Iran 27 oil exhibition

Compared with the straight welded pipe, the spiral steel pipe has some advantages, such as simple production process, high production efficiency, low cost and rapid development. However, the strength of spiral welded pipe is generally higher than that of straight welded pipe. It can produce welded pipe with larger diameter with narrow blank, and can also produce welded pipe with different diameter with the same width of blank. However, compared with the same length of straight seam pipe, the weld length increases by 30-100%, and the production speed is low. Therefore, most of the welded pipes with smaller diameter are straight seam welded, while most of the welded pipes with large diameter are spiral welded.

The three-layer structure polyolefin (PE) was developed and applied in 1980s. It is an anticorrosive structure which combines FBE's excellent anti-corrosion function, cohesiveness, high resistance to cathodic disbonding and polyolefin's high impermeability, excellent mechanical function and resistance to soil stress. It has been used in many projects since its appearance, especially in its continuous application Upward trend. The bottom layer of three-layer PE is epoxy coating, the middle layer is polymer adhesive, and the surface layer is polyolefin. The adhesive can be modified polyolefin, which contains the polar group grafted to the main chain of polyolefin carbon bond. In this way, the adhesive can not only blend with unmodified polyolefin, but also react with epoxy resin by polar group. This combination is characterized by a good bond strength between the three coatings, and the functions and characteristics of each layer make the three coatings complementary, and the process is messy.

The screw steel (3606, - 34.00, - 0.93%) futures of the previous period opened at a low price of 3569 in the night of 2010, with the lowest price of 3568 yuan / ton and the highest price of 3583 yuan / ton, closing at 3575 yuan / ton, down 5 yuan / ton or 0.14% compared with the settlement price of the previous trading day.