The invention discloses an
atmosphere-
corrosion-resistant cold heading steel
hot rolled wire rod with the grade being 10.9. The
atmosphere-
corrosion-resistant cold
forging steel
hot rolled wire is composed of, by weight, 0.25-0.35% of C, 0.15-0.35% of Si, 0.60-0.90% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.60-0.90% of Cr, 0.20-0.50% of Ni, 0.20-0.50% of Cu and the balance of Fe and trace impurities. According to the
hot rolled wire rod, through the
optimal design of chemical components, and by adding
alloy elements such as Cu and Cr, a compact
amorphous metal film which is closely combined with a substrate is naturally formed on a
fastener through surface
rust in the using process, so that the material has the
atmosphere-
corrosion-resistant effect; by adding an
alloy element of Ni, the material has the good surface quality during hot rolling, the surface is free of obvious
cracking phenomenon in the subsequent drawing and cold heading processes; and the hot rolled
wire rod has the characteristics of being good in mechanical performance, corrosion resistance and
formability and the like.