Improvements in gauge tools of steel capable of hardening

摘要

491,939. Hardening gauges. ZEISS, C., [Firm of]. Dec. 3, 1936, No. 33128. Void. Convention date, Dec. 9, 1935. [Class 72] [Also in Group XIX] In a gauge made of hardenable steel, the main body a of the tool is of martensite of a hardness greater than 25 and less than 65 Rockwell C units, and the working surface b of thin layers of martensite, these being preferably separated from the body a by thin layers d of pearlite. The tool is produced by hardening the tool throughout in the usual manner, tempering at 150-600‹ C. and then hardening the thin layers of the surface b which are then aged at temperatures less than 200‹ C. The thin layer of pearlite is produced by quenching, after hardening, layers of a thickness smaller than that of the previously-heated layer.