AISI 6150 steel is chromium vanadium type spring steel. It’s a similar alloy steel to 5150 steel with small, but effective, vanadium addition, to import greater hardness.
JIS S50C Carbon Steel is one steel grade material in JIS G4051. S50C carbon steel are generally use to make mechanical parts, like spring, gear, tension bar, the roller, the axis, the load spindle etc.
Steel C45 Round Bar is an unalloyed medium carbon steel, which is also a general carbon engineering steel. C45 is a medium strength steel with good machinability and excellent tensile properties. C45 round bar steel is equivalent to BS 970 EN8 or 080M40.