GB878 standard threaded cylindrical pins and slotted headless screws are high-precision positioning fasteners widely used in mechanical assembly, equipment fixing, mold processing and industrial engineering fields. Made of premium 45# steel with quenching heat treatment, these threaded pins feature high hardness, strong wear resistance and stable mechanical performance, fully complying with GB878 national standard requirements. Designed with straight slotted structure and headless thread tail design, available in complete specifications from M4, M5, M6, M8, M10 to M20. Precision machined threads ensure tight positioning, easy installation and firm locking for various assembly scenarios. With excellent durability and wide compatibility, these quenched 45# steel positioning fasteners are ideal for hardware importers, mechanical manufacturers and engineering enterprises, providing accurate and reliable positioning solutions for industrial assembly projects.