As-worked, heat treated cold-workable hypoeutectoid steel

Abstract

Hypoeutectoid steels are worked within a temperature range of between the A 1 temperature to 150° F. below the A 1 temperature. The cross-sectional area of the steels is reduced by not less than 60% during working. After working, the steels can be heated to about the A 1 temperature to obtain the optimum hardness and ductility for cold-working. The as-worked structure and the heat treated structure are also described.

I claim: 
     
       1. A heat treated hypoeutectoid steel consisting essentially of about 0.30 to about 0.80% carbon and the remainder iron and incidental impurities characterized by having good formability and a microstructure comprising fine well-dispersed spheroidal carbides having a size of .[.not more than 0.3.]. .Iadd.about 0.5 to 2.5 .Iaddend.microns in a ferritic matrix, said ferritic matrix being free of lamellar carbides and having a grain size of about three microns to about ten microns. 
     
     
       2. An as-worked hypoeutectoid steel characterized by having high strength and good ductility, said steel consisting essentially of about 0.30 to about 0.80% carbon and the remainder iron and incidental impurities having a microstructure comprising finely-divided well-dispersed spheroidal carbides in a fine-grain ferritic matrix, said carbides being not more than 1 micron in size and said ferritic matrix having a grain size of not more than 1.5 microns.