1.Insufficient bonding strength Because there is no metallurgical bonding interface between the two metals, the bonding strength is low, generally 0.2-0.3mpa.It is easy to peel off the inner pipe due to insufficient bonding strength. 2.Poor sealing of end bevel The end bevel treatment of the mechanical composite pipe is a very key link. If the end seal is not good, it will not only lead to the peeling of the inner pipe and the outer pipe, but also affect the field butt welding. The most commonly used end treatment is seal welding and overlay welding. The welding consumables of seal welding technology are less and relatively cheap. Although it has many years of experience and is mature, its stability is relatively cheap, and the requirements for field butt welding are high, which is greatly affected by the welding level of welders. The welding consumables of overlay welding are more and the cost is more expensive , but it has good stability and high comprehensive safety. 3.Thermal coll...
According to NACE MR0175, the development and production environment of natural gas field can be divided into acidic environment and sweet environment. The acidic environment contains H 2 S and H 2 S partial pressure is greater than 0.03mpa. The sweet environment contains CO2 and Cl-, but does not contain H 2 S or H 2 S partial pressure is lower than 0.03mpa. Corrosion mechanism in acidic environment Corrosion mechanism in acidic environment H 2 S H + + HS - HS - H + + S 2- 2H + + Fe Fe 2+ + H 2 ↑ Therefore, in acidic environment, in addition to uniform corrosion and local corrosion on the surface of pipes, a series of metal ...
u Taking 316L as an example, its yield strength should be greater than or equal to 207Mpa which is specified in API specification 5LC, but still lower than that of ordinary pipeline steel. Therefore, in order to bear pressure, it is necessary to increase the wall thickness, resulting in a substantial increase in material costs. u Therefore, the bimetal clad pipe is adopted by the oil industry, on the one hand, is forced by the environment, on the other hand, it also has its own unique technical advantages. u Bimetallic clad pipe combines two advantages: high strength of base pipe and corrosion resistance of lining pipe. Compared with carbon steel and corrosion resistant alloy, bimetallic clad pipe has excellent performance and high cost performance. u Since 1991, it has been widely used after decades of development. It has also been widely recognized in the petroleum product transportation and refining industry, and the American Petroleum Institute (AP...
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