Breathing type reduction method of metal powder and sintered product thereof

Abstract

The invention relates to a breathing type reduction method of metal powder and a sintered product thereof, comprising the following steps: continuously providing a gaseous reducing agent for metal powder and a sintered product thereof with oxide films in a heating furnace; carrying out a reduction reaction of the oxide films of the metal powder and the sintered product with the gaseous reducing agent at the temperature of 400-900 DEG C so as to obtain the metal powder and the sintered product with the oxygen content of 0.02-0.15%, wherein the reduction reaction is carried out when low air pressure intensity and high pressure intensity are alternately changed, the low air pressure intensity is 10-100Pa, and the high air pressure intensity is 200-30,000Pa. Through the application of the technical scheme, the penetrability of the gaseous reducing agent to the metal powder and the sintered product thereof can be improved, so that the reduction efficiency and effect are improved, the energy consumption is reduced, the quality is improved, and total production cost is reduced.

Description

technical field [0001] The invention relates to a breathing reduction method of metal powder and its sintered products. Background technique [0002] For powder metallurgy sintering and the resulting product quality, sintering activity is an important technological index of metal powder properties. Sintering activity is generally evaluated according to the sintering temperature required for the sintered part to reach a theoretical density of 95% or above. Metal The higher the sintering activity of the powder, the lower the sintering temperature required to obtain the theoretical density. High sintering activity powder is very beneficial to the powder metallurgy sintering process and product quality. Low sintering temperature can reduce mold loss, reduce energy consumption, and improve the mechanical properties of the product, such as the hardness and strength of the sintered product. Especially for metal-bonded diamond sintered products, due to the attenuation of diamond pr...

AI Technical Summary

Problems solved by technology

Although the gas reducing agent has preferential reactivity with the oxygen of the raw metal powder, due to the great difference in density between the gas reducing agent and the metal powder, it is difficult to form all-round contact with the surface of the metal powder, and it is difficult to penetrate into the accumulation Metal powder (or cold pressed blank) inside

Although raising the reduction temperature, increasing the flow rate of the gas reducing agent, prolonging the reduction time or increasing the pressure of the reducing atmosphere, these measures can only solve the problem of metal powder reduction efficiency and effect to a limited extent, and at the same time may cause other process problems, such as high temperature is easy to Agglomeration of metal powder, increase of gas reduction flow rate leads to low utilization rate of reducing gas, prolonging reduction time increases energy consumption and reduces production efficiency, high reducing atmosphere pressure increases equipment cost, etc.

Essentially, the current equipment and process methods do not fully solve the problem of reducing gas penetration into metal powder accumulations (or cold-pressed blanks)