4.5　Bolting Materials

4.5.1　Steel standards and allowable stress values of bolting materials shall meet the requirements in Table 4.5.1.

Table 4.5.1　Allowable stress values of bolting materials

Note:Interpolation may be made for intermediate temperatures.

4.5.2　Hardness of bolts shall be slightly higher than that of nuts.This may be obtained by selecting the materials with different strength or selecting different heat treatment specification.