4.2. Chemical Composition4.2.1. Chemical composition shall be within the acceptance limits specified by Appendix A,Table 1 when analyzed in accordance with ASTM A751.4.3. Physical PropertiesThere are no physical properties required by this specification.4.4 Mechanical PropertiesThere are no mechanical properties required by this specification.4.5. Structure4.5.1. Grain size shall be 5 or finer when measured in accordance with ASTM E112.4.6. Additional Requirements4.6.1. Hardenability shall be as specified for ASTM A304 8620H when measured inaccordance with ASTM A255.4.6.2. Material must be commercially free from seams, laps, pipe, segregation and otherdefects detrimental to machining or performance.