Powder for grinding and grinding method

Abstract

Powder for grinding according to the present invention is powder for grinding that is manufactured according to the atomize method and serves as a medium for grinding a surface of a base substrate to form concave portions. The powder for grinding contains as its components at least one of Fe and Ni and W (tungsten) and a content of W is 30 to 55 wt % and a specific gravity thereof is equal to or higher than 8.5. Preferably, the powder for grinding further contains Cr at a content of 1 to 25 wt %. Preferably, the powder for grinding further contains B at a content of 0.5 to 4 wt %. It is possible to surely collect the powder for grinding making use of a difference between a specific gravity of the powder for grinding and a specific gravity of grinding wastes. The powder for grinding collected is suitable for being served for reuse at least once.

1 . Powder for grinding that is manufactured according to an atomize method and used for grinding a surface of a base substrate to form concave portions, the powder for grinding containing as its components at least one of Fe and Ni and W (tungsten), 
 wherein a content of W is 30 to 55 wt % and a specific gravity thereof is equal to or higher than 8.5.    
     
     
         2 . The powder for grinding as claimed in  claim 1 , wherein a total content of Fe and Ni is 25 to 70 wt %.  
     
     
         3 . The powder for grinding as claimed in  claim 1 , wherein the powder for grinding further contains Cr at a content of 1 to 25 wt %.  
     
     
         4 . The powder for grinding as claimed in  claim 3 , wherein the powder for grinding contains Fe as an essential element, and a ratio of Fe and Cr is in the range of 6:4 to 9.5:0.5 in a weight ratio.  
     
     
         5 . The powder for grinding as claimed in  claim 3 , wherein Cr is contained in the powder in the form of a passivation film which covers at least a part of the surface of a particle of the powder for grinding.  
     
     
         6 . The powder for grinding as claimed in  claim 1 , wherein the powder for grinding further contains B (boron) at a content of 0.5 to 4 wt %.  
     
     
         7 . The powder for grinding as claimed in  claim 1 , wherein a content of C (carbon) is equal to or lower than 0.8 wt %.  
     
     
         8 . The powder for grinding as claimed in  claim 1 , wherein an average particle diameter of the particles of the powder for grinding is in the range of 5 to 20 μm.  
     
     
         9 . The powder for grinding as claimed in  claim 1 , wherein the powder for grinding contains particles having a particle diameter equal to or larger than 50 μm measured by a laser particle size analyzer, the ratio of such particles is equal to or lower than 5 wt %.  
     
     
         10 . The powder for grinding as claimed in  claim 1 , wherein a tap density (defined by JPMA P08-1992 of the Japan Powder Metallurgy Association Standard) is equal to or higher than 5 g/cm 3 .  
     
     
         11 . The powder for grinding as claimed in  claim 1 , wherein the atomize method is a water atomize method.  
     
     
         12 . The powder for grinding as claimed in  claim 1 , wherein the concave portions are grooves having an average width of w (μm), and an average particle diameter of the particles of the powder for grinding is in the range of 0.07w to 0.7w (μm).  
     
     
         13 . The powder for grinding as claimed in  claim 1 , wherein the powder for grinding is served for reuse at least once.  
     
     
         14 . A grinding method of grinding a surface of a base substrate with the powder for grinding defined by  claim 1  to form concave portions on the surface.  
     
     
         15 . The grinding method as claimed in  claim 14 , wherein, after the grinding, the powder for grinding is selectively collected out of a mixture of grinding wastes and the powder for grinding left after the grinding making use of a difference between a specific gravity of the grinding wastes and a specific gravity of the powder for grinding.