Bi-metal lined Pipes,called cladding steel pipe sometimes.The bi-metal lined pipe combines the strength, corrosion resistance and wear resistance of the base pipe and the outer pipe. It not only satisfies the special requirements but also saves costs.
In a clad line pipe, the corrosion-resistant alloy forms a complete barrier layer on the internal surface of carbon or low-alloy steel pipe (usually referred to as the “backing steel”). In general, use of clad or bi-metal-lined pipe allows the economic use of expensive CRA materials,It has been widely concerned and used in many other fields abroad.Do you know what’s the cladding steel pipe used for?
1.Casing pipe for oil and gas transportation
Choosing stainless steel such as Incoloy625 and Incoloy825 for inner tubes to ensure the corrosion resistance of the pipe. The outer pipe are usually X42, X50, X60, X70, A335-P22 and other materials to ensure the strength of the pipeline. The American Petroleum Association (API) has developed the standard for composite pipes for pipelines,with the serial number API 5LD:Cr-Mo steel,super 13Cr, G3, C028 and other oil well tubes and the nickel-base alloy cladding tubes such as 825, 028.
The steel tube for superheater should have high temperature strength under the condition of 650 and 35 MPa steam,excellent surface temperature and corrosion resistance, and inner surface resistance to water vapor oxidation.
Sandvik,a Sweden Steel Corp successfully developed carbon steel as an inner pipe and Sanicro28 steel with good corrosion resistance as outer pipe. The cladding steel pipe made by Sandvik does not need any change in the boiler structure design and can be used directly.
Cladding steel tube for waste incinerator.The outer tube can be made of Sanicro65 alloy, and the inner pipe may be carbon steel or chromium molybdenum steel with resistance to stress corrosion cracking.Europe and the United States have used 2 million meter composite steel pipe since the first installation cladding pipe incinerator superheater and water wall tubes in the 1971.
- Heat exchanger
Cladding steel pipe used for heat exchanger should also have good thermal conductivity and a certain strength and corrosion resistance.
Sandvik manufactured cladding pipe with high alloy nickel chromium alloy 800 as the inner tube and the low-alloy steel ASTM A213 Ti2 as the outer pipe.NKK company from Japan made cladding pipe with API 5L-16MnV steel as its outer pipe and NIC42 steel as inner pipe.
5.Used for wear-resistant steel
A Japan company have made cladding steel pipe with SUS316L corrosion resistant steel for outer pipe,Stellite No12 alloy for inner pipe,after 4 years is still new.They has also been well applied in the pneumatic conveying pipe of other micro powder particles, and the demand is increasing.
Inner pipe:Nickel, Titanium stainless steel or Copper alloy.
Outer pipe:Carbon steel or low alloy corrosion resistant steel.
The cost effectiveness of bi-metal-lined pipe is demonstrated by the fact that they has been used extensively abroad.The bi-metal-lined pipe has been popularized in the petroleum product transportation and refining industry of domestic oil and gas industry in recent years.However, there is still a big gap between domestic and foreign countries in terms of composite technology, efficient production and detection technology.I think there isn’t a long way to go in the popularization of bi-metal lined pipes in China.