DE2420150A1 - SEAM WELDING PROCESS FOR CONNECTING TWO PANELS - Google Patents

Description

Redpath Dorrnan Long Limited, Bedford, Bedfordshire - England

Seam welding process for joining two panels

When joining steel plates by welding, it is common to bevel the edges of the plates so that a small web-like surface remains at each edge, which are joined together, then the grooves thus formed with a Weld seam are provided.

The midsection of the joint where the two flat surfaces at the roof point of the joint come together, however, a weakened point is formed because there is no metallic connection between these flat webs. To this one To avoid lack of weld, it is common practice to chisel metal from the unwelded side until flawless Metal is reached and this is generally done by means of grooving tools. The chiseled area must then be machined by hand to compensate for small irregularities that could lead to a weakening of the weld seam and it the weld is then completed by filling the groove with weld metal.

The invention is based on the object of creating a welding method which takes the time to produce the weld seam

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Significantly shortened, in that the manual finishing is made superfluous, while at the same time the amount of in the ablation the abutting webs with removed weld metal is reduced.

According to the invention, this object is achieved by the method for joining two metal plates in that

a) at least one of the two edges to be connected is beveled in such a way that a narrow, flat one on that edge Bridge remains,

b) the two narrow web surfaces are butt joined together thereby forming a V-shaped groove on at least one side of the butted surfaces,

c) the V-shaped groove is provided with a weld seam and

d) metal from the other side of the abutting surfaces is removed until the abutting web surfaces are completely removed and the inner part of the weld metal is exposed.

Step (d) is carried out at least partially by relief grinding with a grinding wheel running at high speed, which exerts a substantially constant pressure on the metal to be removed and a substantially constant feed rate with the axis held in a direction perpendicular to the direction of the weld.

According to a preferred embodiment of the invention, both Sides of the edge beveled so that another V-groove is obtained on the other side of the butted surfaces is and in this embodiment is the revolving at high speed Grinding wheel profiled so that a tapered edge

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is obtained which encloses an angle which is considerably smaller than the angle of the other V-groove; according to a further Embodiment of the invention are both sides of both edges beveled so that V-grooves have been created on both sides of the butted surfaces and in this embodiment the high-speed grinding wheel is shaped to obtain a tapered edge, wherein the included angle is considerably smaller than the angle of the V-groove.

The grinding wheel preferably consists of a synthetic resin bonded wheel that automatically moves at a feed rate grinds from 3.16 m / min, but grinding speeds down to 2.67 m / min can also be used.

The angle enclosed by the edge of the grinding wheel is approximately 60 ° with a root radius of approximately 76 mm. However, the angle can vary between 40 ° and 70 °. Such a dimensioning is particularly suitable for a connection in which the grooves encompass 90 ° on one side and 60 ° on the other side, the metal being removed on the 90 ° side.

The method is particularly suitable for the production of grooves, in cylindrical steel workpieces, especially in steel cylinders, which are used to make tubular legs for oil rigs create.

To create the circumferential weld seams between adjacent cylinders that form the tubular legs First the inside hem is beveled and then welded, and then the metal is outside by grinding with a high-speed Grinding wheel worn away.

The high-priced grinding wheel is preferably on one with Counterbalanced arm mounted and arranged so that the

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The grinding edge of the disc faces up. The arm is preferred controlled by a pneumatic cylinder to allow the operator to easily apply pressure to the grinding wheel control in the grooves.

The invention can also be used for longitudinal seams. Preferably the pipe is rotatably supported with its axis horizontal and the inner seam is near the bottom dead center welded and then the pipe is rotated and ground near top dead center.

Preferably the grinding wheel is carried by the end of a beam, which in turn is supported by a vertical column.

In all embodiments of the invention, a further Welding can be made on the inner portion.

To avoid removing large amounts of material by grinding the initial material removal can advantageously be carried out by known methods, e.g. by electric arc, Cutting or flame cutting can be removed. After this process, the grinding process according to the invention can be carried out to straighten small imperfections. In the following description, however, reference is made to only one Metal removal by grinding.

The invention also includes the workpiece welded according to the invention.

Exemplary embodiments of the invention are described below with reference to the drawing. In the drawing show:

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Figure 1 to 6 the production of a longitudinal seam according to the invention;

FIG. 7 is a perspective view of a grinding wheel carried by the swivel arm of a carriage for grinding all-round welds;

FIG. 8 is a view of another carrier for a grinding wheel with a pneumatic cylinder control system;

FIG. 9 is a schematic view of an all-round Weld in section along the line IX-IX according to FIG. 8;

Figure IO a view of a column support arrangement for a Grinding wheel for making weld seams running in the longitudinal direction according to FIG. 1 until 6;

Figure 11 is a schematic view of other connections according to the invention.

In the manufacture of cans or pipes that must be joined together to make legs for oil production platforms the base material is a steel plate with a thickness of approximately 15 * 9 ram to 70 mm. The plate 10 shown in Figure 1 is beveled at its ends - as shown - with a narrow, flat surface 11 of about 5.2 mm remains at each end. The plate is then bent around a circular shape and it becomes the flat surfaces brought together, as shown in FIG. The angle enclosed by the inner groove 12 is approximately 6O °, while the angle enclosed by the outer groove 13 is approximately 90 °. The inner groove 12 is then welded to successive layers 14 of weld metal. The contiguous flat surfaces 11 are in non-welded contact

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and because of the lack of a metallic connection at this point, a weakening would occur. According to the invention this metal surface is now removed by an automatic grinding wheel rotating at high speed 15 - like can be seen from Figure 4 - is applied.

The grinding wheel 15 has an edge 15 a, which is on a 60 ° enclosing angle is ground and the tip 15b is formed with a radius of 4.8 mm. The grinding wheel consists of plastic-bonded material and cuts at a feed speed of around 317 m / min. She is used to remove so much metal that the inner weld metal comes to light. The cross-sectional area of the metal removed is denoted by 16 in FIG.

Then the weld - as can be seen in Figure 6 - is completed, by successively applying layers of weld metal 13a, covering the space 16 and the remainder of the groove 13 to complete.

A grinding machine is described below with reference to FIG. ne described, which enables the implementation of all-round weld seams. The grinding wheel 15 is supported by a pivot arm 16a carried, which is balanced by the weight of an electric motor 17. The arm 16a is carried by a linear bearing that lies between blocks 18 which are attached to upright frames 19 of a carriage 20. The arm 16a is with two handles 21, which enable the operator to press the grinding wheel against the welded groove in the workpiece. The linear bearing enables the arm 16a to float to the side between the frames 19.

The grinding is carried out by a modification of the embodiment according to FIG. 8, the pivot arm 16a again being supported by bearings l8a is carried, which by means of a pivot bearing in the frame

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19 of the carriage 20 are attached.

The movement of the arm 16a is effected by a pneumatic piston-cylinder arrangement 22 controlled. The cylinder is articulated at 23 on the frame 24 and the piston is articulated on the arm 16a at 25. the The piston-cylinder arrangement is controlled by a lever 26 which is attached to a handle 21. The lever 26 controls a valve 27, which is connected to the cylinder 22 via flexible hoses 28 and 29. The cylinder 22 is filled with compressed air fed via a line 30. There is also a hydraulic telescopic damper 31 pivotable on the arm 16a and on the frame of the carriage 20 hinged.

The operator can then determine the position of the grinding wheel 15 relative to the workpiece by actuating the valve 27, whereby the damper violates the grinding wheel 15 against the workpiece. When using this arrangement, the operator is no longer on his own physical Force required to hold the grinding wheel in place, as the device consists of the pneumatic piston and cylinder exerts a constant force controllable by the operator and the axis of the grinding wheel is mechanically perpendicular in a direction is held to the direction of the weld.

The tubular sections to be connected are rotated at a constant speed so that the feed speed of the partially formed weld remains exactly constant compared to the grinding wheel.

When applying the invention to the welding of longitudinal seams the machine according to FIG. 10 can be used. Figure 10 shows one end of a beam 33, the usual, not shown Way is supported by a pillar. At the end of the beam 33 there is a boom 34 on which a curved arm 35 is pivotable is hinged.

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The arm 35 carries an electric motor 36 that controls the grinding wheel 37 drives, together with a housing 38 on an arm 39, which is pivotably articulated on the curved arm 35. The electric motor drives the grinding wheel via a chain drive.

The depth of the grinding wheel 33 is controlled by an adjusting device 40 which is arranged on a pivotably articulated L-shaped arm 41 which carries a depth control wheel 42 at one end. In addition, other conventional settings are used to control the inclination and position of the grinding wheel and to restore the grinding edge of the wheel to its desired profile shape. The grinding wheel 37 in turn consists of a synthetic resin-bonded wheel, normally about 16 inches in diameter. The grinding edge is provided with a 60 ° enclosing angle and the tip has a radius of curvature of 3j 76 cam *

When used for the production of longitudinal weld seams in pipes, the inner weld seam first had proven to be useful manufacture, working along the bottom edge of the inside of the cylinder, then around the tubular body 180 ° is rotated around its axis, so that the relief grinding and the external welding from the top manjbell line of the pipe can be done.

In the simplest embodiment of the invention, only one needs To be made bevel, which is indicated in Figure 11 with the reference numeral 51. The relief grinding can then done from the other non-beveled side of the panels to remove the flat butted surfaces, so that the weld metal on the back of the plates can fuse with the metal that was in the original V-groove has been deposited.

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The edge of the other plate can be beveled - as shown in dashed lines at 5k - and in this case the original groove can be made wider.

Instead, or in addition, one or both of the edges on the other side of the panel can be beveled, as at 55 and 56 shown in phantom. However, one embodiment is one edge of which is beveled on one plate at and the opposite edge of the other Plate is beveled at 56, not an appropriate combination to evaluate.

The use of an automatically controlled grinding wheel is appropriate Profile enables the operator to remove only that material during the grinding process, which otherwise a weakened zone results. This speeds up the manufacturing process and reduces the risk of weakened areas prevented.

Claims 409847/0830

Claims (12)

- Io - claims 1.) Method for connecting two metal plates along their butt-opposed edges, characterized
by combining the following levels: a) at least one of the edges to be connected is beveled so that a narrow flat Surface remains at each edge, b) the narrow flat web-shaped surface becomes with a corresponding flat web-shaped Surface of the adjacent edge of the other plate butted together so that a V-groove at least on one side of the butt against each other web-shaped surfaces is created, c) the V-groove is filled with a weld seam, d) metal is removed from the other side of the abutting surfaces until the abutting surfaces are completely removed so that the inner section is fully exposed to the weld metal, step d) being at least partially by relief grinding with a high-speed grinding wheel which exerts a substantially constant pressure on the metal to be removed and with a substantially constant feed rate being maintained and the axis of the grinding wheel being kept perpendicular to the direction of the weld seam. 409847/0830 2. Method according to claim 1, characterized in that the two edges to be connected beveled will. 3 »Method according to claim 1, characterized, that both sides of at least one edge are chamfered so that a V-shaped groove on the other side the butt against each other web surfaces is generated and that the expensive grinding wheel is profiled in this way is that a tapered edge is created which includes an angle which is considerably smaller is than the angle of the other V-groove. 4 * method according to claim 1, gekennzei characterized seframe that both sides of both edges are bevelled and V-Huten are formed on both sides of the abutting surface and that the hochturige grinding wheel profile lines so | _a is that a tapered edge is formed, which encloses an angle which is considerably smaller than the angle of the other V-groove » 5. Process according to claims 1 to 4, characterized in that that the relief grinding takes place with a grinding wheel bonded by synthetic resin, which is automatically with a Grinding speed of about 3.17 m / min works. 6. The method according to any one of claims 1 to 5 * characterized, that the one enclosed by the edge of the grinding wheel Angle is about 60 ° and the tip radius is about 4.76 mm, 409847/0830 7. The method according to claims 1 to 6, characterized in that is bevelled for welding röhrförmiger legs for a first olförderplattform the inseam and then welded and in that then the metal is removed from her outside with the high-speed grinding wheel. 8. The method according to claim I ₃
characterized in that the high-speed grinding wheel sits on a pivotably mounted arm equipped with a counterweight and is arranged so that the cutting edge of the grinding wheel faces upwards. 9. The method according to claim 8,
characterized in that the arm is moved by a pneumatic cylinder to enable the operator to precisely control the pressure of the grinding wheel in the groove. 10. The method according to claim 7,
characterized in that the tube is rotatably mounted with a horizontal axis and that the inner seam is produced while this seam is near the bottom dead center and that the tube is then rotated and the relief grinding is carried out near the top surface line. 11. The method according to claim 10,
characterized in that the grinding wheel is suspended from one end of a beam supported by a vertical column. 409847/0830 - 43 12. The method according to claims 1 to 11, characterized, that the removal of the metal at the weld seam is partly by chiseling or burning out and partly is effected by relief grinding. IJ. Method according to claims 1 to 12, characterized, that another weld is made on the inner exposed portion. 409847/0830