Production of large diameter welded pipes (1986)

Large-diameter pipes are transported by special transport.

Installation of pipes on a gas pipeline.

Transfer of installed pipes to a trench.

Panorama of an oil pipeline under construction.

Finished pipes in production.

Pipe plant workshop.

Forming a pipe blank.

Cartoon explaining the process of making a blank and types of pipes.

Installing a sheet on a straight-seam pipe production line.

Nine-roll straightening mill, on which the sheet is straightened.

An edge-cutting machine, on which the sickle-shaped side edges of the sheet are eliminated and their strict parallelism is ensured.

In the last stand of the edge-cutting machine, cutters remove a chamfer for welding.

Forming of pipe blanks is carried out in three stages.

It begins with bending the edges on a four-stand edge-bending mill.

The second stage is preliminary forming.

It is carried out on a hydraulic press.

Under the action of the bending die, the sheet acquires a U-shape.

At the final stage, a press with a force of 20,000 tons is used.

A device that measures the force of the press.

The stamp of the final forming press imparts a cylindrical shape to the workpiece.

The gap between the edges of the workpiece should not exceed 20-40 mm.

The formed workpieces are fed to the welding mills.

Each welding mill has a drive for advancing the workpieces at the welding speed.

The side and vertical rolls of the mill provide the gap size necessary for welding and the accuracy of the edge passage under the welding machine.

When welding the outer seam, the welding machine feeds two electrodes into the welding zone.

Welding is carried out under a layer of melting flux.

Cartoon showing the welding process.

The first electrode along the path is given oscillatory movements across the seam axis.

Cartoon explaining the reason for this movement.

Cartoon showing the welding process.

Cartoon explaining the reason for using a caterpillar-type copper shoe.

The result is a high-quality weld.

The pipe with a welded outer seam is freed from the slag crust and flux residues and transported to the machine for welding the inner seam.

Control panel for welding machines.

When the pipe moves at the welding speed, the double-arc welding machine welds the remaining third of the wall and forms an inner seam.

Cartoon showing the welding process.

The hydraulic unit cleans the seams from the slag crust and flux residues.

The diameter of pipes with one seam does not exceed 1220 mm.

An increase in the diameter to 1620 mm is achieved in the production of pipes with two straight seams.

Sheets intended for the manufacture of pipes with two straight seams, after straightening, planing, edge bending and preliminary shaping, are sent for final shaping.

In the assembly unit, a pair of semi-cylinders is aligned along the length and combined along the side edges and fed for welding.

After welding the first external seam, the workpiece is turned on the tilter and goes to another similar welding machine for welding the second external seam.

Then the workpiece goes to the machine, where the internal seams are welded one by one.

The welding mode is the same as for pipes with one straight seam.

Straight-seam pipes are fed for finishing.

Plasma cutters cut the ends of pipes with craters that occur when the arc is excited and extinguished.

The final finishing of pipes includes the operation of chamfering.

The chamfers are removed with a single-cutter semiautomatic machine.

This operation is necessary for subsequent welding of individual pipes together at the site of the oil pipeline.

Pipe calibration is carried out mechanically or on hydraulic expander presses.

Cartoon showing the operation of expander presses.

At the same time, the pipe is tested for strength and weld density.

Cartoon showing the process of manufacturing spiral-seam pipes.

The rolled strip is fed to the pipe welding unit, which consists of a number of machines and mechanisms connected in one technological process.

After the uncoiler, the strip enters the rolls of the straightening mill, from which it is fed to guillotine shears that cut the end of the strip to align it.

The strip then goes to a mobile butt welding machine, where its front end is joined and welded to the rear end of the strip already in the mill.

Once welding is complete, the machine returns to its original position, and the strip passes through a loop former.

Control panel for the pipe welding unit.

In the edge trimming unit, disk shears trim the side edges of the strip.

Chamfers for welding are removed with milling cutters.

Two important technological operations, forming and welding of a pipe blank, are combined in one unit.

Cartoon explaining the forming and welding processes.

The pipe coming out of the mill is cut into measured lengths with a plasma cutter, which is mounted on a self-propelled trolley.

After cutting is complete, the trolley with the cutter returns to its original position, and the pipe is sent for finishing.

Its operations are similar to the finishing of straight-seam pipes.

They are tested for maximum pressure on hydraulic pressure testing units.

All welded pipes are subjected to heat treatment.

Such treatment removes internal stress in the metal, improves the structure of the weld and the weld-affected zone, and increases the mechanical properties of the pipes.

X-ray units with television screens perform continuous quality control of welded joints.

Paint markers mark any defects that are detected, which are then corrected.

After careful inspection, the pipes are weighed, marked, and sent to the warehouse.

Alternating frames with panoramas of large-diameter welded pipe production workshops.