ASTM A29 specification is standard specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements. There are following kind of carbon and alloy steel bars under this standard: hot rolled carbon steel bar, cold finished carbon steel bars, hot rolled alloy steel bars, cold finished alloy steel bars.
Carbon steel bar steel grades like 1020, 1045, 1050 etc. And alloy steel bar common steel grades like 4140, 4340, 5140 etc.
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.
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.