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CN-116900303-B - Balance weight and preparation method thereof

CN116900303BCN 116900303 BCN116900303 BCN 116900303BCN-116900303-B

Abstract

The invention belongs to the technical field of balance weights, and discloses a balance weight and a preparation method thereof. The balance weight is prepared from the alloy powder raw materials for the balance weight, wherein the sintering property of the alloy material can be obviously improved by adding the nano ferroferric oxide sintering aid into the alloy powder for the balance weight, and the density and the tensile strength of the balance weight can be improved.

Inventors

  • Shu Ruizhe
  • Shu Kezhang
  • XIONG WEI

Assignees

  • 江门佳久精密制造科技有限公司

Dates

Publication Date
20260508
Application Date
20230706

Claims (7)

  1. 1. The preparation method of the balance weight is characterized by comprising the following steps: (1) Pressing the alloy powder for the balance weight which is uniformly mixed to obtain a green body, wherein the alloy powder for the balance weight comprises prealloy powder, copper powder, a sintering aid and a lubricant; The prealloy powder comprises the following components, by mass, 0.5-2% of C, 0-2% of Ni, 10-25% of Mn, 0.1-1% of Si, 0-0.9% of P, and the balance of Fe and unavoidable impurities; the sintering aid is nano ferroferric oxide and/or silane coupling agent modified nano ferroferric oxide, wherein the average particle size of the nano ferroferric oxide is 10-1000nm; the weight percentage of the nano ferroferric oxide in the alloy powder for the balance weight is 0.2-1%, the weight percentage of the copper powder in the alloy powder for the balance weight is 2-11%, and the silane coupling agent accounts for 0.2-1% of the weight of the nano ferroferric oxide; Dispersing nano ferroferric oxide in ethanol, adding a silane coupling agent under stirring to carry out modification reaction, carrying out solid-liquid separation after the reaction, and drying the solid to obtain the nano ferroferric oxide modified by the silane coupling agent; (2) And (3) presintering the green embryo in a reducing atmosphere, sintering, and cooling to obtain the balance weight, wherein the presintering temperature is 500-700 ℃ and the presintering time is 0.5-1.5h.
  2. 2. The method of manufacturing a balance weight of claim 1, comprising at least one of the following a-C: A. the average grain diameter of the nano ferroferric oxide is 50-500nm; B. the mass percentage of the nano ferroferric oxide in the alloy powder for the balance weight is 0.4-0.8%; C. the mass percentage of the copper powder in the alloy powder for the balance weight is 5-10%.
  3. 3. The method for producing a weight according to claim 1, wherein the lubricant is at least one of hydrocarbons, fatty acids, fatty acid amides, esters, alcohols and metal soaps, and the weight percentage of the lubricant in the alloy powder for a weight is 0.1 to 1%.
  4. 4. The method for preparing a balance block according to claim 1, wherein the temperature of the modification reaction is 50-80 ℃, and the time of the modification reaction is 1-12 hours.
  5. 5. The method for preparing a balance weight according to claim 1, wherein the silane coupling agent comprises at least one of gamma-aminopropyl triethoxysilane, gamma-glycidoxypropyl trimethoxysilane, gamma-methacryloxypropyl trimethoxysilane.
  6. 6. The method for producing a weight according to claim 1, wherein the sintering treatment is performed at a temperature of 1100 to 1250 ℃ for a time of 0.5 to 1 hour, the mixing and the pressing are performed in an inert gas atmosphere, the pressing is performed at a pressure of 600 to 1200MPa, and the reducing atmosphere includes at least one of a hydrogen atmosphere and an ammonia decomposing atmosphere.
  7. 7. A balance weight produced by the method for producing a balance weight according to any one of claims 1 to 6.

Description

Balance weight and preparation method thereof Technical Field The invention belongs to the field of balance weights, and particularly relates to a balance weight and a preparation method thereof. Background In order to meet the requirements of high-performance rotors, compressor weights are generally required to have non-magnetic or low-magnetic properties, high density, accurate quality and good mechanical properties. Currently, the process for preparing the balance weight mainly comprises powder metallurgy and casting. Compared with the traditional casting process, the powder metallurgy process has the advantages of high efficiency, high material utilization rate, simple manufacturing process, environmental friendliness and the like, and therefore, the powder metallurgy process has been widely applied to various parts of compressors. In order to meet the performance requirements of the balance weight, the density of the balance weight prepared by powder metallurgy is critical, and the mechanical property, the quality and the volume of the balance weight with too low density are difficult to meet. At present, the sintering density and the compactibility are generally improved by adding a certain amount of copper, but the increasing of the addition amount of copper is necessary to increase the production cost, the melting point of copper is lower than the conventional sintering temperature, partial liquid phase exists in the sintering process, and the shape and the size of the prepared balance weight are difficult to control, so that the use amount of copper is reduced as much as possible. Therefore, there is still a need to develop a new alloy powder process for preparing weights in order to solve the current drawbacks of powder metallurgy for preparing weights. Disclosure of Invention Aiming at the defects of lower density and poor mechanical property of the powder metallurgy preparation balance block related to the prior art, the invention provides the high-density balance block prepared by preparing the alloy powder for the balance block in advance so as to improve the sintering property of the alloy. In order to achieve the above purpose, the method specifically comprises the following technical scheme: an alloy powder for a balance weight comprises prealloy powder, copper powder, a sintering aid and a lubricant; The prealloy powder comprises the following components, by mass, 0.5-2% of C, 0-2% of Ni, 10-25% of Mn, 0.1-1% of Si, 0-0.9% of P, and the balance of Fe and unavoidable impurities; the sintering aid is nano ferroferric oxide and/or silane coupling agent modified nano ferroferric oxide, wherein the average particle size of the nano ferroferric oxide is 10-1000nm; The weight percentage of the nano ferroferric oxide in the alloy powder for the balance weight is 0.2-1%, and the weight percentage of the copper powder in the alloy powder for the balance weight is 2-11%. The nano ferroferric oxide has the characteristics of nano materials, particularly has high surface energy, high activity, good dispersibility and fluidity, can be used as an auxiliary agent for activating sintering effect in the sintering process of the alloy powder for the balance weight, improves the sintering performance of the alloy powder, reduces the porosity in the alloy, and promotes and improves the pore distribution and the densification condition of the alloy, thereby realizing high densification and high tensile strength of the balance weight. This is because nano ferroferric oxide is reduced to new tiny high-activity Fe in a reducing atmosphere in a sintering process, the new tiny high-activity Fe has a certain activation sintering effect, meanwhile, valence-variable Fe 3+ and valence-variable Fe 2+ exist in the ferroferric oxide, the self reduction-oxidation reversible process also has a certain sintering assisting effect, the activity of the new tiny high-activity Fe is higher than that of ferric oxide, and in addition, a trace amount of H 2 O is generated in the reduction-oxidation reversible process, but the sintering process is easy to reduce in the reducing atmosphere, the atomic activity is increased, and the activation sintering effect is also realized to a certain extent. In addition, the ferroferric oxide has magnetism, but the added quantity is small, and the ferroferric oxide can be converted into paramagnetic at the subsequent sintering temperature higher than the Curie temperature, so that the magnetism becomes weaker relatively, and the influence on the overall magnetism of the balance block is small, so that the finally prepared balance block is still kept within 0.15mT, and the requirement of non-magnetism or extremely low magnetism of the balance block is completely met. The nano ferroferric oxide has certain relation between the activity and the particle size, the particle size is larger than 1000nm, the activity is relatively low, the active sintering effect is not large, the particle size is too sma