RU2003112631A

RU2003112631A - METHOD FOR PRODUCING A STEEL STRIP

Info

Publication number: RU2003112631A
Application number: RU2003112631/02A
Authority: RU
Inventors: Лазар Стрезов; Каннаппар МУКУНТХАН; Уолтер БЛЕДЖД; Рама МАХАПАТРА
Original assignee: Ньюкор Корпорейшн
Priority date: 2000-10-02
Filing date: 2001-09-28
Publication date: 2004-12-20

Claims

1. A method of manufacturing a steel strip, comprising the steps of:

(a) carry out continuous casting of molten steel to obtain a strip, and

(b) cooling the strip within the temperature range of the conversion of austenite to ferrite,

characterized in that the concentration of residual impurities in the composition of the steel is selected in connection with the microstructure of the strip, which is necessary to ensure the required mechanical properties.

2. The method according to claim 1, characterized in that the total amount of residual impurities is 2.0 wt.% Or less.

3. The method according to claim 1, characterized in that the total amount of residual impurities is 1.2 wt.% Or less.

4. The method according to any one of the preceding paragraphs, characterized in that the cast strip obtained in step (a) has a thickness of not more than 2 mm.

5. The method according to any one of the preceding paragraphs, characterized in that the cast strip obtained in step (a) contains austenitic grains that are columnar.

6. The method according to any one of the preceding paragraphs, characterized in that the steel is a low carbon steel.

7. The method according to claim 6, characterized in that the low carbon steel is steel deoxidized by silicon / manganese.

8. The method according to claim 7, characterized in that the steel, deoxidized by silicon / manganese, contains in mass percent:

9. The method according to any one of claims 1 to 6, characterized in that the low carbon steel is steel, deoxidized by aluminum.

10. The method according to claim 9, characterized in that the low-carbon steel, deoxidized by aluminum, has the following composition, expressed in mass percent:

11. The method according to any one of the preceding paragraphs, characterized in that the continuous casting machine is a twin roll casting machine.

12. The method according to any one of the preceding paragraphs, characterized in that it further includes the step of in-line hot rolling of the cast strip after step (a) before step (b).

13. The method according to any one of the preceding paragraphs, characterized in that step (b) includes cooling the cast strip to convert austenite to ferrite in the strip in the temperature range between 850 ° C and 400 ° C with a selected cooling rate of at least 0.01 ° C / sec to obtain a microstructure that provides the desired yield strength of the cast strip, and this microstructure is selected from the group including:

(i) predominantly polygonal ferrite;

(ii) a mixture of polygonal ferrite and low temperature conversion products; and

(iii) predominantly low temperature conversion products.

14. The method according to item 13, characterized in that the cooling rate is selected so that the microstructure is either (ii) a mixture of polygonal ferrite and low-temperature transformation products, or (iii) mainly low-temperature transformation products.

15. Cast steel strip made by steps:

(a) continuously casting molten steel to form a strip containing austenitic grains, said molten steel having a concentration of residual impurities selected in connection with the microstructure of the final strip, which is necessary to provide the desired yield strength, and

(b) cooling the strip to convert austenite to ferrite in the strip in the temperature range between 850 ° C. and 400 ° C.

16. The cast steel strip according to clause 15, in which the total amount of residual impurities is 2.0 wt.% Or less.

17. Cast steel strip according to clause 15, in which the total amount of residual impurities is 1.2 wt.% Or less.

18. Cast steel strip according to any one of paragraphs.15-17, which upon receipt in stage (a) contains austenitic grains, which are columnar.

19. A cast steel strip according to any one of claims 15-18, wherein the steel is a low carbon steel.

20. The cast steel strip of claim 19, wherein the low carbon steel is silicon / manganese deoxidized steel.

21. The cast steel strip according to claim 20, in which the steel, deoxidized by silicon / manganese, contains in mass percent:

22. Cast steel strip according to claim 19, in which the low carbon steel is steel, deoxidized by aluminum.

23. Cast steel strip according to item 22, in which steel, deoxidized by aluminum, has the following composition, expressed in mass percent:

24. Cast steel strip according to any one of paragraphs.15-23, which includes the step of in-line hot rolling of the cast strip after step (a) before step (b).

25. The cast steel strip according to any one of claims 15-24, wherein step (b) includes cooling the strip to convert austenite to ferrite in the strip with a selected cooling rate of at least 0.01 ° C / sec to obtain a microstructure , which provides the required yield strength of the cast strip, and this microstructure is selected from the group including:

(i) predominantly polygonal ferrite;

(iii) predominantly low temperature conversion products.

26. The cast steel strip of claim 25, wherein the cooling rate is selected so that the microstructure is either (ii) a mixture of polygonal ferrite and low-temperature transformation products, or (iii) mainly low-temperature transformation products.