
Combining mechanical alloying and solid-state nitriding, firstly mix various single element powders and fully ball mill to obtain fine powder particles, then nitriding the solid powders in the austenite phase region temperature by flowing nitrogen, and finally adding pure iron Configured to the nominal composition of the alloy, and continue ball milling to obtain a nearly spherical coated powder. This method has a complicated process, high price of high-purity element powder, and huge cost of ball milling time, which is not suitable for industrial scale production.
In addition, gas atomization and mechanical alloying powders have low sphericity and low powder fluidity, which make it difficult to meet the requirements of powder metallurgy forming process for raw materials
[0005] Therefore, in order to solve the difficulties such as low sphericity, poor fluidity, high cost, and poor batch stability of high-nitrogen stainless steel powder, eliminate potential safety hazards of high-pressure smelting vessels, and avoid other problems that occur in the preparation of high-nitrogen stainless steel powder, the present invention proposes A kind of preparation method of high nitrogen stainless steel spherical powder

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Embodiment 1

[0026] Embodiment 1: Preparation of high nitrogen austenitic stainless steel spherical powder

[0027] The percentage by weight is: Cr17.5%, Mo2.6%, Ni13.5%, the rest is Fe element, and the austenitic stainless steel melting and casting raw material with a total weight of 100kg is used for smelting and obtaining ingots; secondly, through the forging process, the stainless steel The ingot is made into a forged bar with a microstructure density of 99.6%. After machining on a lathe and a precision CNC lathe, an austenitic stainless steel electrode rod with a diameter of 40mm and a length of 800mm is obtained, and the surface roughness is 1.6μm; The obtained electrode rod is placed in the electrode rod installation chamber 2, and the nitrogen atomization chamber 1 is evacuated until the vacuum degree of the equipment reaches 1×10 -3 Fill high-purity nitrogen at Pa, and the partial pressure of nitrogen in the equipment is 1.5×10 5 Pa; turn on the atomization equipment to prepare...

Embodiment 2

[0029] Example 2: Preparation of high-nitrogen nickel-free austenitic stainless steel spherical powder

[0030] The percentage by weight is: Cr18.5%, Mn13%, Mo3.5%, the rest is Fe element, and the austenitic stainless steel melting and casting raw material with a total weight of 100kg is used to melt and obtain ingots; secondly, through forging process, the stainless steel ingots are cast A forged bar with a microstructure density of 99.8% was made, and after machining on a lathe and a precision CNC lathe, an austenitic stainless steel electrode rod with a diameter of 60 mm and a length of 600 mm was obtained, with a surface roughness of 3.2 μm; the obtained electrode The rod is placed in the stainless steel electrode rod installation chamber 2, and the nitrogen atomization equipment 1 is vacuumed until the vacuum degree of the atomization equipment reaches 5×10 -3 Fill high-purity nitrogen at Pa, and the partial pressure of nitrogen in the atomization equipment is 2.5×10 5...

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Abstract

The invention provides a preparation method of high-nitrogen stainless steel spherical powder. The preparation method comprises the following steps: preparing materials according to stainless steel components and carrying out a melting process of a mother alloy ingot; preparing the mother alloy ingot into a common stainless steel electrode bar through forging and machining; carrying out pre-vacuumizing treatment on atomization equipment and introducing high-purity nitrogen gas; conveying the electrode bar into an atomization chamber through a feeding system and heating the end face of the electrode bar by using a plasma torch; ionizing the nitrogen gas in an electric arc region into nitrogen ions, high-energy nitrogen molecules and un-ionized nitrogen neutral atoms so as to improve the nitrogen content of stainless steel; preparing metal liquid drops by using a centrifugal effect of a rotary electrode and instantly condensing the metal liquid drops into spherical metal powder; after cooling the high-nitrogen stainless steel spherical powder, removing non-metal impurities through an electrostatic impurity removing device; and finally, carrying out powder package by adopting multilayered vacuum heat sealing. The preparation method of the high-nitrogen stainless steel spherical powder has the characteristics of high production efficiency, strong batch stability, high fine powder yield and the like; and the stainless steel spherical powder with high nitrogen content, good purity, strong mobility and smooth and clean surface can be easily prepared.

Description

technical field [0001] The invention belongs to the technical field of metal and alloy powder preparation, and in particular relates to a preparation method of high-nitrogen stainless steel spherical powder. Background technique [0002] At the beginning of the 20th century, in order to improve the strength of steel materials, researchers tried to add nitrogen to steel. Nitrogen, as a strong austenite stabilizing element and interstitial atom element, can not only expand the austenite phase region, but also improve the strength and creep of steel. Variable resistance and corrosion resistance; and nitrogen is also a stable, cheap, and unlimited resource element, which can significantly reduce the cost by replacing expensive nickel in some grades of steel. [0003] Speidel defines "high nitrogen steel" as a special steel whose actual nitrogen content in stainless steel exceeds the limit value it can reach under normal pressure conditions (ie 0.1MPa). Nitrogen content of super...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/10C22C38/44C22C38/38C22C38/22
CPCB22F9/10B22F2999/00C22C38/001C22C38/22C22C38/38C22C38/44
Inventor 赵霄昊左振博王庆相陈小林韩志宇徐伟张鹏梁书锦张平祥
Owner SINO EURO MATERIALS TECH OF XIAN CO LTD
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