Pre-precision Welded Spiral Welded Pipe Mill

Introduction

Pre-precision welded spiral welded pipe mill separates the forming and welding of steel pipes into two processes, and the forming machine shall be the model of high-speed forming. Different from the ordinary spiral welded pipe mill, complete welding is not carried out during forming, but only the joint of steel pipe is slightly welded by gas shielded welder, as long as the weld seam does not expand, then the steel pipe is cut off at a fixed length, and then transported to the fine welding mill for complete and fine welding of internal and external welds. The mode has many advantages: First, forming and welding are carried out separately, so that when fine welding is carried out, the influence from the forming process disappears and the weld quality is more guaranteed; Second, due to the adoption of high-speed forming mills (the speed can reach 8m/min), the production efficiency is equivalent to four ordinary mills, and the following fine welding mills are equipped with four mills, so that the comprehensive production capacity of one mill can reach 3-4 times that of ordinary mills. The mill is suitable for large steel pipe plants with good quality and high output. The mill is used to produce oil and natural gas (long-distance) transmission pipes, which have very high requirements on steel pipe materials and quality, and also have very high requirements on mill equipment and inspection equipment.

Model

Technology Flow

Raw steel coil → Coiling → Head disassembly → Centering → levelling → Centering → Shearing butt welding → Centering → Edge milling 1 → Edge milling 2 → Cleaning → Centering → Delivering → Bending guide plate → Forming → Pre-welding → Cutting → Steel pipe output → Clean THE welding slag spatter → Transport to fine welding line (four lines work at the same time) → Put on pipes → Align welding position → Weld inside and outside of steel pipe (welding seam tracking) → Take out pipes → Clean welding slag → Cut for sampling → Check and repair  → Grind steel pipe end → X-ray inspection → Pipe end expansion → Hydrostatic test → Ultrasonic continuous flaw detection → Flat head chamfering → Pipe end × light inspection → Finished product inspection → Weigh & measure length → Marking → Storage.