Method for producing special fastener

The invention discloses a fabrication method of special fastener, comprising a blank preparation, a heat treatment technology, a surface treatment technology and inspection of finish product. The invention utilizes 42CrMoA which is made in China as raw material, adopts a controllable atmosphere quenching furnace, and obtains the ideal temperature and time of quenching and tempering in heat treatment technology via massive theory instruction and test data. By strictly controlling the temperature and the time as well as carrying out the qualitative investigation of metallography and the test of entire mechanical performance, the invention can greatly strengthen the comprehensive performance of material and promote the corrosion resistance of products by coordinating with the special surface treatment technology. By examined, the special fastener which is prepared by using the invention can have the mechanical performance of 8.8/8 levels and above, the impact energy of the low temperature impact property of more than 40 Joule at minus 101 DEG C, the salt spray resistance of more than 4000 hours, and has the advantages of the high strength, the low temperature resistance and the corrosion resistance.