Mixing method of iron-based powder metallurgy bonding powder

Abstract

The invention relates to a mixing method of iron-based powder metallurgy bonding powder. The mixing method comprises: (1) pre-mixing: according to a formulation of powder metallurgy, feeding powder materials into a powder mixing machine, vacuuming the inner cavity of the powder mixing machine after feeding, wherein the inner pressure of the powder mixing machine is at least less than 30000 Pa, and then mixing for 10-60 minutes under a negative pressure state; (2) heating for dissolving: based on the pre-mixed powder material serving as a base powder, adding 2wt% of copper powder, 0.8wt% of graphite powder and 0.8wt% of a lubricant, while standing and heating, gradually rising the heating temperature to 10 DEG C above the melting point of the lubricant so as to reach a predetermined temperature, and then insulating; and (3) cooling and re-mixing: when the temperature of the power is lower than 50 DEG C, controlling the time of re-mixing to be within 2-30 minutes. The mixing method has the beneficial effects that the visual dusting conditions of the mixed powder subjected to bonding treatment are obviously reduced, which indicates that the bonding effect of the graphite and lubricant is good; and simultaneously, the apparent density, mobility and compressibility of the mixed powder are well maintained.

Description

technical field [0001] The invention belongs to the technical field of preparation of special new materials, in particular to a method for mixing iron-based powder metallurgy bonding powder. Background technique [0002] Iron-based powder metallurgy parts have been widely used due to their advantages of large quantities, high precision and low cost. Its application has penetrated into the manufacturing field of key auto parts. [0003] Iron-based powder metallurgy usually adds copper powder, nickel powder, graphite powder, lubricants and other additives to the iron base powder as its alloy strengthening elements or functional elements. There are differences in particle shape. How to mix them uniformly and maintain a uniform state is the key to the mixed powder, and it is also the main bottleneck restricting the further improvement of the dimensional accuracy and mechanical performance stability of iron-based powder metallurgy parts. [0004] In order to solve the above pro...

AI Technical Summary

Problems solved by technology

These methods are nothing more than two forms: one is to introduce a liquid binder to bond low specific gravity additives, such as graphite and lubricants, but the bonding effect for high specific gravity additives such as copper powder or nickel powder is limited. In addition, this method It will also cause the disadvantage of unstable fluidity of the mixed powder

The other is to use a solvent to dissolve the solid binder, sprinkle the solution on the mixed powder, and then heat to volatilize the solvent. The binder in this method is evenly distributed and the bonding effect is good, but the solvent Recycling is often difficult, and improper handling will cause environmental pollution; incomplete volatilization will easily cause residues in the powder, which will pose a hazard to the health of subsequent operators