Key points and main equipment for processing large diameter straight seam steel pipes

Large diameter straight seam steel pipe process flow and main equipment

Process the two plate edges into the required form at one time. Steel plate edge milling machine: Mechanical processing of both sides of the plate used for pipe making, and making the parallelism of the two plate edges within the specified tolerance range, to manufacture high-precision Prepare the steel pipe.

Make the edge of the steel plate have the same curvature radius as the radius of the formed steel pipe. Steel plate pre-bending machine: The edge of the steel plate is pre-bent by processing the edge of the steel plate with welding grooves on both sides by the edge milling machine. Prevent excessively long straight edges from forming the steel pipe formed by the forming machine and ensure the roundness of the steel plate.

Fully automatic steel pipe forming machine: completes the bending and forming of various metal sheets.

Carry out further jointing and pre-welding. Steel pipe pre-welding machine: Form the qualified open tube blank by the forming machine to prepare for internal and external welding.

The welding trolley transports the workpieces along the track. The double-wire internal welding machine is used for automatic submerged arc welding of large-diameter straight seam steel pipes and cooperates with the host machine to achieve welding of the workpieces.

The welding trolley transports the workpieces along the track. Double wire external welding machine: used for automatic submerged arc welding of straight seam steel pipes, and cooperates with the host machine to achieve welding of the workpieces.

To change the roundness of the steel pipe, the steel pipe finishing machine: applies strong pressure from the outside section by section to the long round pipe with poor roundness, so that it can meet the relevant specifications and usage requirements.

Gantry mobile sensory straightening machine: used for straightening steel cylindrical pipes.

Straight seam steel pipe flat head chamfering machine: chamfer the end of the straight seam steel pipe according to the specified blunt edge and bevel angle.

Improve the dimensional accuracy of steel pipes. Steel pipe expander: stress relief.

Check whether there are penetration defects in the steel pipe under the specified pressure. 3000T hydraulic testing machine: conduct hydraulic testing on the welded pipe. Eliminate welding stress and forming stress to ensure the performance of steel pipes.

It can detect longitudinal and transverse defects and heat-affected zone delamination defects. Line wave testing equipment: 100% line wave non-destructive testing of all welds.

With the continuous improvement of rural environmental protection requirements and the development of my country's petroleum and gas industry. In particular, the layout of the energy pipeline network has led to an increasing demand for straight seam submerged arc-welded steel pipes, and there is an increasing demand for the localization of large-diameter straight seam steel pipes. The West-East Gas Transmission Project is a national standard project and requires 1.82 million tons of large-diameter straight seam steel pipes, of which 820,000 tons are large-diameter straight seam submerged arc welded steel pipes. Only part of them are domestic steel pipes.

Key points of large diameter straight seam steel pipe processing technology:

Rebar thread processing

① The thread shape, thread pitch, etc. of the large-diameter square tube used for processing steel threads must be consistent with the thread shape and pitch of the connecting sleeve and have been inspected by the matching gauges.

② When processing steel bar threads, water-soluble cutting lubricant should be used; when the temperature is lower than 0°C, 15%-20% large diameter square tube sodium nitrite should be added, and engine oil must not be used as lubricant or no lubricant sleeve should be added. Silk.

③The operator should check the appearance of the steel wire ends one by one and make operator marks.

④ For steel wire ends that have passed the self-inspection, 10% of the large-diameter square tubes of each specification should be randomly inspected, and no less than 10 pieces should be randomly inspected. If one of them is unqualified, all the processing batches will be inspected and unqualified wire ends will be inspected. It should be reprocessed and can be used after passing the inspection again.

⑤ The yarn heads that have passed the inspection should be protected with protective caps and sorted according to specifications for use.