6.1.2. Smelting processThe steel shall be treated by vacuum degassing, Ca or Si alloys are not allowed to deoxidize. 6.1.4. MacrostructureCracks, flakes, folds and porosity are not allowed when macroscopic examination. According to ASTM E 381, the qualified grade does not exceed S2, R2 and C2 (for steel bar diameter over Φ350, can not exceed C3 ), respectively. The criteria compliance with other standard specification should be confirmed with Envision. 6.1.5. Nonmetallic inclusionThe nonmetallic inclusion shall be inspected in method A in ISO 4967:1998(E). At least 6 specimens are tested for inclusions. The average value of inclusions should meet the requirements of the table below, and at least two thirds of the specimens should meet the requirements of Table 6.1.