Method of manufacturing a tubular product and tubular product
The present invention relates to a method for manufacturing a tubular product, characterized in that the tubular product is manufactured from steel comprising chromium in the range of 2.5 to 9.5 wt. % and silicon in an amount of more than 1.0 wt. %, and the method comprises the steps of austenitizing, quenching and tempering at a tempering temperature in the range of 300° C. to 550° C. Furthermore, the invention concerns a tubular product produced by this method.
1. Tubular product, characterized in that it is manufactured from steel comprising chromium in a range of 3-7 wt. % and silicon in an amount of more than 1.0 wt. %, and the method of manufacturing comprises the steps of austenitizing, quenching and tempering at a tempering temperature in a range of 300° C. to 550° C.
2. Tubular product according to claim 1 , characterized in that the steel consists, besides iron and unavoidable impurities, of the following alloying elements in wt. %:
C
0.05-0.3
Si
1.1-4
Mn
0.5-2.0
Cr
3-7
Al
0.01-0.1
and at least one of the following alloying elements in the specified ranges in wt. %:
Nb
0.001-0.1
V
0.001-0.2
Ti
0.001-0.1
Mo
0.001-0.7.
3. Tubular product according to claim 2 , characterized in that the manganese content is in the range of 0.5-1.0 wt. %.
4. Tubular product according to claim 2 , characterized in that the aluminum content is 0.02 wt. %.
5. Tubular product according to claim 2 , characterized in that the niobium content is 0.0175 wt. %.
6. Tubular product according to claim 1 , characterized in that the silicon content is in a the range of more than 1 wt. % and up to 4 wt. %.
7. Tubular product according to claim 1 , characterized in that an ablation of a surface is uniform in an event of corrosion.
8. Tubular product according to claim 1 , characterized in that the tubular product has a yield strength of at least 550 MPa.
9. Tubular product according to claim 1 , characterized in that the tubular product is a seamless tubular product.
10. Tubular product according to claim 1 , characterized in that the tubular product has a structure of tempered martensite with a maximum retained austenite content of 20%.
11. Tubular product according to claim 1 , characterized in that a density of carbides in the microstructure of the tubular product is below 10 22 m −3 .
12. Tubular product according to claim 1 , characterized in that a mean size of carbides in the microstructure of the tubular product is <20 nm.
13. Tubular product according to claim 1 , characterized in that the silicon content is in a range of 1.1-3 wt. %.
14. Tubular product according to claim 1 , characterized in that the silicon content is in a range of 1.5-2 wt. %.
15. Tubular product according to claim 1 , characterized in that an ablation of a surface is uniform in an event of sweet gas corrosion.
16. Tubular product according to claim 1 , characterized in that the tubular product has a yield strength of at least 1,100 MPa.
17. Tubular product according to claim 1 , characterized in that a mean size of >50% of carbides in the microstructure of a tubular product is less than 15 nm.