SEAMLESS STEEL PIPE FOR USE AS VERTICAL WORK-OVER SECTIONS
First Claim
1. A seamless steel tube for work-over risers comprising in weight percent, carbon 0.25-0.28, manganese 0.48-0.58, silicon 0.20-0.30, chromium 1.05-1.15, molybdenum 0.80-0.83, nickel 0.10 max, nitrogen 0.008 max, boron 0.0016-0.0026, aluminum 0.015-0.045, sulfur 0.0030 max, phosphorus 0.010 max, titanium 0.016-0.026, niobium 0.025-0.030, copper 0.10 max, arsenic 0.020 max, calcium 0.0040 max, tin 0.015 max, hydrogen 2.0 ppm max, the remainder being iron and inevitable impurities;
- and a geometry in which ends of the tube have an increased wall thickness and outer diameter and having a yield strength of at least 620 MPa (90 ksi) throughout the whole length of a tube body and in tube ends.
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Abstract
The present invention describes a seamless steel tube for work-over risers comprising in weight percent, carbon 0.23-0.29, manganese 0.45-0.65, silicon 0.15-0.35, chromium 0.90-1.20, molybdenum 0.70-0.90, nickel 0.20 max, nitrogen 0.010 max, boron 0.0010-0.0030, aluminum 0.010-0.045, sulfur 0.005 max, phosphorus 0.015 max, titanium 0.005-0.030, niobium 0.020-0.035, copper 0.15 max, arsenic 0.020 max, calcium 0.0040 max, tin 0.020 max, hydrogen 2.4 ppm max, the rest are iron and inevitable impurities, consisting of a geometry in which ends of the tube have an increased wall thickness and outer diameter and having a yield strength of at least of 620 MPa (90 ksi) throughout the whole length of a tube body and in tube ends. The present invention also describes methods for manufacturing a seamless steel tube for work-over risers having a yield strength at least of 620 MPa (90 ksi) both in a tube body and in tube ends.
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Citations
19 Claims
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1. A seamless steel tube for work-over risers comprising in weight percent, carbon 0.25-0.28, manganese 0.48-0.58, silicon 0.20-0.30, chromium 1.05-1.15, molybdenum 0.80-0.83, nickel 0.10 max, nitrogen 0.008 max, boron 0.0016-0.0026, aluminum 0.015-0.045, sulfur 0.0030 max, phosphorus 0.010 max, titanium 0.016-0.026, niobium 0.025-0.030, copper 0.10 max, arsenic 0.020 max, calcium 0.0040 max, tin 0.015 max, hydrogen 2.0 ppm max, the remainder being iron and inevitable impurities;
- and a geometry in which ends of the tube have an increased wall thickness and outer diameter and having a yield strength of at least 620 MPa (90 ksi) throughout the whole length of a tube body and in tube ends.
- View Dependent Claims (2, 3, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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4. A method for manufacturing a seamless steel tube for work-over risers having a yield strength at least of 620 MPa (90 ksi) both in a tube body and in tube ends comprising the following steps of:
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(a) providing a steel tube comprising a composition in weight percent, carbon 0.23-0.29, manganese 0.45-0.65, silicon 0.15-0.35, chromium 0.90-1.20, molybdenum 0.70-0.90, nickel 0.20 max, nitrogen 0.010 max, boron 0.0010-0.0030, aluminum 0.010-0.045, sulfur 0.005 max, phosphorus 0.015 max, titanium 0.005-0.030, niobium 0.020-0.035, copper 0.15 max, arsenic 0.020 max, calcium 0.0040 max, tin 0.020 max, hydrogen 2.4 ppm max, the rest are iron and inevitable impurities; (b) upsetting of tube ends; (c) austenitizing between 850-930°
C. the full length of the tube; and(d) quenching and tempering between 630-720°
C. - View Dependent Claims (5, 18)
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6. A method for manufacturing a seamless steel tube for work-over risers having a yield strength at least of 620 MPa (90 ksi) both in a tube body and in tube ends comprising the following steps of:
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(a) providing a steel tube comprising a composition in weight percent, carbon 0.23-0.29, manganese 0.45-0.65, silicon 0.15-0.35, chromium 0.90-1.20, molybdenum 0.70-0.90, nickel 0.20 max, nitrogen 0.010 max, boron 0.0010-0.0030, aluminum 0.010-0.045, sulfur 0.005 max, phosphorus 0.015 max, titanium 0.005-0.030, niobium 0.020-0.035, copper 0.15 max, arsenic 0.020, calcium 0.0040 max, tin 0.020 max, hydrogen 2.4 ppm max, the rest are iron and inevitable impurities, obtained by rolling process (MPM process); (b) heat treating the tube comprising austenitizing between 850-930°
C. the full length of the tube, and quenching and tempering between 630-720°
C.;(c) destructive testing including microcleanliness, austenitic grain size, calculate % of martensitic transformation, tensile, hardness, toughness, sulfide stress cracking (SSC) testing; (d) dimensional controlling of pipe body including one or more of outer diameter (OD), out of roundness, straightness, inner diameter (ID), and length; and (e) machining from external surface the complete length of the pipe by programming CNC lath machine in order to achieve final dimensions at the ends. - View Dependent Claims (7, 19)
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Specification