LSAW steel pipe online heat treatment:
After the steel pipe welding, using two groups or more intermediate ring induction heating equipment to the whole pipe heating, which in a short period of time to often required temperature 900 ~ 920 ℃, and heat preservation time, air cooling below 400 ℃ after normal cooling, make whole tube organizations to improve.
LSAW steel pipe offline often in the furnace heat treatment:
Straight seam steel pipe overall heat treatment device have chamber furnace and roller hearth furnace, using nitrogen or hydrogen nitrogen mixture gas as protective atmosphere, to achieve no oxidation or light condition. As a result of the chamber furnace production efficiency is low, now often use roller hearth heat treatment furnace in succession.Whole heat treatment features are: in the process, the wall inside there is no difference in temperature, won't produce residual stress, heating and holding time can be adjusted, to adapt to the complex heat treatment specification, also can use the computer for automatic control, but the roller-hearth furnace equipment complex, high cost of operation.
According to the production process, straight seam steel pipe can be divided into high frequency straight seam steel pipe and submerged arc welding straight seam steel pipe.Submerged arc welding and straight seam steel pipe according to the different forming methods is divided into UOE, RBE, JCOE steel pipes, etc.Which according to the purpose is different, and different production working procedure, after. (can be roughly divided into the scaffold tube, fluid pipe, wire casing, stent tube, guardrail tube etc) under the wing of bohai xiang straight seam steel pipe manufacturer to introduce one of the most common high frequency straight seam submerged arc weld steel pipe and straight seam steel pipe forming process and production process:
1. The plate used in the manufacture of large diameter submerged-arc welding straight seam steel pipe, steel plate into the production line after the first full plate ultrasonic inspection;
2. The edge milling: through the two edges of the steel plate edge milling machine double-sided milling, make it meet the requirements of plate, plate edge parallelism and groove shape;
3. The bending edge: the use of bending machine for plate bending, make the edge of curvature;
4. Molding: on the JCO forming machine bending of the plate after half after many step punching, pressure into a "J" shape, and the other half of the steel plate bending, same pressure into a "C" shape, eventually forming the opening "O" shape
5. Early welding: the forming of straight seam welded steel pipe joint with gas protection welding and continuous welding (MAG);
6. The welding: the columns more wire submerged arc welding wire (up to 4) in the straight seam welded steel pipe inside;
7. The welding: adopting many wire submerged arc welding of columns in the side of straight seam submerged arc welding steel pipe welding;
8. Ultrasonic inspection Ⅰ: inside and outside of straight seam welded steel pipe weld and weld on both sides of the base of 100% of the check;
9. X-ray Ⅰ: 100% of inside and outside weld X-ray industrial TV inspection, using image processing system to ensure the sensitivity of detection;
10. Hole enlargement of submerged arc welding and straight seam steel pipe length hole diameter in order to improve the size precision of steel tube, and improve the distribution of stress in steel tube;
11. Hydraulic pressure test: steel pipe after hydrostatic testing machine for hole enlargement by root inspection to ensure the test pressure of steel tube meet the standard requirements, the machine has the function of automatic recording and storing;
12. Chamfering: after the inspection of steel pipe to pipe processing, meet the requirements of tube end groove size;
13. The ultrasonic inspection Ⅱ: root by ultrasonic inspection to check again after the straight seam welded steel pipe in the hole diameter, water pressure may produce defects;
14. X-ray Ⅱ: for hole enlargement and after water pressure test of tube X-ray industrial TV inspection and pipe weld shooting;
15. The pipe magnetic powder inspection: check on this to find out the pipe defect;
16. Corrosion protection and coating: qualified steel pipe according to user requirements for corrosion protection and coating.
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