... bolt, expansion screw.etc.Specialized in manufacturing fasteners such as bolts,screws,studs,nuts,washers,threaded Rods,pins,rivets,stamping,circlips ... a Research & Development Department has been established,and we canmanufacture various high quality fasteners which meet the GB, ... 1. High strength alloy steel double end stud- , fully-threaded stud and heavy hex nut applied on petrochemical industry, ...