... -99 Material:HT200-250,Ductile. Usage:apply to all kinds of test work,and the reference plane used to measure ... -240, after two manual processing (annealing 530 degrees -620 degrees of artificial and natural aged 2-3 years) using the precision ... product , Good wear resistance.5) Precision: According to the implementation of the national standard verification procedures, namely, 0,1,2,3 ...