Brass alloy powder, brass alloy extruded material, and method for producing the brass alloy extruded material

Abstract

Brass alloy powder has a brass composition formed by a mixed phase of α-phase and β-phase, and contains 0.5 to 5.0 mass % of chromium. The chromium includes a component that is solid-solved in a mother phase of brass, and a component that is precipitated at crystal grain boundaries.

1 . Brass alloy powder having a brass composition formed by a mixed phase of α-phase and β-phase, and containing 0.5 to 5.0 mass % of chromium, wherein
 said chromium includes a component that is solid-solved in a mother phase of brass, and a component that is precipitated at crystal grain boundaries. 
 
     
     
         2 . The brass alloy powder according to  claim 1 , wherein
 said component that is solid-solved in said mother phase of said brass includes a component that is solid-solved and dispersed in said mother phase, and a component that is dispersed in said mother phase as precipitates.   
     
     
         3 . The brass alloy powder according to  claim 1 , wherein
 a content of said chromium is 1.0 to 2.4 mass %.   
     
     
         4 . The brass alloy powder according to  claim 1 , wherein
 said powder contains at least one element selected from the group consisting of nickel, manganese, zirconium, vanadium, titanium, silicon, aluminum, and tin.   
     
     
         5 . The brass alloy powder according to  claim 1 , wherein
 said powder is rapidly solidified powder.   
     
     
         6 . The brass alloy powder according to  claim 5 , wherein
 said rapidly solidified powder is powder rapidly solidified by a water atomizing method.   
     
     
         7 . A brass alloy extruded material, which is produced by extruding an aggregate of brass alloy powder having a brass composition formed by a mixed phase of α-phase and β-phase, and containing 0.5 to 5.0 mass % of chromium, wherein
 said chromium includes a component that is solid-solved in a mother phase of brass, and a component that is precipitated at crystal grain boundaries. 
 
     
     
         8 . The brass alloy extruded material according to  claim 7 , wherein
 said brass alloy extruded material has a 0.2% proof stress of 300 MPa or more.   
     
     
         9 . The brass alloy extruded material according to  claim 7 , wherein
 said brass alloy extruded material has a tensile strength of 500 MPa or more.   
     
     
         10 . The brass alloy extruded material according to  claim 7 , wherein
 said brass alloy extruded material is produced by adding 0.2 to 2.0 wt % of graphite particles to said brass alloy powder and mixing them together, and extruding the resultant mixed powder aggregate.   
     
     
         11 . The brass alloy extruded material according to  claim 10 , wherein
 said graphite particles have a particle size of 1 μm to 100 μm.   
     
     
         12 . A brass alloy member having a brass composition formed by a mixed phase of α-phase and β-phase, containing 0.5 to 5.0 mass % of chromium, and containing at least one element selected from the group consisting of nickel, manganese, zirconium, vanadium, titanium, silicon, aluminum, and tin, wherein
 said chromium includes a component that is solid-solved in a mother phase of brass, and a component that is precipitated at crystal grain boundaries. 
 
     
     
         13 . The brass alloy member according to  claim 12 , further containing graphite particles. 
     
     
         14 . A method for producing a brass alloy extruded material, comprising the steps of:
 producing, by using a rapid solidification method, brass alloy powder having a brass composition formed by a mixed phase of α-phase and β-phase, and containing 0.5 to 5.0 mass % of chromium; and   extruding an aggregate of said rapidly solidified brass alloy powder.   
     
     
         15 . The method according to  claim 14 , wherein
 said rapid solidification method is a water atomizing method.   
     
     
         16 . The method according to  claim 14 , wherein
 a heating temperature of said extrusion process is 650° C. or less.   
     
     
         17 . The method according to  claim 14 , further comprising the step of:
 before said extrusion process, adding 0.2 to 2.0 wt% of graphite particles to said brass alloy powder and mixing them together.