... internal quality:Flaw detection to meet the grade I standard JB/T4730,GB/T2970 and SEL072, EN10160 standard S3T4,ASTM,A578 ... , grade C and grade I standard jb/t8467, and grade I standard gb/t6402, to reach the ... internal quality:Flaw detection to meet the grade I standard JB/T4730,GB72790 ASTM,A435, A578, JISG0801, JISG0901, sel072, NFA04305,3 ...