Concrete screw 1)Material:C1022,case hardened,surface hardness HV450-750,core hardness HV270-390,carbon penetration depth 0.15- Concrete screw1)Product : concrete screw2)Material: C1022, case hardened, surface hardness HV450-750, core hardness HV270-390, carbon penetration depth 0.15-0.30mm3)Sizes: 7.5x50-7.5x200 Full Thread Concrete Screw