... : C1022, case hardened, surface hardness HV450-750, core hardness HV27 Window Frame Screw1) Application: it is for the installation of windows ... -U, wood or aluminium, as well as frame couplings and brackets. Window frame screws tap directly into brickwork, doing away with the ... , 152mm, 182mm, 202mm, 212mm 4) Coating: Zinc, Yellow Zinc Concrete Window Frame Screw