Method for manufacturing superior 13Cr friction-welded drillrod

Abstract

The present invention provides a method for manufacturing a superior 13Cr friction-welded drillrod, the method comprising the following steps: manufacturing a superior 13Cr tube body; manufacturing a superior 13Cr internally threaded coupler and a superior 13Cr externally threaded coupler, respectively; connecting the superior 13Cr internally threaded coupler and the superior 13Cr externally threaded coupler respectively to the two ends of the superior 13Cr tube body by means of frictional butt welding; after heating seam areas to 950 C.-1000 C., cooling same to below 200 C. by ejecting compressed air onto the surfaces of the seam areas, and then cooling the seam areas to room temperature by spraying water; and tempering the seam areas by heating same to 640 C.-700 C. By the present method, a superior 13Cr friction-welded drillrod can be manufactured, which, in the case of the exploration of a gas filed containing a relatively high level of CO2, can be not only used as a drillrod in an earlier stage of nitrogen well-drilling operation, but also used as an oil tube in a later stage of well completion with oil tube.

Claims

1. A method for manufacturing a 13Cr friction-welded drillrod, the method comprising: a) manufacturing a 13Cr tube body having two opposing ends; b) manufacturing a 13Cr internally threaded coupler and a 13Cr externally threaded coupler, respectively; c) connecting the 13Cr internally threaded coupler and the 13Cr externally threaded coupler respectively to the two opposing ends of the 13Cr tube body; d) heating seam areas between the coupler and tube ends to 950 C.-1000 C.; e) cooling the heated seam areas to below 200 C.; f) cooling the seam areas to room temperature; and g) tempering the seam areas by heating the seam areas to 640 C.-700 C.

2. The method of claim 1, wherein the 13Cr tube body, 13Cr internally threaded coupler and 13Cr externally threaded coupler comprise 0.01%-0.05 wt % carbon (C), 0.5 wt % silicon (Si), 0.2%-1.0 wt % manganese (Mn), 12%-14 wt % chromium (Cr), 1%-3 wt % molybdenum (Mo); 4%-6 wt % nickel (Ni), and a balance of iron (Fe) and other impurities.

3. The method of claim 1, wherein the step of manufacturing a 13Cr tube body comprises manufacturing a tube body having two opposing ends; thickening the opposing ends of the tube body to obtain a tube body with thickened tube ends; heating the thickened tube body; cooling the thickened tube body; and tempering the thickened tube body.

4. The method of claim 3, wherein the temperature for thickening the tube ends ranges from 1150 C.-1200 C.

5. The method of claim 3, wherein the tube body is heated to 950 C.-1000 C.

6. The method of claim 3, wherein air is used as a cooling medium for cooling the tube body.

7. The method of claim 3, wherein oil is used as a cooling medium for cooling the tube body.

8. The method of claim 3, wherein the temperature for tempering the tube body is 600 C.-650 C.

9. The method of claim 1, wherein the steps of manufacturing a 13Cr internally threaded coupler and a 13Cr externally threaded coupler both comprise manufacturing a blank; forging the blank; heating the forged blank to a temperature ranging from 600 C.-700 C. for a stress-relief annealing; quenching the heated blank; and tempering the quenched blank.

10. The method of claim 9, wherein the quenching is an oil quenching and the quenching temperature ranges from 950 C.-1000 C.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The method for manufacturing a superior 13Cr friction-welded drillrod according to the present invention is described below in more details, in conjunction with particular embodiments.

Embodiments 1-5

(2) A superior 13Cr friction-welded drillrod is manufactured in the following steps:

(3) (1) manufacturing a superior 13Cr tube body:

(4) (1a) obtaining a tube body, with the composition formulation of the tube body being controlled to be C 0.01%-0.05%, Si0.5%, Mn 0.2%-1.0%, Cr 12%-14%, Mo 1%-3%, Ni 4%-6%, and a balance of Fe and inevitable impurities (the composition formulations for embodiment 1-5 are shown in table 1);

(5) (1b) thickening the ends of the tube body to obtain a tube body with thickened ends, with the temperature for thickening the tube ends being controlled at 1150 C.-1200 C.;

(6) (1c) heating the tube body to 950 C.-1000 C.;

(7) (1d) oil cooling the tube body; and

(8) (1f) tempering the tube body, with the tempering temperature being 600 C.-650 C., so as to achieve a mechanical feature of 110 ksi at the tube body and the thickened ends;

(9) (2) manufacturing a superior 13Cr internally threaded coupler and a superior 13Cr externally threaded coupler, respectively, with the composition formulations thereof being controlled to be the same as that of the tube body:

(10) (2a) obtaining a blank;

(11) (2b) forging the blank at 1150 C.-1200 C.;

(12) (2c) heating the forged blank to 600 C.-700 C. for a stress-relief annealing;

(13) (2d) rough machining the blank;

(14) (2e) after heating the rough machined blank to 950 C.-1000 C., quenching and cooling same in an oil tank; and

(15) (2f) tempering, with the tempering temperature being controlled at 600 C.-650 C.;

(16) (3) connecting the superior 13Cr internally threaded coupler and the superior 13Cr externally threaded coupler respectively to the two ends of the superior 13Cr tube body by means of frictional butt welding;

(17) (4) after heating seam areas to 950 C.-1000 C., cooling same to below 200 C. by ejecting compressed air onto the surfaces of the seam areas, and then cooling the seam areas to room temperature by spraying water; and

(18) (5) tempering the seam areas by heating to 640 C.-700 C.

(19) The composition formulations of the tube bodies and couplers in embodiments 1-5 of the present application are shown in table 1.

(20) TABLE-US-00001 TABLE 1 (wt %, with a balance of Fe and other inevitable impurities) Type of Steel C Si Mn Cr Mo Ni Embodiment 1 0.04 0.24 0.35 12.2 1.9 5.8 Embodiment 2 0.03 0.32 0.52 12.9 2.8 4.1 Embodiment 3 0.02 0.36 0.95 13.8 1.2 5.2 Embodiment 4 0.03 0.42 0.82 13.5 2.1 4.3 Embodiment 5 0.04 0.28 0.45 12.5 1.3 5.5

(21) Process parameters in embodiments 1-5 of the present application are listed in table 2.

(22) TABLE-US-00002 TABLE 2 Temperature Tube Tube Seam for body body Coupler Coupler Seam air Seam thickening quenching tempering annealing quenching quenching cooling tempering Type of tube temperature, temperature, temperature, temperature, temperature, temperature, temperature, Steel ends, C. C. C. C. C. C. C. C. Embodiment 1 1160 980 640 680 960 980 190 650 Embodiment 2 1180 970 630 650 970 970 105 670 Embodiment 3 1170 960 620 620 980 960 135 700 Embodiment 4 1185 990 610 660 975 975 155 660 Embodiment 5 1190 975 625 640 990 990 180 640

(23) Properties of the respective tube body and seams in embodiments 1-5 of the present application are shown in table 3.

(24) TABLE-US-00003 TABLE 3 Tube body Tube body Seam Seam yield tensile yield tensile strength, strength, strength, strength, Type of Steel MPa MPa MPa MPa Embodiment 1 830 955 867 958 Embodiment 2 870 980 832 920 Embodiment 3 925 990 775 871 Embodiment 4 955 1050 851 935 Embodiment 5 910 990 883 965

(25) It can be seen from table 2 and table 3 that the tube body of the superior 13Cr friction-welded drillrod manufactured by the method according to the present technical solution can achieve a mechanic feature of 110 ksi, and the seams can also achieve a mechanic feature of 110 ksi.

(26) It should be noted that what are set forth above are only particular embodiments of the present invention, and that clearly the present invention is not to be limited to these embodiments, but covers many similar variations thereof. All of the variations either directly derived from or associated with the disclosure of the present invention by those skilled in the art will fall into the protective scope of the present invention.