Piling steel pipe is the steel pipe that made of steel or strip after crimping, specifications includes φ219-φ2232 different wall thickness, the implementation of SY/T5037-2000, GB/T9711.1-1997 standards and APISpec5L standards. It is widely used in natural gas, oil, chemical, power, heat, water supply and drainage, steam heating, hydropower station pressure pipe, thermal power, water and other long-distance pipeline and piling, bridges, steel and other engineering fields. The anti-corrosion method of punching steel pipe is also started by controlling one of the process. For example, add anticorrosion coating to outer surface of the pipe, which will increase the circuit resistance and decrease the corrosion current; coupled with DC power, so that the steel pipe causes negative potential to the soil and form the cathodic protection, which can eliminate the anode and cathode.
Piling steel pipe commonly adopts spiral welded pipe and LSAW steel pipe with large diameter. The surface of steel pipe weld seam shall not have cracks, arc breaking, crater, porosity and other defects. If there are above-mentioned defects existing, repairing welding is allowed, repairing welding is allowed. It is allowed to that there are steel strip butt weld on the steel pipe, and the steel pipe is allowed to be docked by two pipe sections. The welding can be carried out by submerged arc welding or manual welding. The main production process of piling steel pipe is mainly double-sided submerged arc welding technology. More detailes about submerged arc welding process and its pros and cons, please click the hyper-link to know.
Markings of piling steel pipe
Each of the accepted piling steel pipe should be marked with fadeless paint, and we should along the perimeter of the piling steel pipe brush 50mm wide white paint at about 200mm from the inside of the pipe end. The steel pipe used for the red pipe should mark red paint to show the difference:
1. Color should be eye-catching, and should ensure that the piling steel pipe exposed to the air at least 4 months does not fade;
2. Marking color should be from the end of 200mm, and brush the entire circumference, the letter height should be at least 25mm;
3. Using metric units;
4. The number of piling steel pipe should be compiled in sequence;
5. Piling steel pipe should have number;
6. doing die marking on the end of the pipe directly facing longitudinal weld seam.