CN1008383B - Method for producing a tubular node - Google Patents

Abstract

The present invention relates to a method for producing a frame type structural tubular node composed of legs and jack posts of a steel pipe component using in offshore petroleum well drilling, movable platform production, etc. The legs of and the jack posts are mutually connected. In order to form the transition of the legs and the jack posts in the node, a rolled steel plate stock is used according to the method of the present invention; firstly, the rolled steel plate stock is bent into a shape corresponding to the curvature of the legs; then, the rolled steel plate stock is punched or extruded on a proper pressing tool to form the support legs of the jack posts extending outwards according to the required angle. The design of the support legs of the jack posts is used for welding auxiliary jack post pipes on a frame structure. Then, stock components with the support legs of the jack posts are welded to feet and form the wall parts of the legs in the node.

Description

Method for producing a tubular node

The present invention relates to the new solution that a kind of leg of being made by steel pipe and dagger are connected to each other the tubular joint structure that frame trussed construction together uses, this structure is used for the offshore oil drilling well and the activity in production of the fixing or mobile platform of big width.

The structure of such truss normally directly is welded on dagger on the leg and forms tubular joint, the just binding between leg and the dagger.This joint can be made up of a dagger and one leg, also can be formed by connecting on the face or on several by many daggers and leg.Though directly dagger being welded on leg from the viewpoint of structure is a kind of simple solution, should be noted that this solution can bring the infringement of a series of serious problems.At first need the surface to being welded to connect careful and high cost to carry out preliminary treatment and work in coordination, if dagger becomes the angle of inclination just to connect more trouble.Common connected thickness of pipe wall is different, and this makes welding more complicated.What come next is the control of welding quality, for example because be subjected to the restriction of accessibility, also very complicated with ultrasonic wave or this welding of X-ray examination.Experience shows, because above-mentioned former thereby often can not guarantee the quality of welding job.These problems become even more serious and outstanding under the situation that angled and many dagger joints are connected.

For rigidity and the intensity that strengthens joint often need increase the leg wall at joint place and the thickness of dagger wall partly, this measure further causes the difficulty of welding, and the weight of platform is increased and the cost raising.

Analyze from the angle of structural strength, existing solution commonly used is desirable not enough.This dagger/leg node is being represented discontinuity point geometrically, and this place can produce in material and rise to very high stress peak, also can cause stress to concentrate.The fact of tradition solution is that the place of being welded to connect just in time is those stress high concentration places, the intensity and the safety of this just inevitable further grievous injury joint.Because the environment wave is movable load forces character, the stress of recently common joint toe weld place height is concentrated and is made the fatigue strength problem particularly serious, can cause early stage cracked the making with the cracked development again in this place in commissure to be connected frequent failure.

Platform drilling cramp structure is badly damaged in the time in past, is especially resembling the North Sea in the adverse circumstances.Confirmed design, all must take into full account the structure of static(al) and fatigue strength, and will have enough safety factor resemble the offshore platform.This at first is that member must have enough intensity between dactylus and the joint, refers to that also this structure has enough little probability of failure.Form about destruction is as follows:

1. Jie static strength deficiency.Promptly, cave in because of often being subjected to overburden to produce overproof permanent deformation, or even fricting shearing fracture.

2. the rod member between the joint produces crooked or surrender.

3. owing to the tired extension that produces crack and crack.

In order between the leg of the work structuring of this class frame and dagger, to create higher with more durable being connected of a kind of intensity, must avoid in tubular joint welding, because this place has very high concentrated stress to produce, and should replace a kind of in prefabricated integral body joint composition dagger leg, so just can directly weld together with leg and strut as the part of structure.This solution is not also adopted by the industry of platform drilling cramp every-way so far, and is more not on probation in practice.Chief reason is that connection casting or die forging always exists the danger of inevitable die forging defective, such as internal porosity and crack, and the defective that this class may exist can not 100% absolute the assurance be checked out with known control appliance.The casting expense of foundry goods of saying this class shape further is very expensive, changes time-consuming a lot, and this casting usually must be away from carrying out in the factory that makes the drilling cramp position.

For the working frame to platform drilling cramp structure provides improved joint, some similar solution methods were proposed also.For example the patent No. is: other solutions that 140949,142454 and 145731 norwegian patent specification are mentioned.These patent disclosures integral part with relatively little diameter and product of the example of different types joint make with die forging or cast steel, strengthen with the welding gusset in some cases, or the like.The body portion of this joint is prefabricated into the short tube that needs shape, and the strut that is welded to the frame work structure then gets on.To further replenishing of this solution is to have used a kind of special tapering transition tube connector part between joint and large diameter tubular strut, and joint just can be made in the little overall dimension of regulation like this.From the undersized joint of the viewpoint of Static Design is desirable, can be assumed to a kind of feasible solution, but viewpoint from structure, on the one hand because the strength characteristics identical materials that to have used so-called scalar property's material be all directions (on the contrary, rolling sheet material is usually a little less than transverse strength), cause moment of flexure inertia to reduce because of size is little on the one hand, thereby reduced bending strength.

No matter how good in design with showing advantage aspect the static strength, the solution of this solid joint is not also adopted by the connection of machinery platform structure.When an one reason is the too high and manufacturing expenses of the cost of this joint, outside often build away from derrick in the place of making.Another important practical obstacle is the tube channel of having used this joint to make leg can not be used for the down lead of post or being used for drilling equipment, production equipment.

Another corral that further provides an annular about the solution suggestion of joint has one or several to be used for connecting the transition tube connector part that strut goes on the frame work in design on the ring around leg.Instantiation about this solution is to be connected the strut that respectively separates with a special ring with transition tube connector part on joint.This ring solution is in many aspects than above-mentioned solid knot cluster method more attractive, but this solution is gone out the problem that the joint of size itself can cause the mutual selection of problem that stress concentrates and trouble to cooperate to large-sized joint and stretching, extension, especially to the transition pipe fitting of ring.

Generally speaking, can conclude about the large-scale rahmen work structuring that is used for picture drilling platform platform well drilling structure purpose, described joint is the weak link that connects in this structure, this is to the overall strength of derrick or all be main threat concerning the life-span of derrick, because produce tired cracked meeting in the joint knot its is damaged.

Main purpose of the present invention be developed a kind of be used for the new improvement of large-scale steel framework work structuring the joint solution.

A further object of the present invention provide a kind of be used to connect with leg meet at right angles stretch or become or the manufacture method of the dagger joint that the skewed crossing angle stretches, for example become 45 angles of spending up or down with leg.

The purpose of method of the present invention provides a kind of tubular joint of frame construction of work truss, offshore drilling platform for example, the similar design of bearing surging condition, the member of being made up of the leg and the strut of steel pipe.

Characteristics of the present invention are that the composition of the transition tube connector between leg and the strut is to have utilized a kind of transition part of being made by rolling steel plate blank, the curve form that the formation of this blank elder generation can adapt and cooperate with the curvature of leg, impact with suitable compression tools again or extruding angle being used to of stretching welded the dagger leg that additional dagger pipe goes on the frame construction on demand to form one, after this dagger leg that should flat board forms is welded into of leg itself, thereby has formed an annular wall on joint.

According to the joint shape of structure and other standard, the tubular leg of formation can have an opening on vertical leg axis or plane at angle, for example becomes on the parallel plane with leg axis at one.

This include tubular leg part of the steel plate manufacture process can once finish in punching press and/or the extrusion operation respectively or repeating several times or unduplicated operation in finish, for recovering the extensibility of material, carry out intermediate heat-treatment.

The special tool(s) that is used on part of the steel plate making leg can be a circular cone columniform or that tapering is little, and more desirable end face is circular or the front end sphere.Mould has the opening of a complementation so that a transition region of suitably revising is arranged between the inner surface of inner plane and manufactured leg.

It is that it can be used for making the leg of inclination on the plate part that test provides the special benefit of this method.So can accomplish it is because of having used a kind of instrument that has piston or similar item like this, it be guided to leg on the consistent and described mould of direction of angle of the required one-tenth of part provide the opening that tilts to give correct, oval-shaped correction open area.

This plate part that includes leg can be formed the loop section of complete leg or only be the wall part of leg.The latter is unique selectable method when being connected with large diameter leg.This large diameter leg will be along forming (five steel plates partly weld together for instance) ring structure part on every side.This planar section can have with the other parts of leg and the identical thickness of joint part of leg as a kind of blank of doing leg, also can adopt thicker thickness, perhaps only one thickness that increases all be arranged at the planar section of joint or the planar annular part of the circumference of all legs.

By these solutions of the present invention, a kind of design of improved joint is provided, compared with the prior art more also have the other interests, especially strut is welded direct to the structure that leg gets on and compares more remarkable with common.Two parts that it can avoid linking together acutangulate, and the connection of acute angle will inevitably cause serious stress concentration.

This leg part from the thickness of leg neighbouring part to being attenuate equably with the thickness of the additional strut pipe of the opening welding of leg, so just can avoid pad just in time in the concentrated hazardous area of stress, the just annular intermediate zone between leg and strut.Adopt directly or from the extruding of leg material or stamp out leg, can obtain a kind of anisotropy leg product, promptly a kind of material, it is laterally big in the strength ratio that vertically has of leg.Show that technology of the present invention is having tangible progress than various forms of prior aries aspect stress and the distortion, this technology will extensive use on joint and leg.

The design of this joint must consider that just it stands fierce strut load and does not produce the ability of permanent deformation, fracture and the shear fracture of transition static strength.These must be checked with stretch-proof load and pressurization.The latter is under the condition that joint is not strengthened, because ovalisation is flattened and destructive mechanical breaking is more dangerous usually.The form that other destroys is the bending/surrender of the different piece of joint, the development of breaking at last and breaking and cause fatigue failure.

Calculating, practical experience and test have shown that the most dangerous mode of failure is fatigue failure, the platform that has surging wave environment especially for use in the sea advances the connection of shelf structure, for example in the North Sea, actual tests has shown that the present invention provides a kind of solution that is used for overcoming the problems referred to above.

Except above-mentioned reason, why the present invention can obtain good like this result's further reason.The pressure and the even tension ground that are danger that strut is suffered briefly in fact transmit and are assigned on the zone bigger on the leg, avoided the variation of unexpected accessory size simultaneously, between strut leg and leg, replaced or even the support of transition duct crooked or arch.

Further say, on the curve transition basis between leg and the leg part, need obtain placing the ultrasonic wave of the whole intermediate zone of inspection and the inlet of X-ray equipment, need transition region with reduced for what check simultaneously.

Say that further the inspection of necessity of planar section, the leg part of leg equally can carry out at manufacturing scene, so just needn't mobile checkout facility to the production scene of derrick.

Can also obtain entering the inlet of junction at last from both sides.The relevant spot welding strut that will seal on the leg surface connects something and also can not solve so far.

The present invention compares the advantage that has with the such joint of prior art and can be summarized as follows:

1. this joint can bear high fatigue loading.

2. this joint knot can obtain long working life.

3. that can avoid complex geometry and the welding job high tubular joint of cost.

4. the needs of the inspection of this joint operation have been reduced.

5. increase the possibility of designing the elongated and high derrick geometry that is used for deep water because joint of the present invention has big fatigue strength, and needn't use other requirement to be higher than the design standard (about 100 years waves of size) of static load.

The present invention has also comprised other important characteristic and progress, and these will embody in following manual.Here the present invention will illustrate with some relevant examples and signal accompanying drawing.

Fig. 1 a and 1b are the horizontal direction of the employed joint of drilling platform platform of the truss of being made up of tubular leg and strut that uses of extensive in recent years design or frame construction and the sectional view of vertical direction.

Fig. 2 has shown the flat board or the flat blank part of the leg that is used to provide the dagger leg, and the blank of this demonstration has one " starter hole ".

Fig. 3 a and 3b have shown the dagger leg that is used to make the band angle and used blank and the punching press or the compression tool of dagger leg at right angle.

Fig. 4 a has shown that instrument is piston and mould at extrusion operation with in the situation of the final position of the dagger leg of forming angle.

Fig. 4 b has shown that the dagger at right angle props up the molding structure at angle

Fig. 4 c shown Fig. 4 b amplification partial cross section.

Fig. 5 has shown the schematic diagram of the horizontal section of leg, and it provides the plate portion that has dagger leg of the present invention.

Fig. 6 a has shown the joint of strut leg and the horizontal schematic diagram of leg of having of the present invention.

Fig. 6 b-6e has shown and of the present inventionly has been used in the segmentation of the joint that has the dagger leg in different vertical facade parts.Fig. 6 b, c and d are the views before assembling, and Fig. 6 e is the joint that is assembled into.

Fig. 7 has shown a kind of akin joint that shows with Fig. 6 e of the present invention, but planar section there part can be selected arbitrarily.

Fig. 8 a-f has shown the joint of six kinds of forms of the present invention together.Joint commonly used as shown in Figure 1, it is made up of with the dagger leg 2 that has the edge of opening of correct radian or arch the ostiolate strut 4 of adjacency, and the radian of edge of opening is decided by the angle between dagger and the leg, and above-mentioned part is directly facing to the face of leg and contact with it.In the design of this class between mutually be welded to connect or fillet weld is confined to triangle or V-arrangement usually, weld seam is along outside mouth and closing line between leg and the strut.For inner welding also is provided, when beginning, leg to provide the dagger leg of a separation.(often being taper), it is welded on and also has inside weld on the leg, must check this weld seam then, use annular welds that dagger is welded on the dagger leg then, but it only has the welding 6 of outside.Therefore this design has just caused an extrahazardous zone, especially to having the angle strut, this hazardous area in Fig. 1 b with in the specified circle of sequence number 8.The working space that is used to weld in this zone is very limited, then the problem of checking with ultrasonic wave or X-ray equipment if possible, also will run into same difficulty, this point is very unfavorable, because will produce maximum stress or stress peak just in this zone.This " normal stress " peak value in joint is through 10 times to 30 of the paranormal stress of regular meeting.

Produce the danger of fatigue failure at the usual practice that welds of this zone of joint through the transition region of regular meeting between leg and strut, especially when bearing compressive stress repeatedly and more can causing destroying the result during tensile stress.The working life of this structure is very limited, especially uses the offshore platform drilling well, and the pulsating stress that it will stand the above-mentioned type that causes because of surging wave has shortened application life especially.

Fig. 3 a, 3b and 4a, 4b and 4c illustrate manufacturing and are used for the strut leg of the present invention's joint or the method for transition structure.As shown in Figure 2, the milled sheet of a ready bending or rolled plate 10, it provides a starter hole 12.Shown in Fig. 3 a or 3b, this slab spare is placed on one then and has mould 14a(and be used to dagger leg with angle) or 14b(be used for the dagger leg at right angle) punching press or compression tool in.The die face shape of this mould is corresponding to the curved surface of slab (not shown), and opening 16 oval or circle is provided simultaneously, and its size is corresponding with the size or the diameter of the dagger leg that will make.Opening on the mould or hole can reduce its radially outer size a little for helping making conforming to profile in some cases.When making a kind of dagger leg of the band angle shown in Fig. 3 a, the direction of the opening on this mould with an angle, the direction of the dagger leg made from desire is corresponding, this slab (not shown) that is positioned and fixed simultaneously, starter hole 12 is positioned in the minor face of the dagger leg shown in the deflection a little, therefore can realize deforming under the squeezing action of plate part and the last dagger leg that forms has circular and transverse end opening haply, further this product is evenly reducing towards its thickness of opening direction of end simultaneously.Keep homogeneous thickness haply on circumference, the thickness along sharp edge in the connection of the strut leg that has angle may be big a little.

Punching press shown in Fig. 3 a and 3b and Fig. 4 a or extrusion piston 20 have cylindrical shape, also can tapering be arranged slightly in outside direction, and its front end 22 is sphere form rather than the little taper of tapering preferably.This piston is supported with common pressure chuck or holder, make piston can be axially harness motion on the mould, this piston also should be able to carry out some transverse movements, because when making the dagger hole of band angle, starter hole is positioned in a slightly inclined to one side side at the tubular axis line, (this as Fig. 3 a as shown in) is so horizontal motion needs.For avoiding the initial rupture when the opening, this piston begins axially to be located immediately at the top of initial apertures, moves towards relevant central axis lentamente along with the expansion of opening then.

Fig. 4 c is the amplification of the partial sectional view in Fig. 4 b circle, illustrates the typical molding structure at the dagger leg 28 at the crimp 24 of 26 li of mould openings and a kind of right angle.

If desired, can known form in the opening of mould place a base or count tool with shown in the indicator diagram 4a apart from boundary line 22.

The operation of this punching press or extruding can be adopted various multi-form, and whether this will and carry out preheating to plate slab and decide according to the object of the product of making.

If carry out extrusion operation under situation about not heating, this extrusion operation must interrupt for several times, that is to say that extruding must carry out stage by stage.The number of times in stage will be decided (thickness that increases product with the diameter of dagger leg and dagger also increases usually) by the thickness of the diameter of dagger leg and product.Must heat-treat product between pressing steps, this product can thereby recover its extensibility and can further process by crystallization more like this.Must constantly control extrusion operation exactly, make it be no more than the yield point of product.

This punching press or extrusion process also can make into to process after the first preheating, for example are preheated to the scope of 800-1000% earlier.

This extrusion process can once be finished by relatively long lasting or long moving in some cases, or divides several steps to finish, and can upgrade heat treatment sometimes so that its Drawability of product to be processed recovery.

By above-mentioned punching press or extrusion process, can obtain a kind of dagger leg product that is called oriented structure, can obtain high-intensity material like this, can obtain the extensibility of the increase of the direction of extrusion simultaneously.If colding pressing of being referred to as or cold pressure processing, this slab will obtain in the rigidity near yield point, and the breakdown point of prefabricated dagger leg and hardness will be greater than through pretreated flat panel products.

Actual tests has proved that the dagger leg of this form manufacturing of employing has very high quality, and this pipe can have bigger diameter simultaneously, for example 1 to 2 meter, and the preferable thickness of while in scope 50-100 millimeter.

At the manufacture view of instrument, will there be suitable circular arc curvature at the edge of mould opening, and this point is extremely important, because this curvature will limit the bend radius of dagger leg in the hazardous area, and zone just from leg material itself to pipe itself.

Actual tests show tools design to such an extent that rationally can obtain optimal results, that is to say and to reduce the thickness of product on leg gradually, the wall thickness that maybe will form the transition portion of leg from the thickness of leg, arrive the wall thickness of the strut of adjacency, and strut is by thickness minimum (being generally the 20-50% of leg wall thickness).Actual tests has further shown can reach the requirement of reservation along the thickness on the leg wall limit of the buckled zone of danger, and the needs of this thickness of product are very important.The very easy understanding of this point promptly can avoid pad in the region of stress concentration or part of the danger of joint by the present invention fully.These external these zones can obtain uniformly in some cases than leg or the more strong material of strut itself.

Aspect the length of dagger leg, the leg that 45 is stretched will have one substantially to the corresponding size of dagger radius, in any case, always greater than a certain length, the hypotenuse of dagger leg can be parallel to the central axis of dagger or essence is parallel like this, so just can reach the snugly aligning that docks with strut, obtain circular preferably edge of opening.About the right angle leg, this length requirement is not strict especially, but the wall of leg to the youthful and the elderly to leg has sufficient stretching, extension, and parallel with central axis.Say in fact corresponding further with the product thickness of adjacent strut along the thickness of edge of opening to the youthful and the elderly to product.If need can with a wall thickness can be towards the outer end or being used for of reducing of the mouth conical transition section of welding dagger be welded on the leg.

Now talk stressing conditions about joint of the present invention.Can point out that fatigue strength, the durability by experimental measurement joint of the present invention is ten times of life-span of the welding joint commonly used of same-type and same size.

On this basis, the way of another change is to allow the same long life-span of welding joint that increases corresponding fatigue stress allowable and keep and use always accordingly.

In some actual conditions, when relating to the leg of band angle, when particularly angle surpasses 45 °, can prove that being difficult in outward direction on tube wall and the long limit is difficult to fully to obtain enough to product requirement, now just can obtain the change-over terminal opening on leg of needs, it has preserved the uniform product thickness that centers on the leg circumference with respect to the longitudinal axis of leg.For the uniform thickness of the edge of opening that keeps uniform product thickness, especially pipe, be crucial in a little things, leg is shortened or be very essential facing to the long limit inclination of leg wall.Otherwise it is not the plane of transversal position that the mouth of this leg will be positioned at a longitudinal axis with respect to pipe, the opening of leg will ovalisation like this, this shape needs to be welded to that oval-shaped opening cooperates with it on the strut of the adjacency that the dagger leg gets on, and made the complicated operation that connects joint and dagger some.

As previously mentioned, Fig. 6 a has shown a schematic cross-sectional view by joint of the present invention.

Fig. 6 b, c and d have shown that joint of the present invention is divided into three parts before assembling.Fig. 6 e has shown the b at Fig. 6, c, and the situation of the part shown in the d after assembling includes three dagger legs together, and each is positioned at the vertical position, space that separates of leg.The shank branch of this joint is design like this, and therefore the central axis of all dagger legs obtains firmly and design stably on the vertical central axis of leg.

Fig. 7 has shown this joint of forming with the identical joint structure that Fig. 6 shows, and unqualified arbitrary specific strapping wires on the leg structure have illustrated that this plate part that has comprised the dagger leg can be selected arbitrarily according to special needs.

The above-mentioned narration and the example of demonstration only are for method of the present invention is described.Scope of the present invention is only limited by appended claim.

Claims (6)

1, a kind of manufacture method that is used to connect the tubulose joint of leg in the truss and dagger steel pipe fitting, it is characterized in that with leg in the rolled steel slab composition joint and the transition between the dagger, this base is made and the corresponding curved shape of the curvature of leg, again with suitable compression tools with the method for punching press or extruding to form the dagger leg of the outside stretching, extension of angle on demand, described dagger leg is designed to additional dagger pipe is welded on the framework, therefore after this described base that has the dagger leg is welded into leg itself, has formed its wall part in the joint knot.

2, the manufacture method of tubulose joint as claimed in claim 1, it is characterized in that described dagger leg stretches obliquely with respect to the axis of pin, with punching press or extrusion form remove pin edge of opening in a plane with respect to dagger leg vertical axis tilt, be parallel to the axis of leg simultaneously in fact.

3, the manufacture method of tubulose as claimed in claim 1 joint is characterized in that squeezing out two or several dagger leg on one and same compact spare.

4, the manufacture method of tubulose as claimed in claim 1 joint is characterized in that the selection thickness of this dagger leg from the thickness of adjacency pin wall to the end openings place is attenuate equably, and this dagger leg has uniform wall thickness along the edge of opening circumference simultaneously.

5, tubulose as claimed in claim 1 restraining making method is characterized in that the first step provides an extruding starter hole on the described base, and this starter hole is on the axle by the dagger leg that is formed.

6, tubulose restraining making method as claimed in claim 1, it is characterized in that described base has stood punching press step by step or extrusion process to form the dagger leg on base, and gapped property time interval ground processes, in blanking time, base is heat-treated, make the product of base system before following road pressing steps, can recover its extensibility like this.

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