Low carbon steels having cold workability

Claim 2

A NON-ALUMINUM KILLED, LOW CARBON, NON-ALLOY STEEL HAVING ING COLD WORKABILITY, CONSISTING ESSENTIALLY OF UP TO 0.5% CARBON 0.05 TO 0.4% MANGANESE AND 0.05 TO 0.25% ALUMINUM, PHOSPHORUS AND SULFUR EACH NOT OVER 0.030%, SILICON NOT OVER 0.05%, 0 TO 0.01% BORON, 0 TO 0.1% EACH OF ONE OR MORE ELEMENTS SELECTED FROM THE GROUP CONSISTING OF ZICRONIUM, MOLYBDENUM AND VANADIUM, BALANCE IRON EXCEPT FOR INCIDENTAL IMPURITIES, NOT MORE THAN 25 PPM OF NITROGEN AND 35 PPM OF OXYGEN, SUBSTANTIAL FREEDOM FROM HARD OXIDE INCLUSIONS, AND THE PRESENCE OF THE AFORESAID ALUMINUM SUBSTANTIALLY ALL IN METALLIC STATE RATHER THAN APPRECIABLY IN COMBINED STATE THAT OCCURS AFTER USE OF ALUMINUM FOR KILLING, SO THAT SAID COMPOSITION AND CHARACTERISTICS PROVIDE IMPROVED COLD WORKABILITY OF THE STEEL IN AT LEAST ONE OF THE RESPECTS OF REDUCED COLD WORK HARDENING AND OF AVOIDANCE OF CRACKING ON COMPRESSIVE COLD DEFORMATION, IN COMPARISON WITH LOW CARBON NON-ALLOY, ALUMINUM-KILLED STEELS.

Claim 3

A steel as defined in claim 1, in which silicon is not over 0.15%.

Claim 4

A steel as defined in claim 1, in which the carbon is not over 0.25%, manganese is 0.05 to 0.25%, and aluminum is not over 0.15%.

Claim 5

A steel as defined in claim 3, in which silicon is not over 0.15%.

Claim 6

A steel as defined in claim 4, in which phosphorus and sulfur are each not over 0.025% and nitrogen and oxygen are not more than 25 ppm and 35 ppm respectively.

Claim 7

A steel as defined in clAim 1, in which carbon is 0.01 to 0.15% and aluminum is 0.05 to 0.12%.

Claim 8

A steel as defined in claim 1, in which carbon is 0.15% to 0.25% and aluminum is 0.08 to 0.15%.

Claim 9

A steel as defined in claim 1, in which carbon is 0.25% to 0.5% and aluminum is at least 0.12%.

Claim 10

A non-aluminum killed low carbon, non-alloy steel having cold workability, consisting essentially of up to 0.2% carbon, 0 to 0.2% manganese, and 0.05 to 0.15% aluminum, phosphorus and sulfur each not over 0.025%, silicon not over 0.15%, 0 to 0.15% boron, 0 to 0.1% each of one or more elements selected from the group consisting of zirconium, molybdenum and vanadium, nitrogen and oxygen not over 25 ppm and 35 ppm respectively, and balance iron except for incidental impurities, said aluminum being present substantially all in metallic state rather than in combined state that occurs after use of aluminum for killing, said steel being sufficiently characterized by not more thn low content of manganese, not more than said low contents of nitrogen and oxygen, substantial freedom from hard oxide inclusions, and said aluminum in metallic state only, so that said composition and characteristics provide improved cold workability of the steel in at least one of the respects of reduced work hardening and reduced tendency to cracking on compressive cold deformation, in comparison with low-carbon, non-alloy, aluminum-killed steel.

Claim 11

A non-aluminum killed low carbon, non-alloy steel having cold workability, consisting essentially of up to 0.2% carbon, 0 to 0.2% manganese, and 0.05 to 0.15% aluminum, phosphorus and sulfur each not over 0.025%, silicon not over 0.15%, 0 to 0.15% boron, 0 to 0.1% each of one or more elements selected from the group consisting of zirconium, molybdenum and vanadium, nitrogen and oxygen not over 25 ppm and 35 ppm respectively, and balance iron except for incidental impurities, said aluminum being present substantially all in metallic state rather than in combined state that occurs after use of aluminum for killing, said steel being sufficiently characterized by not more thn low content of manganese, not more than said low contents of nitrogen and oxygen, substantial freedom from hard oxide inclusions, and said aluminum in metallic state only, so that said composition and characteristics provide improved cold workability of the steel in at least one of the respects of reduced work hardening and reduced tendency to cracking on compressive cold deformation, in comparison with low-carbon, non-alloy, aluminum-killed steel.

Claim 12

A steel as defined in claim 9, in which carbon is not over 0.15%, silicon is not over 0.05%, and nitrogen and oxygen are not over 20 ppm and 30 ppm respectively.

Claim 13

A steel as defined in claim 2, in which carbon is not over 0.25%, manganese not over 0.25%, phosphorus not over 0.025%, sulfur not over 0.02%, and aluminum not over 0.20%, and oxygen is not more than 30 ppm.

Claim 14

A steel as defined in claim 11, in which silicon is not over 0.05%, aluminum not over 0.15% and nitrogen is present at not more than 20 ppm.