Bimetallic Metallurgical Clad Pipe

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...

The main production processes of mechanical compounding include hydraulic compounding, cold drawing compounding, underwater deflagration compounding and cold rolling compounding. Forming is based on the elastic-plastic characteristics of metal materials, that means, the elastic deformation range of outer base pipe (generally carbon steel seamless pipe) and the low yield strength of inner liner pipe (generally stainless steel pipe) are used. Under the external force, the inner tube is continuously deformed plastically, and the outer tube is always kept within the elastic deformation range. When the external force is removed, the outer tube shrinks elastically, and the inner tube cannot shrink due to the plastic deformation ， which causes the outer surface of the inner tube to be strongly embedded in the inner surface of the outer tube. Finally, the inner and outer pipes are in the state of interference fit, forming a close mechanical combination.

Bimetal pipe is a kind of pipe that lined a thin-walled corrosion-resistant alloy ， which can be selected according to corrosion environment and usual material are stainless steel 316L, nickel base alloy 825, 625, etc.. Bimetal pipe combines two advantages of the two materials and gives full play to the two advantages ， the high strength characteristics of the base pipe and the corrosion resistance of the inner pipe. The safety level of the pipeline is improved and the service life of the pipeline is prolonged. As the consumption of corrosion-resistant alloy pipe is decreased, the cost will be significantly reduced. In terms of the manufacturing method and production process of the composite pipe, Bimetal pipe can be divided into the following two types according to the combination form of outer pipe and inner pipe: Mechanical composite process and metallurgical clad process ， corresponding to the production of mechanical composite pipe and metallurgical clad pipe. mechanical comp...

  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...

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 ...