A method for preparing iron-based powder using high energy density plasma rotating electrode

Abstract

The invention discloses a method for preparing iron-based powder by using a high-energy-density plasma rotating electrode. A tungsten electrode is used to emit and transfer a plasma arc, which is mechanically compressed by a compression nozzle and electromagnetically compressed by a focusing coil to form a high-energy-density plasma arc. Heating the end surface of the iron-based alloy rod to make it melt, the iron-based alloy rod rotates at high speed to generate centrifugal force to throw off the molten metal droplets on the end surface, and form a smooth spherical iron-based powder under the action of surface tension. The iron-based powder is composed of the following weight hundred Composition of metal raw materials with different content: C:0.04~0.09wt.%; Cr:16.5~19.5wt.%; Ni:2~6wt.%; B:0.5~3wt.%; Ti:0.3~0.6wt.%; Mo≤2wt.%; Si≤2wt.%; Nb≤3wt.%; V≤2wt.%; O≤0.02wt.%; the balance is Fe and unavoidable impurity elements.

Description

technical field [0001] The invention belongs to the technical field of powder metallurgy, and in particular relates to a method for preparing iron-based powder by using a high-energy-density plasma rotating electrode. Background technique [0002] Iron-based metal materials are widely used in industrial applications due to their low price. According to different performance, they can be divided into stainless steel, wear-resistant steel, mold steel, etc. Stainless steel has good corrosion resistance, but low hardness, poor wear resistance, and limited service life under high-frequency friction and dynamic load conditions. Therefore, the invention of a wear-resistant and corrosion-resistant iron-based material meets market demand. [0003] The wear resistance of the material is often proportional to the hardness. To increase the hardness of the alloy, it is necessary to introduce a hard phase. The dispersion strengthening increases the hardness of the matrix, thereby enhancin...

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Problems solved by technology

However, in the traditional plasma rotating electrode method, the electrode uses a plasma arc to melt a cold electrode rotating at high speed to form a liquefied surface, and the liquefied surface forms a liquid cap under the action of centrifugal force, detaches from the liquid surface, and overcomes the surface tension of the droplet in the processing chamber to form metal powder; traditional plasma The arc is only mechanically compressed by the compression nozzle, and the energy density of the plasma arc is about 10 3 w / cm 2 , although the center temperature of the plasma arc column is high (about 15000-30000 ℃), the dispersion of the plasma arc is large, resulting in the ineffective melting of high melting point phases or refractory metals; the plasma rotating electrode method adjusts the powder particles by adjusting the speed and current diameter, for refractory metals with high melting point or alloys with high melting point phase, it is usually prepared by low speed and high current, but according to the empirical formula, speed, current and particle size are inversely proportional, so the prepared powder particle size is relatively coarse (often greater than 150μm), but high speed and low current cannot melt the hard phase with high melting point, resulting in more slag in the powder (usually the ratio of slag to spherical powder can reach 1:1), while iron-based powder carbonization Borides and borides belong to the high melting point phase, and the above-mentioned problems of coarse powder particle size and excessive slag are prone to occur in the process of plasma rotary electrode powder making

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