x45crsi93 Size:4.8mm--12.7mm 20 years engine valve steel factory ISO certification x45crsi93 Size:4.8mm--12.7mm20 years engine valve steel factoryISO certificationSpecificationDiameter: 4.8mm—12.7mmMaterial GradeGB40Cr10Si2Mo, 42Cr9Si2, 45Cr9Si3, 51Cr8Si2,80Cr20Si2Ni, 85Cr18Mo2V, 86Cr18W2VRe, 20Cr21Ni12N, 33Cr23Ni8Mn3N, 45Cr14Ni14W2Mo, 50Cr21Mn9Ni4Nb2WN, 53Cr21Mn9Ni4N, 55Cr21Mn8Ni2N, ...