ALEXANDRIA, Va., March 19 -- United States Patent no. 12,252,757, issued on March 18, was assigned to Furukawa Rock Drill Co. Ltd. (Tokyo).
"Drill tool and method for producing same" was invented by Yoshimi Matsumoto (Takasaki, Japan) and Genki Fusato (Takasaki, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A drill tool capable of coping with a rock drill having high output power and a method for producing the drill tool are described. The drill tool is produced by employing, as a drill tool material, an alloy steel composed of the following chemical components: 0.22 to 0.26 wt % of C, 0.15 to 0.35 wt % of Si, 0.55 to 0.80 wt % of Mn, 2.60 to 3.00 wt % of Ni, 1.00 to 1.50 wt % of Cr, 0.20 to 0.30 wt %...