COMPACT STRIP OR THIN SLAB PROCESSING OF BORON/TITANIUM STEELS

• US 20100136363A1
• Filed: 11/25/2009
• Published: 06/03/2010
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Maverick Tube Corporation (Tenaris SA), Ternium Mexico SA de CV (Ternium Internacional España Sl)
• Original Assignee: Maverick Tube Corporation (Tenaris SA), Ternium Mexico SA de CV (Ternium Internacional España Sl)
• Inventors: Valdez, Martin Emiliano, Actis, Fernando Augusto, Garcia, Marco Antonio Herrera, Puente Sireno, Gerardo
• Granted Patent: US 8,221,562 B2
• Time in Patent Office: Days
• US Class Current: 428/586
• CPC Class Codes: B22D 11/111 by using protecting powders
• CPC Class Codes: C22C 38/04 containing manganese
• CPC Class Codes: C22C 38/14 containing titanium or zirconium
• CPC Class Codes: Y02P 10/20 Recycling
• CPC Class Codes: Y10T 428/12292 Workpiece with longitudinal passageway or stopweld material [e.g., for tubular stock, etc.]

Abstract

A method for casting medium carbon, B/Ti steel product using compact strip processing or thin slab casting. The method can include providing a steel composition including boron and titanium and casting the steel composition into a slab having a thickness between about 25 and 150 mm. The slab can have a cast composition including about 0.23 to 0.30 wt. % carbon, about 0.0010 to 0.0050 wt. % boron, about 0.010 to 0.050 wt. % titanium, about 1.15 to 1.50 wt. % manganese, less than 0.35 wt. % silicon and a Ti/N ratio greater than 2.9. The amount of each element is provided based upon the total weight of the steel composition. The steel slab can be free from cracks and significant defects. Furthermore, the steel slab can be used for electric resistance welded (ERW) products.

Claims

1. A method of manufacturing a steel product, comprising:

providing a steel composition comprising boron and titanium;

casting the steel composition into a slab having a thickness between about 25 and 150 mm, wherein the slab has a cast composition comprising;

about 0.23 to 0.30 wt. % carbon;

about 0.001 to 0.005 wt. % boron;

about 0.010 to 0.050 wt. % titanium;

about 1.15 to 1.50 wt. % manganese;

less than about 0.35 wt. % silicon;

a Ti/N ratio greater than about 2.9; and

wherein the amount of each element is provided based upon the total weight of the cast composition.

2. The method of claim 1, wherein the cast composition further comprises about 0.010 to 0.070 wt. % aluminum.

3. The method of claim 1, wherein the cast composition comprises about 0.001 to 0.005 wt. % free boron.

4. The method of claim 1, wherein the cast composition consists essentially of:

about 0.23 to 0.30 wt. % carbon;

about 0.001 to 0.005 wt. % boron;

about 0.010 to 0.050 wt. % titanium;

about 1.15 to 1.50 wt. % manganese;

less than about 0.35 wt. % silicon; and

the balance being iron and incidental impurities; and

wherein the amount of each element is provided based upon the total weight of the cast composition; and

wherein a Ti/N ratio is greater than about 2.9.

5. The method of claim 1, wherein the cast composition comprises:

about 0.23 to 0.29 wt. % carbon;

about 0.001 to 0.005 wt. % boron;

about 0.010 to 0.045 wt. % titanium;

about 1.15 to 1.50 wt. % manganese;

less than about 0.35 wt. % silicon;

less than about 0.025 wt. % phosphorus;

less than about 0.01 wt. % sulfur;

about 0.010 to 0070 wt. % aluminum;

less than about 0.010 wt. % nitrogen;

less than about 0.2 wt. % nickel;

less than about 0.2 wt. % chromium;

less than about 0.11 wt. % molybdenum;

less than about 0.01 wt. % vanadium;

less than about 0.01 wt. % niobium;

less than about 0.005 wt. % calcium;

less than about 0.25 wt. % copper;

less than about 0.02 wt. % tin;

a Ti/N ratio greater than about 2.9; and

wherein the amount of each element is provided based upon the total weight of the cast composition.

6. The method of claim 1, wherein the thickness of the slab is about 30 to 100 mM.

7. The method of claim 1, wherein the width of the slab is about 915 to 1370 mM.

8. The method of claim 1, wherein the casting the steel composition into a slab is done at a rate of up to about 4.3 m/min.

9. The method of claim 1, wherein the casting the steel composition into a slab is done at a rate of about 3.8 to 6 m/min.

10. The method of claim 1, wherein the casting the steel composition into a slab is done at a rate of about 1.5 to 3.5 ton/min.

11. The method of claim 1, wherein casting the steel composition comprises:

transporting the steel composition into a tundish;

maintaining the steel composition at a temperature of about 1510 to 1595°

C. in a tundish;

flowing the steel composition from the tundish through a nozzle and into a water-cooled mold; and

exiting the slab from the mold.

12. The method of claim 1, wherein casting the steel composition further comprises adding a mold powder to the steel composition;

and wherein the mold powder comprises calcium aluminate.

13. The method of claim 12, wherein the mold powder substantially does not remove titanium from the steel composition.

14. The method of claim 1, further comprising forming the slab into a pipe.

15. The method of claim 14, wherein forming the slab into a pipe comprises a welding operation.

16. A steel product manufactured according to the method of claim 1.

17. A welded steel pipe comprising:

a cast composition comprising;

about 0.23 to 0.30 wt. % carbon;

about 0.001 to 0.005 wt. % boron;

about 0.010 to 0.050 wt. % titanium;

about 1.15 to 1.50 wt. % manganese;

less than about 0.35 wt. % silicon;

a Ti/N ratio greater than about 2.9; and

wherein the amount of each element is provided based upon the total weight of the cast composition

wherein the steel pipe is formed from a thin cast slab having a thickness between about 25 to 150 mm.

18. The welded steel pipe of claim 17, wherein the cast composition further comprises about 0.010 to 0.070 wt. % aluminum.

19. The welded steel pipe of claim 17, wherein the cast composition consists essentially of:

about 0.23 to 0.30 wt. % carbon;

about 0.001 to 0.005 wt. % boron;

about 0.010 to 0.050 wt. % titanium;

about 1.15 to 1.50 wt. % manganese;

about 0.010 to 0.070 wt. % aluminum less than about 0.35 wt. % silicon; and

the balance being iron and impurities;

wherein the amount of each element is provided based upon the total weight of the cast composition; and

wherein a Ti/N ratio is greater than about 2.9.

20. The welded steel pipe of claim 17, wherein the cast composition comprises:

about 0.23 to 0.29 wt. % carbon;

about 0.001 to 0.005 wt. % boron;

about 0.010 to 0.045 wt. % titanium;

about 1.15 to 1.50 wt. % manganese;

less than 0.35 wt. % silicon;

less than 0.025 wt. % phosphorus;

less than 0.01 wt. % sulfur;

about 0.010 to 0070 wt. % aluminum;

less than 0.010 wt. % nitrogen;

less than 0.2 wt. % nickel;

less than 0.2 wt. % chromium;

less than 0.11 wt. % molybdenum;

less than 0.01 wt. % vanadium;

less than 0.01 wt. % niobium;

less than 0.005 wt. % calcium;

less than 0.25 wt. % copper;

less than 0.02 wt. % tin;

a Ti/N ratio greater than 2.9; and

wherein the amount of each element is provided based upon the total weight of the cast composition.