RU2287389C1 - Mill for assembling and welding straight-seam tubes of two semi-cylinders - Google Patents

Abstract

FIELD: welded tube production, namely mill for assembling and welding straight-seam tubes of two semi-cylinders.

SUBSTANCE: mill includes mounted along the same line: stand for fixing mandrel; inlet stand' drawing stands; welding stand; backup rollers; guiding cutters and inner mandrel. Each drawing stand includes drive vertical rolls whose upper and lower chocks are mutually joined through cross piece in which screw-down mechanisms are mounted. Screw-down mechanisms are built in mounted on housing mechanisms for moving rolls in horizontal plane. Inner mandrel is provided with spring-loaded lower backup rollers and vertical rolls mounted in grooves of said mandrel. Vertical rolls are provided with bearing units mounted in shafts of rolls at both sides and having guides for placing spring type compensating members. In bearing unit of one roll said guides are fixed and in other roll said guides pass through openings of bearing units and they are fixed at outer side of bearing units by means of nuts setting stroke of spring type compensating member.

EFFECT: improved quality of welded seam, enhanced efficiency due to shortened time period for repairing damaged seam.

2 cl, 4 dwg

Description

The invention relates to the field of pipe welding production, in particular to the production of long-distance electric welded pipes of large diameter of finite length from two half-cylinders.

Known mill for the production of welded two-seam pipes, see.with. USSR No. 254452, cl. In 21 C 37/08, 1967, consisting of a chain feeder, a movable mechanism (pusher), a half-cylinder assembly mechanism, a feed stand and a welding unit. The pusher is equipped with a traverse with spring-loaded levers that feed the workpieces to the welding unit, and when the traverse returns, they pass the next workpiece. The assembly mechanism of the half-cylinders contains a cage made of rings pulled together by rods. The cage can be rotated on the rollers with a drive. The holder is fixed in a horizontal position by vertical rollers. Guide rollers are fixed on each ring, the axes of which are offset relative to each other. On the same rings idle rollers of live rolls are strengthened.

The disadvantage of this device design is the low accuracy of the assembly of semi-cylindrical workpieces due to their asymmetric arrangement, because the half-cylinders in the assembly device occupy an arbitrary position within the size of the free space between the edge guiding rollers and the roller conveyor rollers, which are installed with a view to possible fluctuation in the sizes of the semi-cylindrical workpieces, which leads to unequal values of the upsetting of the edges, and therefore to poor welding quality. In addition, the edges of the welded semi-cylindrical billets when they are ejected from the device undergo additional deformation resulting from passage through the feeding stands, since there is no device (mandrel) that fixes the movement of the upper roll of the feeding stands when creating the necessary pulling force (it is not the same for each size). Additional deformations acting on the welded edges adversely affect the quality of the weld, forming microcracks.

Of the known mills for the assembly and welding of longitudinal pipes, the closest in technical essence is the mill for the assembly and welding of longitudinal pipes, described in A.S. USSR No. 1156765, class B 21/37/08, 1982

This mill contains a stand mounted in one line for fixing the mandrel, an input stand, pulling stands, a welding stand, supporting rollers, guide knives and an inner mandrel. In the pulling stands, the pulling rolls are arranged horizontally, the upper roll is made of rubber. The inner mandrel is equipped with edge leveling, support and holding rollers. In the zone of the pulling stands on the inner mandrel installed rolls interacting with the rolls of the pulling stands. In this case, the upper mandrel rolls are made of rubber. The inner mandrel is pivotally mounted on the knife.

A disadvantage of the known design of the mill for the assembly and welding of longitudinal pipes is that the pulling stands are made with a horizontal arrangement of rolls, which are constantly in force contact with the edges of the welded pipe billet. The pulling force of the stand roll is determined by the formula F = K · P, where K is the coefficient of friction between the rolls of the stand of the tube stock and the rolls of the inner mandrel, P is the force acting on the rolls, K is the friction coefficient can change for the following reasons: due to surface wear rubber on the rolls, each tube size is characterized by its radius of curvature, which may not coincide with the radius on the rolls, so the contact area of the rolls and the tube stock is different; due to humidity in the workshop; due to the cleanliness of the surface of the roll barrel and tube billet, and so that the pulling force of the rolls is constant, it is necessary to apply more force to the rolls, which negatively affects the formation of the seam and leads to the formation of microcracks along the length of the seam, which reduces the quality of the pipes.

Another disadvantage of the known design is the rapid wear of the rubber of the rolls, because they are constantly in contact with the sharp edges of the end face of the workpiece. This leads to mill stops for replacing rubber rolls in stands and mandrels, resulting in reduced productivity. It is impossible to install steel rolls, since the friction coefficient decreases several times, which means that the force acting on the rolls will increase many times, which will lead to a gap along the length of the weld.

The objective of the present invention is to provide a mill for the assembly and welding of longitudinal pipes from two half cylinders, which allows to improve the quality of the weld by reducing the effect on the edges of the welded pipe billet of undesirable deformation from the force formed by the rolls of the pulling stand and the rolls of the mandrel.

The task is achieved by the fact that in the mill for the assembly and welding of longitudinal seam pipes from two half cylinders, containing a stand installed in one line for fixing the mandrel, an input stand, pulling stands, a welding stand, supporting rollers, guide knives and an inner mandrel, according to the invention, a pulling stand made with vertical drive rolls, the upper and lower pillows of which are interconnected by traverses with clamping screws fixed to them, built into the mechanisms mounted on the bed, providing horizontal movement of the rolls, the inner mandrel is equipped with spring-loaded lower support rolls, upper and lower support rollers and vertical rolls installed in the guide grooves provided on it, in addition, the vertical rolls are equipped with supports with guides on both axes on which spring compensators are located, moreover, in the bearings of one roll, the guides are fixed motionless, and in the other roll they pass through the holes made in the supports, and from the outside The supports are fixed with nuts that determine the travel of the spring compensator. In addition, the vertical rolls of the mandrel and the vertical rolls of the pulling stand are located in the same vertical plane against each other.

Such a constructive implementation of the mill for the assembly and welding of longitudinal pipes from two half-cylinders can improve the quality of the weld by reducing the effect on the edges of the welded pipe billet of undesirable deformation from the force formed by the rolls of the pulling stand and the rolls of the mandrel. This is achieved due to the vertical arrangement of the rolls of the pulling stands and the mandrel rolls, because the forces of action of the rolls of the pulling stand and the mandrel are closed on the solid metal of the workpiece, and not at the junction of the workpieces.

In addition, the productivity of the mill is increased by reducing the time it takes to repair a damaged joint.

To explain the invention, a specific embodiment of the invention is provided below with reference to the accompanying drawings, in which:

figure 1 - shows a General view of the mill for the assembly and welding of longitudinal pipes from two half cylinders, General view;

figure 2 is a view of figure 1;

figure 3 is a section bB in figure 1;

figure 4 - view In figure 1.

A mill for assembling and welding longitudinal pipes from two half-cylinders contains a stand 1 installed in one line for fixing the mandrel, an input stand 2, pulling stands 3, 4, a welding stand 5, supporting rollers 6, guide knives 7, 8 and an inner mandrel 9.

The input stand 2 is equipped with a housing 10 with roller cassettes 11 installed in it and mounted on racks 12, on which lifting mechanisms 13 are mounted, which are used for transshipment of the stand.

Each pulling stand 3, 4 is made with vertical drive rolls 14, the upper 15 and lower 16 pillows of which are connected by traverses 17 with the compression screws 18. The pressure screws 18 are integrated in the horizontal movement mechanisms 20 of the rolls mounted on the bed 19.

The pulling stands 3, 4 are installed on the plates 21, 22. In the plates 21, 22, lifting mechanisms 23 are mounted, which are used for transshipment of the pulling stands 3, 4 when switching to another pipe size.

In the welding stand 5 with the welding machine 24, side roller cassettes 26, a central roller cassette 27 and the upper roller cassettes 28 are installed on the housing 25. The welding stand is mounted on racks 29. On racks 29 mounted lifting mechanisms 30, used for transshipment of the stand.

The inner mandrel 9 is equipped with spring-loaded lower support rolls 31, upper 32 and lower 33 support rollers and vertical rollers 34, 35 installed in the guide grooves 36 provided thereon. The mandrel 9 is pivotally mounted on a knife 7, which is mounted on stand 1 for fixing the mandrel. Knife 8 serves to maintain the angle of the cone of convergence of the edges of the workpiece before welding.

The vertical rolls 34, 35 are equipped with supports 38, 39 mounted on their axles 37 on both sides with guides 40, on which spring compensators 41 are located. In the supports 38 of the vertical roll 34, the guides 40 are fixed, and the vertical roll 35 passes through holes made in the supports 39, and on the outside of the supports 39 are fixed with nuts 42. The position of the nut 42 on the guide 40 determines the stroke of the spring compensator 41.

Vertical rolls 34, 35 of mandrel 9 and vertical rolls 14 of each pulling stand 3, 4 are located in the same vertical plane against each other.

The device operates as follows.

Before feeding the workpiece 43 to the mill, calibrate the gauges of the input stand 2, the pulling stands 3, 4, and the welding stand 5, corresponding to the pipe size. The knife 8 and the mandrel 9 installed in the mill are also adjusted to a given caliber. The pipe billet 43, oriented by the guide knife 7, is fed into the input stand 2, then into the pulling stand 3 and then into the welding stand 5, where the edges of the workpiece completely converge to a given welding gauge, and assembly and retention of the edges of the workpieces is carried out by the upper rollers 28 , side and central roller cassettes 26, 27 and support rollers 32, 33 of the mandrel. After that, the welding machine 25 is turned on and the workpiece 43 moves with the speed of welding by vertical pulling stands 3, 4 to the exit from the mill, during the welding process, the external forces on the welded edges from the rolls of the pulling stands and the mandrel rolls do not. When switching to the manufacture of pipes of a different standard size in the mill, the mandrel 9 is rolled out of the mill, then the input, pulling and welding stands are lowered or raised, the required number of measured pads are put in or put down, the stands are lowered and fixed, and the adjusted mandrel is rolled into the mill and fastened to the desired gauge on the knife.

The proposed mill for assembly and welding and welding of longitudinal pipes of their two half-cylinders in comparison with the known ones allows to improve the quality of the weld and increase productivity by reducing the time it takes to repair a damaged weld.

Claims (2)

1. Installation for assembly and welding of longitudinal pipes from two half-cylinders, comprising a stand installed in one line for fixing the mandrel, an input stand, pulling stands, a welding stand, supporting rollers, guide knives and an inner mandrel, characterized in that each pulling stand is made with vertical drive rolls, the upper and lower pillows of which are interconnected by traverses with clamping screws fixed in them, integrated into mechanisms mounted on the bed, which ensure the movement of the rolls in the horizon flax plane, the inner mandrel is equipped with spring-loaded lower support rolls, upper and lower support rollers and vertical rolls installed in the guide grooves provided on the mandrel, while the vertical rolls are made with supports mounted on their axles on both sides with guides on which spring compensators are located moreover, in the supports of one roll, the guides are fixed motionless, and in the other roll pass through the holes made in the supports, and from the outside of the supports are fixed with oschyu nuts, determining the course of the spring compensator. 2. Installation according to claim 1, characterized in that the vertical rolls of the mandrel and the vertical rolls of the pulling stand are located in the same vertical plane opposite each other.

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