... .8,8.8..... Special Fastener,Special Fasteners,Special Nuts Bolts Screw Fasteners. 1.What’s the specification of our Products ? MaterialCarbon ... iron,such as 1022,1018,1010,1008,1015...Medium carbon steel are 35k,45#,10B21,1035,CH38F,1039,40ACR...Alloy steel are ... a professional manufacturer with more than 20 years experiences in screw,bolt,nut,washer,rivet, stud, pin,wrench and so on ...