Method for producing water-atomized prealloyed powder with high cold press formability

Abstract

A method for producing a water-atomized prealloyed powder with high cold press formability, includes the following steps: (a) preparing a −400 mesh semi-finished prealloyed powder; (b) controlling the semi-finished prealloyed powder to have a moisture content of 1 wt % to 2 wt % and an oxygen content of 0.6 wt % to 0.8 wt %, and then drying in a vacuum drying oven at 100° C. for 90 minutes to 120 minutes, so that a preliminary bond is produced between powder particles; and (c) reducing, annealing, crushing, and sieving an initially bonded powder particle. The powder is changed from a spheroidal shape to more complex shapes such as “rice ear shape”, “grape shape”, and “satellite powder”, which greatly improves the cold press formability of the prealloyed powder; the method only performs simple surface modification of the powder without changing other properties, and has wide applicability.

What is claimed is: 
     
         1 . A method for producing a water-atomized prealloyed powder with high cold press formability, comprising the following steps:
 (a) preparing a −400 mesh semi-finished prealloyed powder;   (b) controlling the semi-finished prealloyed powder to have a moisture content of 1 wt % to 2 wt % and an oxygen content of 0.6 wt % to 0.8 wt %, and then drying in a vacuum drying oven at 100° C. for 90 minutes to 120 minutes, so that a preliminary bond is produced between powder particles; and   (c) reducing, annealing, crushing, and sieving an initially bonded powder particle.   
     
     
         2 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 1 , wherein in step (a), the semi-finished prealloyed powder adopts a water atomization pulverizing process, and the specific operation thereof is: using high-pressure water to crush a metallic solution into a micro droplet in an atomizer, and filtering after cooling, wherein, the temperature of the metallic solution is 1450 to 1750° C., the diameter of a nozzle is 4 to 5 mm, a water flow intersection angle is 40°, a water pressure is 65 Mpa to 80 Mpa, and a water flow rate is 180 L/min to 200 L/min. 
     
     
         3 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 2 , wherein in step (a), the metallic solution is any one or a combination of two or more of iron, copper, nickel, tin, zinc, cobalt, tungsten, molybdenum, vanadium, and chromium. 
     
     
         4 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 2 , wherein in step (a), the semi-finished prealloyed powder is one of iron copper, iron copper nickel, iron copper nickel tin, iron copper cobalt tin, and iron tungsten molybdenum vanadium chromium. 
     
     
         5 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 1 , wherein in step (c), the reduction temperature is 500 to 600° C., and the reduction time is 8 to 10 hours. 
     
     
         6 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 1 , wherein in step (c), the annealing operation is: annealing at a temperature of 800 to 1050° C. and a vacuum degree of 10 −1  Kpa for 5 to 6 hours. 
     
     
         7 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 1 , wherein in step (c), a continuous impact crusher is used to crush, and the crusher has a speed of 2000 to 3000 rpm. 
     
     
         8 . The method for producing a water-atomized prealloyed powder with high cold press formability according to  claim 1 , wherein in step (c), a 100 to 300 mesh screen is used to sieve.