MX2008000671A - System5 method, and apparatus for reducing residual stress in as-welded roller cone bit ball plug welds - Google Patents

Abstract

A roller cone bit has a ball retention system to secure the cones to the head. A radial ball race includes a ball way with a ball plug to keep the balls in the ball race. The ball plug is secured to the head by welding. Any residual stress in the weld region is alleviated by one of several solutions. Material may be selectively removed from the weld, the heat-affected zone, and/or the surrounding area to promote relaxation of residual stress. Alternatively, deflection is imposed and/or heat or vibration is applied to promote relaxation.

Description

SYSTEM, METHOD AND APPARATUS TO REDUCE RESIDUAL EFFORT IN WELDING BLOCKS FOR SWIVEL CONES BARRENA SOLDADA IN GRUTO Technical Field Field of the Invention: The present invention relates, in general terms, to the reduction of effort in rotating cone bits and, in particular, to an improved system, method and apparatus to reduce the residual stress in bituminous ball welds. of rotating cones welded in the rough.

BACKGROUND OF THE INVENTION State of the Art: Drills for rotary type drills include both rotary cone bits and friction bits. In a rotary cone configuration, the auger normally has three cones, each rotates independently with respect to the auger body that supports the cones through the bearing unit (bearing). The cones are provided either with integrated teeth or inserts formed separately that provide the cutting action to the auger. Normally, rotating cone bits use a bearing retention system to secure the cones to the heads. The retention system includes a radial bearing track incorporated in each cone and the head bearings. A rolling path between the head raceway and the OD of the head (OD) is provided to facilitate assembly. When the cone conforms to the head, the respective bearing tracks are aligned and, together, define a toroid or ring-shaped space. The rolling bearings are introduced by the bearing path into a space. A sealing ball is then inserted into the bearing path to block the discontinuity (ie the hole) in the head raceway and ensure that "the bearing bearings are retained within the track. The outer diameter of the head is welded in. While it is cooled after welding, residual stress can accumulate in the welded region (for example, the melting and heat-affected zones) Depending on the orientation and magnitude of the residual stress, it can be significantly reduce the payload or service capacity of the unit This structural configuration causes a type of failure in the head section, which includes cracks that start at the root of the sealing ball weld that propagate towards the diameter of the spindle and then return and propagate to the base of the bearing pin. Solutions are desired to deal with this problem .

Description of the Invention One embodiment of a system, method and apparatus of the present invention describes various solutions for reducing the residual stress in the region of the raw or recent seals of the sealing ball. In one embodiment, material is selectively removed from the weld, from the heat affected zone and / or the surrounding area to promote relaxation of residual stress. In an alternative embodiment, deflection is imposed and / or heat or vibration is applied to promote relaxation. By reducing the residual stress in the area of the weld by the present invention, the service load capacity and / or the service life is increased. These and other objects and advantages of the present invention are apparent to those skilled in the art, in view of the following detailed description of the present invention, considered together with the appended claims and the accompanying figures.

BRIEF DESCRIPTION OF THE FIGURES For the way in which the characteristics and advantages of the invention, as well as others, are evident and can be achieved and understood in greater detail, a more particular description of the invention summarized above can be obtained by reference to the modality of the same that is illustrated in the attached figures, whose figures form part of this specification. However, it should be noted that the figures illustrate only one embodiment of the invention and, therefore, should not be considered as limiting the scope of the invention since it can admit other equally effective modalities. Figure 1 is a cross-sectional view of a rotary cone auger embodiment constructed in accordance with the present invention; Figure 2 is an enlarged sectional view of a portion of the head and cone of a rotating cone auger of Figure 1 and constructed in accordance with the present invention; Figure 3 is an enlarged sectional view of another embodiment of a rotating cone auger constructed in accordance with the present invention; Figure 4 is a high-level flow diagram of one embodiment of a method constructed according to the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION Referring to Figures 1 and 2, there is shown an embodiment of a spinning cone bore 11 constructed in accordance with the present invention. The auger 11 comprises an auger body 13 having heads 15 (one shown) with cones 17. Each head 15 and cone 17 includes a retainer system having a bearing track 19 at an intersection between the head 15 and the cone. 17. A bearing path 21 extends from the bearing track 19 to an outer diameter (left sides of Figures 1 and 2) of the head 15. The outer diameter forms a portion of a perimeter area 23 of the head 15. Perimeter area 23 generally includes a region of the head 15 extending from the bearing path 21 radially outwardly and axially inward with respect to the bearing path 21. The respective bearing tracks 19A, 19B of the head 15 and the cone 17 are aligned to define a toroid or ring-shaped space. Bearings 25 are placed in the bearing track 19 to mechanically retain the cone 17 in the head 15. A seal ball 27 is located in the bearing path 21 to retain the bearings 25 in the bearing track 19. A barrier 29, such as a weld, is formed adjacent the outer diameter of the head 15 to secure the sealing ball 27 in the bearing path 21. The present invention also comprises means for the reduction of stress with which the residual stress on the barrier (for example, the welds) 29 and the perimeter area 23 of the head 15 adjacent to the external diameter can be reduced to increase the load carrying capacity of the head. Service and life of the rotating cone 11 auger. In one embodiment, the measure to reduce the stress comprises an internal weld 31 (Figure 2) that is formed with a first material adjacent to the sealing ball 27. The weld 29 is formed in the internal weld 31 from a second material having a greater strength than the first material. The first material may comprise several different materials, including nickel, nickel alloy, stainless steel and inconel. The second material may comprise steel or the like. In addition, an individual weld comprising one or more passes can be used as the barrier 29. These modalities can also use a single material, such as nickel, to form the welds. Moreover, all the welding can be formed from a single, softer material. In another embodiment of the present invention, the stress reducing means comprises a vacuum 39 (FIG. 3) in the barrier 29. The vacuum 39 may comprise a perforated orifice extending in the axial direction with respect to the bearing path 21. The present invention also comprises a system for reducing the residual stress in a rotating cone auger 11. One embodiment of the system comprises the elements described above, which include the retention system for securing the cones 17 to the heads 15. In the barrier 29 and the area 23 of the perimeter is located a reduction of residual stress to increase the load capacity of service and service life of the rotary cone auger 11. The residual stress reduction may comprise an internal weld 31 formed adjacent to the sealing ball 27 of a first material and the barrier 29 may comprise an external weld formed in the internal weld 31 from a second material having a greater strength than the first material. The residual stress reduction can also comprise a heat treatment that can be carried out on the whole rotary cone auger 11. As shown in Figure 3, the residual stress reduction can be located and limited to the barrier 29 and the perimeter area 23, such as by a small device 35 (e.g., a thermal source, an ultrasonic tool)., etc.) and a regulator 37 for applying, respectively, a heat treatment or an ultrasonic vibration treatment to the barrier 29 and the perimeter area 23. As described above, the reduction of residual stress can be achieved by removing material from the barrier 29, such as by forming an orifice 39 in the barrier 29 extending in the axial direction with respect to the bearing path 21. The present invention also comprises a method for reducing the residual stress in a rotating cone auger. As shown in Figure 4, one embodiment of the method begins as indicated in Step 41 and comprises providing heads to a rotating cone auger, cones (Step 43).; securing the cones to the bearing heads located on the bearing track at an intersection between each cone and each head, each bearing track has a rolling path that extends from the bearing track to a perimeter area of the head (Step Four. Five); install a sealing ball on each bearing path to retain the bearings in the bearing race (Step 47); forming a barrier in the perimeter area to retain the sealing ball in the bearing path (Step 49); reduce the residual stress on the barrier and the perimeter area to increase the service load capacity and service life of the rotating cone bit (Step 51); before finalizing as indicated in Step 53. The method may also comprise forming an internal weld of a first material adjacent to the sealing ball and forming an external weld in the internal weld from a second material having a higher strength than the first material. Step 51 may comprise applying a heat treatment, such as subjecting the sealing ball to elevated temperatures during the stress relief operation. In addition, this embodiment may comprise locating the heat treatment to a limited portion of the rotating cone auger that includes the barrier and the perimeter area or subjecting the entire rotating cone auger to the heat treatment. Step 51 may also comprise applying an ultrasonic vibration treatment to the barrier and the perimeter area or removing material from the barrier, such as by forming an orifice in the barrier extending in the axial direction with respect to the path of bearing. Although the invention has been shown and described only in some of its forms, it should be apparent to those skilled in the art that it is not limited, but is susceptible to various changes without departing from the scope of the invention.

Claims (23)

1. CLAIMS 1. A method for reducing the residual stress in a rotating cone auger, characterized in that the method comprises: (a) providing a rotating cone auger with heads and cones; (b) securing the cones to the heads with bearings located on the bearing track at an intersection between each head and cone, each bearing track has a bearing path extending from the bearing track to a perimeter area of the head; (c) install a sealing ball on each bearing path to retain the bearings in the bearing race; (d) forming a barrier in the perimeter area for retaining the sealing ball in the bearing path by forming an internal weld of a first material adjacent to the sealing ball and forming an external weld in the internal weld from a second material that has a greater strength than the first material.
2. 2. A method according to claim 1, characterized in that the first material is selected from the group comprising nickel, nickel alloy, stainless steel and inconel and the second material is steel.
3. 3. A method according to claim 1, characterized in that it also comprises applying a thermal treatment to the barrier.
4. 4. A method according to claim 3, characterized in that it further comprises subjecting the sealing ball to elevated temperatures.
5. 5. A method according to claim 3, characterized in that it further comprises locating the heat treatment to a limited portion of the rotating cone auger that includes the barrier and the perimeter area.
6. 6. A method according to claim 3, characterized in that it further comprises subjecting the entire rotating cone auger to a thermal treatment.
7. 7. A method according to claim 1, characterized in that it also comprises applying an ultrasonic vibration treatment to the barrier and the perimeter area.
8. 8. A method according to claim 1, characterized in that it also comprises removing material from the barrier.
9. 9. A method according to claim 8, characterized in that it further comprises forming a hole in the barrier extending in the axial direction with respect to the bearing path.
10. 10. A method according to claim 1, further comprising forming an internal weld with at least one pass of a single material.
11. 11. A system for reducing the residual stress in a rotary cone auger, characterized in that it comprises: a auger body having heads with cones; a retention system to secure the cones to the heads, which includes a bearing track at an intersection between each cone and head, a bearing path extending from the bearing track to a perimeter area of the head, bearings in the head bearing track to mechanically retain the cone in the head, a sealing ball located in the bearing path to retain the bearings in the bearing race and a barrier that forms in the perimeter area to secure the ball in the path of tread; a heat treatment that is located and limited to the barrier and the perimeter area.
12. 12. A system according to claim 11, characterized in that the barrier comprises an internal weld formed adjacent to the sealing ball by a first material and an external weld formed in the internal weld of a second material having a greater strength than the first material.
13. 13. A system according to claim 12, characterized in that the first material is selected from the group comprising nickel, nickel alloy, stainless steel and inconel and the second material is steel.
14. 14. A system according to claim 11, characterized in that the sealing ball is subjected to high temperatures during the heat treatment.
15. 15. A system according to claim 11, characterized in that it also comprises a treatment of ultrasonic vibration of the barrier and perimeter area.
16. 16. A system according to claim 11, characterized in that it comprises a vacuum in the barrier.
17. 17. A system according to claim 16, characterized in that the vacuum comprises a hole in the barrier extending in the axial direction with respect to the bearing path.
18. 18. A system according to claim 11, characterized in that the barrier is a single weld formed from a material selected from the group comprising nickel, nickel alloy, stainless steel and inconel.
19. 19. A system according to claim 18, characterized in that the single weld is formed by at least one pass of a single material.
20. 20. A rotating cone auger, characterized in that it comprises: a auger body having conical heads, each head and cone includes a bearing track at an intersection between the head and the cone, a bearing path extending from the bearing track to an external diameter of the head, the respective bearing tracks of the head and cone are aligned to define a toroid or ring-shaped space, the bearings are located in the bearing race to mechanically retain the cone in the head, locates a sealing ball in the bearing path to retain the bearings in the bearing race and a weld is formed adjacent to the outer diameter of the head to secure the sealing ball in the bearing path; a vacuum formed in the welding.
21. 21. A rotating cone auger according to claim 20, characterized in that it further comprises an internal weld formed by a first material adjacent to the sealing ball and the weld is formed in the internal weld from a second material having a greater resistance than the first material.
22. 22. A rotary cone auger according to claim 21, characterized in that the first material is selected from the group comprising nickel, nickel alloy, stainless steel and inconel and the second material is steel.
23. 23. A rotating cone auger according to claim 21, characterized in that the vacuum is an orifice extending in the axial direction with respect to the bearing path.