Steel, sheet steel with excellent machinability and its manufacturing process by electric steel furnace and vacuum degassing

摘要

Steel having excellent workability and deep drawability is produced by an electric furnace-vacuum degassing process. The steel has a composition which comprises about: C: 0.0050 wt% or less Si: 1.5 wt% or less Mn: 1.5 wt% or less P: 0.10 wt% or less Al: 0.10 wt% or less S: 0.020 wt% or less O: 0.01 wt% or less Cu: 1.5 wt% or less Ni: 2.0 wt% or less Ti and/or Nb: from 0.001 to 0.10 wt% N: from 0.0040 to 0.0090 wt%. Despite the presence of tramp elements such as Cu and Ni which are included during melting of iron scrap in the electric furnace, the product steel exhibits superior workability, in particular deep drawability. Disclosed also are steel sheets having excellent workability and methods of producing such steel and steel sheets. IMAGE