Fabrication Of Ceramic Lined Composite Steel Pipes Based SHS Technology

The ceramic-lined composite steel pipe has great potential in the application of petrochemical, mining and metallurgy industry due to its excellent performance in the resistance of wear, heat and corrosion. Hence, it's necessary to do some research on the fabrication of this promising product.In this paper, ceramic-lined composite steel pipes were respectively prepared by the SHS Gravitational-thermite Process and SHS-Centrifuging, both of which are on the basis of Self-propagating High-temperature Synthesis (SHS). Referring to the former method, the reaction thermodynamics of thermite, the mixture ratio of each ingredient and additive in whole system combined with other factors which have great impacts on the quality of the inner ceramic coating were mainly discussed. Regarding the latter technique, a SHS Centrifuge was self-designed and manufactured according to the requirement of concrete slurry pipeline produced by SANY Corporation. It turns out that Fe₂O₃-Al is a suitable and inexpensive system for the SHS reaction. In addition, a compound additive comprises SiO₂, CaF2 and CrO₃ will enhance the compactness of coatings. This coating was mainly composed of Al2O3, complex compounds and Fe, the first two materials were just like dendrite crystal while the iron was morphologically sphere and dispersedly distributed in the ceramic. Moreover, optimal interface layers, consisted of compounds contained Al, Fe, O, Ca, Si and other elements, were found in some parts of the pipe. However, the interface of ceramic and steel in the composite steel pipe, fabricated by the process of SHS-Centrifuging, is generally primitive mechanical bonding which results in a poor adhesion strength. It is considered after comprehensive analysis that thin-walled steel pipe (3mm) and fast heat conduction of the steel pipe are the main cause leads to a bad interface. Therefore, obtaining the perfect interface layer and improve the bonding between coatings of ceramic and steel are the focus of future study in the manufacture of composite steel pipes with small caliber and thin walls.