The hardness of the highest purity grade of industrial pure titanium/pure titanium bolt is usually less than 120 (Brinell), and the hardness of other industrial pure titanium is 200 to 295 (Brinell). The hardness of pure titanium castings is 200~220(Brinell). The hardness value of titanium alloy/titanium alloy bolt in the annealed state is 32~38 (Rockwell. C calibration), equivalent to 298~349 Brinell hardness. The hardness of Ti-5Al-2.5Sn and Ti-6AlIV as cast is 320 (Brinell), and the hardness of Ti-6Al-4V castings with low clearance impurities is 310 (Brinell).