Causes Analysis on Cracks of Nickel Pipes of a Conversion Furnace

Through the methods of macrographic examination, chemical composition analysis, metallographic examination and scanning electron microscopy analysis, the cracking causes of the nickel pipes of a conversion furnace were analyzed. The results show that the cracking cause of the nickel pipes of the conversion furnace was amounts of precipitated secondary carbides in grain boundaries and inside grains, causing the intergranular corrosion on the external wall and internal wall of the nickel pipes. The intergranular corrosion further became corrosion microcracks, and finally resulting in the corrosion perforation of the nickel pipes.