Seamless steel tube resistant to carbon dioxide corrosion and manufacturing method therefor

Abstract

Disclosed in the present application is a high-strength seamless steel tube resistant to carbon dioxide corrosion. In addition to containing Fe and inevitable impurities, the seamless steel tube comprises the following chemical elements in mass percentage: C: 0.05-0.18%, Si: 0.15-0.40%, Mn: 0.25-0.50%, Cr: 4.0-6.0%, Mo: 0.08-0.35%, Al: 0.020-0.055%, Ca: 0.001-0.004%; and one or more elements selected from Ti, Nb, V, Ce, and La, wherein 0.003%≤Ti+Nb+V+Ce+La≤0.20%. Also disclosed in the present application is a manufacturing method for the seamless steel tube. The method comprises the following steps: (1) manufacturing a tube billet; (2) subjecting the tube billet to heating, perforating, hot rolling, and sizing to obtain a hot-rolled tube; and (3) subjecting the hot-rolled tube to a quenching and tempering heat treatment: quenching within a temperature range of 860-940° C. for 15-120 min, and then tempering within a temperature range of 520-620° C. for 30-150 min.

1 . A seamless steel tube resistant to corrosion by carbon dioxide, comprising the following chemical elements in mass percentage, in addition to containing Fe and inevitable impurities:
 C: 0.05-0.18%, Si: 0.15-0.40%, Mn: 0.25-0.50%, Cr: 4.0-6.0%, Mo: 0.08-0.35%, Al: 0.020-0.055%, Ca: 0.001-0.004%; and one or more selected from Ti, Nb, V, Ce, and La, wherein 0.003%≤Ti+Nb+V+Ce+La≤0.20%.   
     
     
         2 . The seamless steel tube according to  claim 1 , wherein the seamless steel tube consists of the following chemical elements in mass percentage:
 C: 0.05-0.18%, Si: 0.15-0.40%, Mn: 0.25-0.50%, Cr: 4.0-6.0%, Mo: 0.08-0.35%, Al: 0.020-0.055%, Ca: 0.001-0.004%; and one or more selected from Ti, Nb, V, Ce, and La, wherein 0.003%≤Ti+Nb+V+Ce+La≤0.20%, and the balance of Fe and inevitable impurities.   
     
     
         3 . The seamless steel tube according to  claim 1 , wherein the content of the chemical elements in the seamless steel tube further satisfy at least one of the following:
 C: 0.09-0.15%,   Si: 0.2-0.35%,   Mn: 0.3-0.45%,   Cr: 4.5-5.5%,   Mo: 0.1-0.25%,   Al: 0.025-0.045%,   Ca: 0.0015-0.003%, and   0.005%≤Ti+Nb+V+Ce+La≤0.15%.   
     
     
         4 . The seamless steel tube according to  claim 1 , wherein among the inevitable impurities, P≤0.015%, S≤0.008%, N≤0.006%, and O≤0.0035%. 
     
     
         5 . The seamless steel tube according to  claim 4 , wherein among the inevitable impurities, P≤0.012%, S≤0.005%, N≤0.0045%, and O≤0.002%. 
     
     
         6 . The seamless steel tube according to  claim 1 , having a tempered sorbite structure. 
     
     
         7 . The seamless steel tube according to  claim 1 , wherein the properties of the seamless steel tube satisfy at least one of the following:
 yield strength Rp0.2≥550 MPa, tensile strength Rm≥670 MPa, elongation A50≥15%, and impact property KV8≥60 J;   under the dynamic corrosion environment conditions of 60-90° C., 0.5 MPa CO 2 , 50,000 ppm Cl − , and 1 m/s, a weight loss corrosion rate is less than 0.08 mm/d, and a pitting corrosion rate is less than 0.2 mm/d.   
     
     
         8 . A manufacturing method for the seamless steel tube resistant to carbon dioxide corrosion according to  claim 1 , wherein the manufacturing method excludes a spheroidizing annealing step and comprises the following steps:
 (1) manufacturing a tube billet;   (2) subjecting the tube billet to heating, perforating, hot rolling, and sizing to obtain a hot-rolled tube; and   (3) subjecting the hot-rolled tube to quenching and tempering heat treatment: quenching the hot-rolled tube in a temperature range of 860-940° C. and holding for 15-120 min, followed by tempering the quenching tube in a temperature range of 520-620° C. and holding for 30-150 min.   
     
     
         9 . The manufacturing method according to  claim 8 , wherein in the heating step of step (2), the tube billet is heated at 1180-1280° C. and held for 120-350 min. 
     
     
         10 . The manufacturing method according to  claim 8 or 9 , wherein in step (2), perforating, hot rolling, and sizing are performed in a temperature range of 1160-1260° C. 
     
     
         11 . The seamless steel tube according to  claim 2 , wherein the content of the chemical elements in the seamless steel tube further satisfy at least one of the following:
 C: 0.09-0.15%,   Si: 0.2-0.35%,   Mn: 0.3-0.45%,   Cr: 4.5-5.5%,   Mo: 0.1-0.25%,   Al: 0.025-0.045%,   Ca: 0.0015-0.003%, and   0.005%≤Ti+Nb+V+Ce+La≤0.15%.   
     
     
         12 . The seamless steel tube according to  claim 2 , wherein among the inevitable impurities, P≤0.015%, S≤0.008%, N≤0.006%, and O≤0.0035%. 
     
     
         13 . The seamless steel tube according to  claim 2 , having a tempered sorbite structure. 
     
     
         14 . The seamless steel tube according to  claim 2 , wherein the properties of the seamless steel tube satisfy at least one of the following:
 yield strength Rp0.2≥550 MPa, tensile strength Rm≥670 MPa, elongation A50≥15%, and impact property KV8≥60 J;   under the dynamic corrosion environment conditions of 60-90° C., 0.5 MPa CO 2 , 50,000 ppm Cl − , and 1 m/s, a weight loss corrosion rate is less than 0.08 mm/d, and a pitting corrosion rate is less than 0.2 mm/d.   
     
     
         15 . The manufacturing method according to  claim 9 , wherein in step (2), perforating, hot rolling, and sizing are performed in a temperature range of 1160-1260° C.