If the spiral pipe in the production process is unreasonable, the machine parameters set inappropriate deviation phenomenon will occur, especially large-diameter spiral pipe, which is often the wrong side of the phenomenon. For the production has been wrong side of the spiral pipe treatment program is as follows: 1, The location of the wrong edge polished, and then make up welding. 2, If the wrong side of the situation often occur, you can only replace the equipment. Spiral pipe produced after the wrong edge of the analysis of the reason is very necessary, the following is a common cause of wrong edge: 1, The sickle bend steel strip is the most important factor in the wrong side of the pipe. In the spiral pipe molding, the sickle bend steel strip will continue to change the forming angle, resulting in weld gap changes, resulting in open seam, the wrong edge or even take the edge. 2, The head and tail of the steel butt welding weld residual height larger, over-molded if handled properly, likely to cause greater wrong edge. 3, Due to the shape of the non-trimming steel head and tail and the size of poor accuracy, easy to cause when the steel strip bending caused by the wrong side. 4, The edge of the strip poor condition is another important reason for the wrong side. Therefore, it is an effective way to observe the sickle bend after uncoiling the steel strip, cut off the part of the scissors by controlling the vertical roller, and to continuously control and rectify the forming angle, so as to reduce the occurrence of wrong edges in the sickle bend of the steel strip during the production process.

1, Radial seal after the hydrostatic test. 2, Ultrasonic testing, to ensure that no internal vulnerability. 3, The welding parts of the mechanical properties, chemical composition, integration of the situation. 4, The vertical inspection of the end of the steel pipe and slightly modified the broken and blunt edges.

Longitudinal welded pipe fracture:  It has been found that when the temperature is below a certain temperature, it is found that the data will be converted to a brittle state, and its impact absorption is significantly reduced. This phenomenon is called cold and brittle, high-strength metal of the low stress brittle fracture process, the data organization is far from uniform isotropic organization will have cracks, there will be inclusions, pores and other defects, these defects can be seen as micro-cracks in the material. Therefore, the design should also be based on the work of the component temperature to select the appropriate cold brittle transition temperature of the information. In general, it is assumed that the information is uniform and continuous isotropic, according to this method analysis is considered safe design, and sometimes accidental fracture accident. As the hot-rolled tube billet cracks or other defects or high-precision cold-drawn tube was made after the cylinder, seamless steel pipe cold drawn. The use of the process of the fracture occurred, almost no plastic deformation occurs, are generally brittle fracture. Brittle fracture is caused by a variety of reasons such as: grain boundary has precipitates, regardless of its strength stronger than the matrix strength or weak, are the cause of cracks; grain boundary segregation is also the reason for the fracture; in addition, even in the far less than the yield limit of the alternating load, it will cause fatigue fracture phenomenon.

In the weld on both sides of the vertical and horizontal are not the same direction to improve the direction of inspection, the shortcomings of the echo is not the same position, showing sub-times was irregular, each of the echo signal showed a single sharp echo, and the bottom wave not seen or height drop. Probe movement in the same orientation inspection, the seamless tube echo signal showing a group of dense defects echoes, shortcomings are close to each other, bumps are not the same, the reflection of the signal of each other, fluctuated, if the resolution, then each of the individual echo signals exhibits the characteristics of the dotted defects. According to the vertical and horizontal defects in the vertical and horizontal direction of the echo and the sub-order was irregular, successive episodes of the bottom wave or bottom wave ups and downs in the 50% of the characteristics of the assessment can be judged as a dense shortcomings. More common shortcomings of dense defects such as dense pores, and then hot cracks and other shortcomings, this seamless steel pipe defects is a group of shortcomings of the mobilization, each small gap between each other close to each other can not locate each individual small quantitative. In the weld on both sides of the vertical and horizontal are not the same direction of the progress of the line check, the shortcomings of the echo is generally high and the shape of a single rule, the height of the same and no significant changes in a wide range, successive defects. And in the same direction, the bottom wave height also no significant changes, only the signal is not clear off a large interval, seamless pipe defects simply, can be measured short points indicate length ΔL. The shortcomings of the echo peak steadily from zero to the peak and hold a straight part, and then smoothly down from the peak to zero, both sides of the weld can be checked. According to the seamless steel pipe vertical and horizontal shortcomings of the height of the same as no significant change, the peak echo rise and fall characteristics can be assessed as a strip of shortcomings. The seamless pipe can be used to indicate the length of the test, but it is not easy to measure the cross-sectional scale (height and width); however, in the length direction may also be continuous, such as chain-like slag, intermittent not penetration, intermittent untreated and so on.

1. Board test: used to make large diameter submerged arc welded steel pipe into the production line, the first full-board ultrasonic inspection; 2. Milling: through the milling machine on both sides of the steel plate on both sides of the milling, so that the board to reach the demand, board parallelism and groove shape; 3. Pre-bending: the use of pre-bending machine for the edge of the pre-bend, so that the board has a curvature in line with demand; 4. Forming: In the JCO forming machine on the first half of the steel after the pre-bending through the repeated step into the stamping, pressed into the "J" shape, and then the other half of the same twists and turns, pressed into "C" shape, and ultimately constitute the opening " O "shape; 5. Pre-welding: the forming of the straight seam welded steel pipe joints and the use of gas maintenance welding (MAG) for welding; 6. Internal welding: the use of vertical multi-wire submerged arc welding (up to five wire) in the straight seam steel pipe inside the welding; 7. External welding: the use of vertical multi-wire submerged arc welding in the straight seam submerged arc welded pipe outside the welding; 8. Ultrasonic inspection Ⅰ: Longitudinal seam welded pipe on both sides of the weld and weld on both sides of the base metal 100% view; 9. X-ray inspection Ⅰ: 100% of the surface of the weld X-ray industrial TV view, the use of image processing system to ensure the sensitivity of testing; 10. Enlargement: the full length of the submerged arc welded straight pipe is expanded to improve the scale accuracy of the steel pipe and improve the distribution of the stress in the steel pipe. 11. Water pressure test: in the hydraulic press on the expansion of the steel pipe after the root inspection to ensure that the steel pipe to meet the specifications of the experimental pressure, the machine has an automatic recording and storage function; 12. Chamfering: the pipe will be qualified after the end of the pipe processing, to reach the needs of the pipe end groove scale; 13. Ultrasonic inspection Ⅱ: again by root ultrasonic inspection to see the straight seam welded steel pipe in the expansion, water pressure can occur after the shortcomings; 14. X-ray view Ⅱ: the expansion and water pressure after the test of the steel pipe X-ray industrial TV viewing and pipe-side welding film; 15. Tube-side magnetic powder inspection: to carry out this view to find the pipe terminal shortcomings; 16. Anti-corrosion and coating: qualified steel pipe according to user needs for corrosion and coating.