Construction preparation before installation of cold-drawn steel pipe? Pipeline trench should be excavated in accordance with the requirements of the drawings, the bricklaying of pipeline wells has been completed, the various types of cold-drawn steel pipes needed have arrived, the quality is intact, and the inspection is qualified. The required construction tools, including welding machines, cutting machines, hammers, polishers and so on, are well prepared. Only a series of preparatory work can start installation.
II. Installation Process of Cold Drawn Steel Pipe
Pipeline positioning is carried out according to the design of the drawings. Pipeline brackets are prefabricated according to the site conditions. Then the blanking is carried out according to the design and the site. Then the groove is ground by a polisher and welded. When welding, the strip is fed into the welded pipe unit. After rolling by multi-rollers, the strip is gradually rolled up to form a circular billet with an opening gap. The reduction of the extrusion roll is adjusted so that the weld gap is controlled at 1-3 mm and the weld ends are even. If the gap is too large, the proximity effect will be reduced, the eddy current heat is insufficient, and the weld crystals will not fuse or crack indirectly. If the gap is too small, the proximity effect will increase, the welding heat will be too large, which will cause the welding seam burning; or the deep pit will be formed after the welding seam is extruded and rolled, which will affect the surface quality of the welding seam.
Inspection of Installation Quality of Cold Drawn Steel Pipe
1. No bracket shall be welded at the weld seam, and no weld shall be found at the bend.
2. The deviation of vertical installation riser per meter should be less than 3 mm, and that of horizontal installation should be less than 1 mm.
3. The surface quality of straight seam welded pipe should be smooth, and no defects such as folding, cracking, delamination and lap welding should be allowed. The slight defects such as scratches, scratches, weld dislocation, burns and scars on the surface of straight seam pipes shall not exceed the negative deviation of wall thickness.